ASR_BASE
Change-Id: Icf3719cc0afe3eeb3edc7fa80a2eb5199ca9dda1
diff --git a/marvell/linux/kernel/sched/fair.c b/marvell/linux/kernel/sched/fair.c
new file mode 100644
index 0000000..d17f07f
--- /dev/null
+++ b/marvell/linux/kernel/sched/fair.c
@@ -0,0 +1,10959 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Completely Fair Scheduling (CFS) Class (SCHED_NORMAL/SCHED_BATCH)
+ *
+ * Copyright (C) 2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ *
+ * Interactivity improvements by Mike Galbraith
+ * (C) 2007 Mike Galbraith <efault@gmx.de>
+ *
+ * Various enhancements by Dmitry Adamushko.
+ * (C) 2007 Dmitry Adamushko <dmitry.adamushko@gmail.com>
+ *
+ * Group scheduling enhancements by Srivatsa Vaddagiri
+ * Copyright IBM Corporation, 2007
+ * Author: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
+ *
+ * Scaled math optimizations by Thomas Gleixner
+ * Copyright (C) 2007, Thomas Gleixner <tglx@linutronix.de>
+ *
+ * Adaptive scheduling granularity, math enhancements by Peter Zijlstra
+ * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra
+ */
+#include "sched.h"
+
+#include <trace/events/sched.h>
+#include <trace/hooks/sched.h>
+
+/*
+ * Targeted preemption latency for CPU-bound tasks:
+ *
+ * NOTE: this latency value is not the same as the concept of
+ * 'timeslice length' - timeslices in CFS are of variable length
+ * and have no persistent notion like in traditional, time-slice
+ * based scheduling concepts.
+ *
+ * (to see the precise effective timeslice length of your workload,
+ * run vmstat and monitor the context-switches (cs) field)
+ *
+ * (default: 6ms * (1 + ilog(ncpus)), units: nanoseconds)
+ */
+unsigned int sysctl_sched_latency = 6000000ULL;
+static unsigned int normalized_sysctl_sched_latency = 6000000ULL;
+
+/*
+ * The initial- and re-scaling of tunables is configurable
+ *
+ * Options are:
+ *
+ * SCHED_TUNABLESCALING_NONE - unscaled, always *1
+ * SCHED_TUNABLESCALING_LOG - scaled logarithmical, *1+ilog(ncpus)
+ * SCHED_TUNABLESCALING_LINEAR - scaled linear, *ncpus
+ *
+ * (default SCHED_TUNABLESCALING_LOG = *(1+ilog(ncpus))
+ */
+enum sched_tunable_scaling sysctl_sched_tunable_scaling = SCHED_TUNABLESCALING_LOG;
+
+/*
+ * Minimal preemption granularity for CPU-bound tasks:
+ *
+ * (default: 0.75 msec * (1 + ilog(ncpus)), units: nanoseconds)
+ */
+unsigned int sysctl_sched_min_granularity = 750000ULL;
+static unsigned int normalized_sysctl_sched_min_granularity = 750000ULL;
+
+/*
+ * This value is kept at sysctl_sched_latency/sysctl_sched_min_granularity
+ */
+static unsigned int sched_nr_latency = 8;
+
+/*
+ * After fork, child runs first. If set to 0 (default) then
+ * parent will (try to) run first.
+ */
+unsigned int sysctl_sched_child_runs_first __read_mostly;
+
+/*
+ * SCHED_OTHER wake-up granularity.
+ *
+ * This option delays the preemption effects of decoupled workloads
+ * and reduces their over-scheduling. Synchronous workloads will still
+ * have immediate wakeup/sleep latencies.
+ *
+ * (default: 1 msec * (1 + ilog(ncpus)), units: nanoseconds)
+ */
+unsigned int sysctl_sched_wakeup_granularity = 1000000UL;
+static unsigned int normalized_sysctl_sched_wakeup_granularity = 1000000UL;
+
+const_debug unsigned int sysctl_sched_migration_cost = 500000UL;
+
+#ifdef CONFIG_SMP
+/*
+ * For asym packing, by default the lower numbered CPU has higher priority.
+ */
+int __weak arch_asym_cpu_priority(int cpu)
+{
+ return -cpu;
+}
+
+/*
+ * The margin used when comparing utilization with CPU capacity.
+ *
+ * (default: ~20%)
+ */
+#define fits_capacity(cap, max) ((cap) * 1280 < (max) * 1024)
+
+#endif
+
+#ifdef CONFIG_CFS_BANDWIDTH
+/*
+ * Amount of runtime to allocate from global (tg) to local (per-cfs_rq) pool
+ * each time a cfs_rq requests quota.
+ *
+ * Note: in the case that the slice exceeds the runtime remaining (either due
+ * to consumption or the quota being specified to be smaller than the slice)
+ * we will always only issue the remaining available time.
+ *
+ * (default: 5 msec, units: microseconds)
+ */
+unsigned int sysctl_sched_cfs_bandwidth_slice = 5000UL;
+#endif
+
+static inline void update_load_add(struct load_weight *lw, unsigned long inc)
+{
+ lw->weight += inc;
+ lw->inv_weight = 0;
+}
+
+static inline void update_load_sub(struct load_weight *lw, unsigned long dec)
+{
+ lw->weight -= dec;
+ lw->inv_weight = 0;
+}
+
+static inline void update_load_set(struct load_weight *lw, unsigned long w)
+{
+ lw->weight = w;
+ lw->inv_weight = 0;
+}
+
+/*
+ * Increase the granularity value when there are more CPUs,
+ * because with more CPUs the 'effective latency' as visible
+ * to users decreases. But the relationship is not linear,
+ * so pick a second-best guess by going with the log2 of the
+ * number of CPUs.
+ *
+ * This idea comes from the SD scheduler of Con Kolivas:
+ */
+static unsigned int get_update_sysctl_factor(void)
+{
+ unsigned int cpus = min_t(unsigned int, num_online_cpus(), 8);
+ unsigned int factor;
+
+ switch (sysctl_sched_tunable_scaling) {
+ case SCHED_TUNABLESCALING_NONE:
+ factor = 1;
+ break;
+ case SCHED_TUNABLESCALING_LINEAR:
+ factor = cpus;
+ break;
+ case SCHED_TUNABLESCALING_LOG:
+ default:
+ factor = 1 + ilog2(cpus);
+ break;
+ }
+
+ return factor;
+}
+
+static void update_sysctl(void)
+{
+ unsigned int factor = get_update_sysctl_factor();
+
+#define SET_SYSCTL(name) \
+ (sysctl_##name = (factor) * normalized_sysctl_##name)
+ SET_SYSCTL(sched_min_granularity);
+ SET_SYSCTL(sched_latency);
+ SET_SYSCTL(sched_wakeup_granularity);
+#undef SET_SYSCTL
+}
+
+void sched_init_granularity(void)
+{
+ update_sysctl();
+}
+
+#define WMULT_CONST (~0U)
+#define WMULT_SHIFT 32
+
+static void __update_inv_weight(struct load_weight *lw)
+{
+ unsigned long w;
+
+ if (likely(lw->inv_weight))
+ return;
+
+ w = scale_load_down(lw->weight);
+
+ if (BITS_PER_LONG > 32 && unlikely(w >= WMULT_CONST))
+ lw->inv_weight = 1;
+ else if (unlikely(!w))
+ lw->inv_weight = WMULT_CONST;
+ else
+ lw->inv_weight = WMULT_CONST / w;
+}
+
+/*
+ * delta_exec * weight / lw.weight
+ * OR
+ * (delta_exec * (weight * lw->inv_weight)) >> WMULT_SHIFT
+ *
+ * Either weight := NICE_0_LOAD and lw \e sched_prio_to_wmult[], in which case
+ * we're guaranteed shift stays positive because inv_weight is guaranteed to
+ * fit 32 bits, and NICE_0_LOAD gives another 10 bits; therefore shift >= 22.
+ *
+ * Or, weight =< lw.weight (because lw.weight is the runqueue weight), thus
+ * weight/lw.weight <= 1, and therefore our shift will also be positive.
+ */
+static u64 __calc_delta(u64 delta_exec, unsigned long weight, struct load_weight *lw)
+{
+ u64 fact = scale_load_down(weight);
+ int shift = WMULT_SHIFT;
+
+ __update_inv_weight(lw);
+
+ if (unlikely(fact >> 32)) {
+ while (fact >> 32) {
+ fact >>= 1;
+ shift--;
+ }
+ }
+
+ /* hint to use a 32x32->64 mul */
+ fact = (u64)(u32)fact * lw->inv_weight;
+
+ while (fact >> 32) {
+ fact >>= 1;
+ shift--;
+ }
+
+ return mul_u64_u32_shr(delta_exec, fact, shift);
+}
+
+
+const struct sched_class fair_sched_class;
+
+/**************************************************************
+ * CFS operations on generic schedulable entities:
+ */
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+static inline struct task_struct *task_of(struct sched_entity *se)
+{
+ SCHED_WARN_ON(!entity_is_task(se));
+ return container_of(se, struct task_struct, se);
+}
+
+/* Walk up scheduling entities hierarchy */
+#define for_each_sched_entity(se) \
+ for (; se; se = se->parent)
+
+static inline struct cfs_rq *task_cfs_rq(struct task_struct *p)
+{
+ return p->se.cfs_rq;
+}
+
+/* runqueue on which this entity is (to be) queued */
+static inline struct cfs_rq *cfs_rq_of(struct sched_entity *se)
+{
+ return se->cfs_rq;
+}
+
+/* runqueue "owned" by this group */
+static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp)
+{
+ return grp->my_q;
+}
+
+static inline void cfs_rq_tg_path(struct cfs_rq *cfs_rq, char *path, int len)
+{
+ if (!path)
+ return;
+
+ if (cfs_rq && task_group_is_autogroup(cfs_rq->tg))
+ autogroup_path(cfs_rq->tg, path, len);
+ else if (cfs_rq && cfs_rq->tg->css.cgroup)
+ cgroup_path(cfs_rq->tg->css.cgroup, path, len);
+ else
+ strlcpy(path, "(null)", len);
+}
+
+static inline bool list_add_leaf_cfs_rq(struct cfs_rq *cfs_rq)
+{
+ struct rq *rq = rq_of(cfs_rq);
+ int cpu = cpu_of(rq);
+
+ if (cfs_rq->on_list)
+ return rq->tmp_alone_branch == &rq->leaf_cfs_rq_list;
+
+ cfs_rq->on_list = 1;
+
+ /*
+ * Ensure we either appear before our parent (if already
+ * enqueued) or force our parent to appear after us when it is
+ * enqueued. The fact that we always enqueue bottom-up
+ * reduces this to two cases and a special case for the root
+ * cfs_rq. Furthermore, it also means that we will always reset
+ * tmp_alone_branch either when the branch is connected
+ * to a tree or when we reach the top of the tree
+ */
+ if (cfs_rq->tg->parent &&
+ cfs_rq->tg->parent->cfs_rq[cpu]->on_list) {
+ /*
+ * If parent is already on the list, we add the child
+ * just before. Thanks to circular linked property of
+ * the list, this means to put the child at the tail
+ * of the list that starts by parent.
+ */
+ list_add_tail_rcu(&cfs_rq->leaf_cfs_rq_list,
+ &(cfs_rq->tg->parent->cfs_rq[cpu]->leaf_cfs_rq_list));
+ /*
+ * The branch is now connected to its tree so we can
+ * reset tmp_alone_branch to the beginning of the
+ * list.
+ */
+ rq->tmp_alone_branch = &rq->leaf_cfs_rq_list;
+ return true;
+ }
+
+ if (!cfs_rq->tg->parent) {
+ /*
+ * cfs rq without parent should be put
+ * at the tail of the list.
+ */
+ list_add_tail_rcu(&cfs_rq->leaf_cfs_rq_list,
+ &rq->leaf_cfs_rq_list);
+ /*
+ * We have reach the top of a tree so we can reset
+ * tmp_alone_branch to the beginning of the list.
+ */
+ rq->tmp_alone_branch = &rq->leaf_cfs_rq_list;
+ return true;
+ }
+
+ /*
+ * The parent has not already been added so we want to
+ * make sure that it will be put after us.
+ * tmp_alone_branch points to the begin of the branch
+ * where we will add parent.
+ */
+ list_add_rcu(&cfs_rq->leaf_cfs_rq_list, rq->tmp_alone_branch);
+ /*
+ * update tmp_alone_branch to points to the new begin
+ * of the branch
+ */
+ rq->tmp_alone_branch = &cfs_rq->leaf_cfs_rq_list;
+ return false;
+}
+
+static inline void list_del_leaf_cfs_rq(struct cfs_rq *cfs_rq)
+{
+ if (cfs_rq->on_list) {
+ struct rq *rq = rq_of(cfs_rq);
+
+ /*
+ * With cfs_rq being unthrottled/throttled during an enqueue,
+ * it can happen the tmp_alone_branch points the a leaf that
+ * we finally want to del. In this case, tmp_alone_branch moves
+ * to the prev element but it will point to rq->leaf_cfs_rq_list
+ * at the end of the enqueue.
+ */
+ if (rq->tmp_alone_branch == &cfs_rq->leaf_cfs_rq_list)
+ rq->tmp_alone_branch = cfs_rq->leaf_cfs_rq_list.prev;
+
+ list_del_rcu(&cfs_rq->leaf_cfs_rq_list);
+ cfs_rq->on_list = 0;
+ }
+}
+
+static inline void assert_list_leaf_cfs_rq(struct rq *rq)
+{
+ SCHED_WARN_ON(rq->tmp_alone_branch != &rq->leaf_cfs_rq_list);
+}
+
+/* Iterate thr' all leaf cfs_rq's on a runqueue */
+#define for_each_leaf_cfs_rq_safe(rq, cfs_rq, pos) \
+ list_for_each_entry_safe(cfs_rq, pos, &rq->leaf_cfs_rq_list, \
+ leaf_cfs_rq_list)
+
+/* Do the two (enqueued) entities belong to the same group ? */
+static inline struct cfs_rq *
+is_same_group(struct sched_entity *se, struct sched_entity *pse)
+{
+ if (se->cfs_rq == pse->cfs_rq)
+ return se->cfs_rq;
+
+ return NULL;
+}
+
+static inline struct sched_entity *parent_entity(struct sched_entity *se)
+{
+ return se->parent;
+}
+
+static void
+find_matching_se(struct sched_entity **se, struct sched_entity **pse)
+{
+ int se_depth, pse_depth;
+
+ /*
+ * preemption test can be made between sibling entities who are in the
+ * same cfs_rq i.e who have a common parent. Walk up the hierarchy of
+ * both tasks until we find their ancestors who are siblings of common
+ * parent.
+ */
+
+ /* First walk up until both entities are at same depth */
+ se_depth = (*se)->depth;
+ pse_depth = (*pse)->depth;
+
+ while (se_depth > pse_depth) {
+ se_depth--;
+ *se = parent_entity(*se);
+ }
+
+ while (pse_depth > se_depth) {
+ pse_depth--;
+ *pse = parent_entity(*pse);
+ }
+
+ while (!is_same_group(*se, *pse)) {
+ *se = parent_entity(*se);
+ *pse = parent_entity(*pse);
+ }
+}
+
+#else /* !CONFIG_FAIR_GROUP_SCHED */
+
+static inline struct task_struct *task_of(struct sched_entity *se)
+{
+ return container_of(se, struct task_struct, se);
+}
+
+#define for_each_sched_entity(se) \
+ for (; se; se = NULL)
+
+static inline struct cfs_rq *task_cfs_rq(struct task_struct *p)
+{
+ return &task_rq(p)->cfs;
+}
+
+static inline struct cfs_rq *cfs_rq_of(struct sched_entity *se)
+{
+ struct task_struct *p = task_of(se);
+ struct rq *rq = task_rq(p);
+
+ return &rq->cfs;
+}
+
+/* runqueue "owned" by this group */
+static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp)
+{
+ return NULL;
+}
+
+static inline void cfs_rq_tg_path(struct cfs_rq *cfs_rq, char *path, int len)
+{
+ if (path)
+ strlcpy(path, "(null)", len);
+}
+
+static inline bool list_add_leaf_cfs_rq(struct cfs_rq *cfs_rq)
+{
+ return true;
+}
+
+static inline void list_del_leaf_cfs_rq(struct cfs_rq *cfs_rq)
+{
+}
+
+static inline void assert_list_leaf_cfs_rq(struct rq *rq)
+{
+}
+
+#define for_each_leaf_cfs_rq_safe(rq, cfs_rq, pos) \
+ for (cfs_rq = &rq->cfs, pos = NULL; cfs_rq; cfs_rq = pos)
+
+static inline struct sched_entity *parent_entity(struct sched_entity *se)
+{
+ return NULL;
+}
+
+static inline void
+find_matching_se(struct sched_entity **se, struct sched_entity **pse)
+{
+}
+
+#endif /* CONFIG_FAIR_GROUP_SCHED */
+
+static __always_inline
+void account_cfs_rq_runtime(struct cfs_rq *cfs_rq, u64 delta_exec);
+
+/**************************************************************
+ * Scheduling class tree data structure manipulation methods:
+ */
+
+static inline u64 max_vruntime(u64 max_vruntime, u64 vruntime)
+{
+ s64 delta = (s64)(vruntime - max_vruntime);
+ if (delta > 0)
+ max_vruntime = vruntime;
+
+ return max_vruntime;
+}
+
+static inline u64 min_vruntime(u64 min_vruntime, u64 vruntime)
+{
+ s64 delta = (s64)(vruntime - min_vruntime);
+ if (delta < 0)
+ min_vruntime = vruntime;
+
+ return min_vruntime;
+}
+
+static inline int entity_before(struct sched_entity *a,
+ struct sched_entity *b)
+{
+ return (s64)(a->vruntime - b->vruntime) < 0;
+}
+
+static void update_min_vruntime(struct cfs_rq *cfs_rq)
+{
+ struct sched_entity *curr = cfs_rq->curr;
+ struct rb_node *leftmost = rb_first_cached(&cfs_rq->tasks_timeline);
+
+ u64 vruntime = cfs_rq->min_vruntime;
+
+ if (curr) {
+ if (curr->on_rq)
+ vruntime = curr->vruntime;
+ else
+ curr = NULL;
+ }
+
+ if (leftmost) { /* non-empty tree */
+ struct sched_entity *se;
+ se = rb_entry(leftmost, struct sched_entity, run_node);
+
+ if (!curr)
+ vruntime = se->vruntime;
+ else
+ vruntime = min_vruntime(vruntime, se->vruntime);
+ }
+
+ /* ensure we never gain time by being placed backwards. */
+ cfs_rq->min_vruntime = max_vruntime(cfs_rq->min_vruntime, vruntime);
+#ifndef CONFIG_64BIT
+ smp_wmb();
+ cfs_rq->min_vruntime_copy = cfs_rq->min_vruntime;
+#endif
+}
+
+/*
+ * Enqueue an entity into the rb-tree:
+ */
+static void __enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+ struct rb_node **link = &cfs_rq->tasks_timeline.rb_root.rb_node;
+ struct rb_node *parent = NULL;
+ struct sched_entity *entry;
+ bool leftmost = true;
+
+ /*
+ * Find the right place in the rbtree:
+ */
+ while (*link) {
+ parent = *link;
+ entry = rb_entry(parent, struct sched_entity, run_node);
+ /*
+ * We dont care about collisions. Nodes with
+ * the same key stay together.
+ */
+ if (entity_before(se, entry)) {
+ link = &parent->rb_left;
+ } else {
+ link = &parent->rb_right;
+ leftmost = false;
+ }
+ }
+
+ rb_link_node(&se->run_node, parent, link);
+ rb_insert_color_cached(&se->run_node,
+ &cfs_rq->tasks_timeline, leftmost);
+}
+
+static void __dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+ rb_erase_cached(&se->run_node, &cfs_rq->tasks_timeline);
+}
+
+struct sched_entity *__pick_first_entity(struct cfs_rq *cfs_rq)
+{
+ struct rb_node *left = rb_first_cached(&cfs_rq->tasks_timeline);
+
+ if (!left)
+ return NULL;
+
+ return rb_entry(left, struct sched_entity, run_node);
+}
+
+static struct sched_entity *__pick_next_entity(struct sched_entity *se)
+{
+ struct rb_node *next = rb_next(&se->run_node);
+
+ if (!next)
+ return NULL;
+
+ return rb_entry(next, struct sched_entity, run_node);
+}
+
+#ifdef CONFIG_SCHED_DEBUG
+struct sched_entity *__pick_last_entity(struct cfs_rq *cfs_rq)
+{
+ struct rb_node *last = rb_last(&cfs_rq->tasks_timeline.rb_root);
+
+ if (!last)
+ return NULL;
+
+ return rb_entry(last, struct sched_entity, run_node);
+}
+
+/**************************************************************
+ * Scheduling class statistics methods:
+ */
+
+int sched_proc_update_handler(struct ctl_table *table, int write,
+ void __user *buffer, size_t *lenp,
+ loff_t *ppos)
+{
+ int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
+ unsigned int factor = get_update_sysctl_factor();
+
+ if (ret || !write)
+ return ret;
+
+ sched_nr_latency = DIV_ROUND_UP(sysctl_sched_latency,
+ sysctl_sched_min_granularity);
+
+#define WRT_SYSCTL(name) \
+ (normalized_sysctl_##name = sysctl_##name / (factor))
+ WRT_SYSCTL(sched_min_granularity);
+ WRT_SYSCTL(sched_latency);
+ WRT_SYSCTL(sched_wakeup_granularity);
+#undef WRT_SYSCTL
+
+ return 0;
+}
+#endif
+
+/*
+ * delta /= w
+ */
+static inline u64 calc_delta_fair(u64 delta, struct sched_entity *se)
+{
+ if (unlikely(se->load.weight != NICE_0_LOAD))
+ delta = __calc_delta(delta, NICE_0_LOAD, &se->load);
+
+ return delta;
+}
+
+/*
+ * The idea is to set a period in which each task runs once.
+ *
+ * When there are too many tasks (sched_nr_latency) we have to stretch
+ * this period because otherwise the slices get too small.
+ *
+ * p = (nr <= nl) ? l : l*nr/nl
+ */
+static u64 __sched_period(unsigned long nr_running)
+{
+ if (unlikely(nr_running > sched_nr_latency))
+ return nr_running * sysctl_sched_min_granularity;
+ else
+ return sysctl_sched_latency;
+}
+
+/*
+ * We calculate the wall-time slice from the period by taking a part
+ * proportional to the weight.
+ *
+ * s = p*P[w/rw]
+ */
+static u64 sched_slice(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+ u64 slice = __sched_period(cfs_rq->nr_running + !se->on_rq);
+
+ for_each_sched_entity(se) {
+ struct load_weight *load;
+ struct load_weight lw;
+
+ cfs_rq = cfs_rq_of(se);
+ load = &cfs_rq->load;
+
+ if (unlikely(!se->on_rq)) {
+ lw = cfs_rq->load;
+
+ update_load_add(&lw, se->load.weight);
+ load = &lw;
+ }
+ slice = __calc_delta(slice, se->load.weight, load);
+ }
+ return slice;
+}
+
+/*
+ * We calculate the vruntime slice of a to-be-inserted task.
+ *
+ * vs = s/w
+ */
+static u64 sched_vslice(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+ return calc_delta_fair(sched_slice(cfs_rq, se), se);
+}
+
+#include "pelt.h"
+#ifdef CONFIG_SMP
+
+static int select_idle_sibling(struct task_struct *p, int prev_cpu, int cpu);
+static unsigned long task_h_load(struct task_struct *p);
+static unsigned long capacity_of(int cpu);
+
+/* Give new sched_entity start runnable values to heavy its load in infant time */
+void init_entity_runnable_average(struct sched_entity *se)
+{
+ struct sched_avg *sa = &se->avg;
+
+ memset(sa, 0, sizeof(*sa));
+
+ /*
+ * Tasks are initialized with full load to be seen as heavy tasks until
+ * they get a chance to stabilize to their real load level.
+ * Group entities are initialized with zero load to reflect the fact that
+ * nothing has been attached to the task group yet.
+ */
+ if (entity_is_task(se))
+ sa->runnable_load_avg = sa->load_avg = scale_load_down(se->load.weight);
+
+ se->runnable_weight = se->load.weight;
+
+ /* when this task enqueue'ed, it will contribute to its cfs_rq's load_avg */
+}
+
+static void attach_entity_cfs_rq(struct sched_entity *se);
+
+/*
+ * With new tasks being created, their initial util_avgs are extrapolated
+ * based on the cfs_rq's current util_avg:
+ *
+ * util_avg = cfs_rq->util_avg / (cfs_rq->load_avg + 1) * se.load.weight
+ *
+ * However, in many cases, the above util_avg does not give a desired
+ * value. Moreover, the sum of the util_avgs may be divergent, such
+ * as when the series is a harmonic series.
+ *
+ * To solve this problem, we also cap the util_avg of successive tasks to
+ * only 1/2 of the left utilization budget:
+ *
+ * util_avg_cap = (cpu_scale - cfs_rq->avg.util_avg) / 2^n
+ *
+ * where n denotes the nth task and cpu_scale the CPU capacity.
+ *
+ * For example, for a CPU with 1024 of capacity, a simplest series from
+ * the beginning would be like:
+ *
+ * task util_avg: 512, 256, 128, 64, 32, 16, 8, ...
+ * cfs_rq util_avg: 512, 768, 896, 960, 992, 1008, 1016, ...
+ *
+ * Finally, that extrapolated util_avg is clamped to the cap (util_avg_cap)
+ * if util_avg > util_avg_cap.
+ */
+void post_init_entity_util_avg(struct task_struct *p)
+{
+ struct sched_entity *se = &p->se;
+ struct cfs_rq *cfs_rq = cfs_rq_of(se);
+ struct sched_avg *sa = &se->avg;
+ long cpu_scale = arch_scale_cpu_capacity(cpu_of(rq_of(cfs_rq)));
+ long cap = (long)(cpu_scale - cfs_rq->avg.util_avg) / 2;
+
+ if (cap > 0) {
+ if (cfs_rq->avg.util_avg != 0) {
+ sa->util_avg = cfs_rq->avg.util_avg * se->load.weight;
+ sa->util_avg /= (cfs_rq->avg.load_avg + 1);
+
+ if (sa->util_avg > cap)
+ sa->util_avg = cap;
+ } else {
+ sa->util_avg = cap;
+ }
+ }
+
+ if (p->sched_class != &fair_sched_class) {
+ /*
+ * For !fair tasks do:
+ *
+ update_cfs_rq_load_avg(now, cfs_rq);
+ attach_entity_load_avg(cfs_rq, se, 0);
+ switched_from_fair(rq, p);
+ *
+ * such that the next switched_to_fair() has the
+ * expected state.
+ */
+ se->avg.last_update_time = cfs_rq_clock_pelt(cfs_rq);
+ return;
+ }
+
+ attach_entity_cfs_rq(se);
+}
+
+#else /* !CONFIG_SMP */
+void init_entity_runnable_average(struct sched_entity *se)
+{
+}
+void post_init_entity_util_avg(struct task_struct *p)
+{
+}
+static void update_tg_load_avg(struct cfs_rq *cfs_rq, int force)
+{
+}
+#endif /* CONFIG_SMP */
+
+/*
+ * Update the current task's runtime statistics.
+ */
+static void update_curr(struct cfs_rq *cfs_rq)
+{
+ struct sched_entity *curr = cfs_rq->curr;
+ u64 now = rq_clock_task(rq_of(cfs_rq));
+ u64 delta_exec;
+
+ if (unlikely(!curr))
+ return;
+
+ delta_exec = now - curr->exec_start;
+ if (unlikely((s64)delta_exec <= 0))
+ return;
+
+ curr->exec_start = now;
+
+ schedstat_set(curr->statistics.exec_max,
+ max(delta_exec, curr->statistics.exec_max));
+
+ curr->sum_exec_runtime += delta_exec;
+ schedstat_add(cfs_rq->exec_clock, delta_exec);
+
+ curr->vruntime += calc_delta_fair(delta_exec, curr);
+ update_min_vruntime(cfs_rq);
+
+ if (entity_is_task(curr)) {
+ struct task_struct *curtask = task_of(curr);
+
+ trace_sched_stat_runtime(curtask, delta_exec, curr->vruntime);
+ cgroup_account_cputime(curtask, delta_exec);
+ account_group_exec_runtime(curtask, delta_exec);
+ }
+
+ account_cfs_rq_runtime(cfs_rq, delta_exec);
+}
+
+static void update_curr_fair(struct rq *rq)
+{
+ update_curr(cfs_rq_of(&rq->curr->se));
+}
+
+static inline void
+update_stats_wait_start(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+ u64 wait_start, prev_wait_start;
+
+ if (!schedstat_enabled())
+ return;
+
+ wait_start = rq_clock(rq_of(cfs_rq));
+ prev_wait_start = schedstat_val(se->statistics.wait_start);
+
+ if (entity_is_task(se) && task_on_rq_migrating(task_of(se)) &&
+ likely(wait_start > prev_wait_start))
+ wait_start -= prev_wait_start;
+
+ __schedstat_set(se->statistics.wait_start, wait_start);
+}
+
+static inline void
+update_stats_wait_end(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+ struct task_struct *p;
+ u64 delta;
+
+ if (!schedstat_enabled())
+ return;
+
+ delta = rq_clock(rq_of(cfs_rq)) - schedstat_val(se->statistics.wait_start);
+
+ if (entity_is_task(se)) {
+ p = task_of(se);
+ if (task_on_rq_migrating(p)) {
+ /*
+ * Preserve migrating task's wait time so wait_start
+ * time stamp can be adjusted to accumulate wait time
+ * prior to migration.
+ */
+ __schedstat_set(se->statistics.wait_start, delta);
+ return;
+ }
+ trace_sched_stat_wait(p, delta);
+ }
+
+ __schedstat_set(se->statistics.wait_max,
+ max(schedstat_val(se->statistics.wait_max), delta));
+ __schedstat_inc(se->statistics.wait_count);
+ __schedstat_add(se->statistics.wait_sum, delta);
+ __schedstat_set(se->statistics.wait_start, 0);
+}
+
+static inline void
+update_stats_enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+ struct task_struct *tsk = NULL;
+ u64 sleep_start, block_start;
+
+ if (!schedstat_enabled())
+ return;
+
+ sleep_start = schedstat_val(se->statistics.sleep_start);
+ block_start = schedstat_val(se->statistics.block_start);
+
+ if (entity_is_task(se))
+ tsk = task_of(se);
+
+ if (sleep_start) {
+ u64 delta = rq_clock(rq_of(cfs_rq)) - sleep_start;
+
+ if ((s64)delta < 0)
+ delta = 0;
+
+ if (unlikely(delta > schedstat_val(se->statistics.sleep_max)))
+ __schedstat_set(se->statistics.sleep_max, delta);
+
+ __schedstat_set(se->statistics.sleep_start, 0);
+ __schedstat_add(se->statistics.sum_sleep_runtime, delta);
+
+ if (tsk) {
+ account_scheduler_latency(tsk, delta >> 10, 1);
+ trace_sched_stat_sleep(tsk, delta);
+ }
+ }
+ if (block_start) {
+ u64 delta = rq_clock(rq_of(cfs_rq)) - block_start;
+
+ if ((s64)delta < 0)
+ delta = 0;
+
+ if (unlikely(delta > schedstat_val(se->statistics.block_max)))
+ __schedstat_set(se->statistics.block_max, delta);
+
+ __schedstat_set(se->statistics.block_start, 0);
+ __schedstat_add(se->statistics.sum_sleep_runtime, delta);
+
+ if (tsk) {
+ if (tsk->in_iowait) {
+ __schedstat_add(se->statistics.iowait_sum, delta);
+ __schedstat_inc(se->statistics.iowait_count);
+ trace_sched_stat_iowait(tsk, delta);
+ }
+
+ trace_sched_stat_blocked(tsk, delta);
+ trace_sched_blocked_reason(tsk);
+
+ /*
+ * Blocking time is in units of nanosecs, so shift by
+ * 20 to get a milliseconds-range estimation of the
+ * amount of time that the task spent sleeping:
+ */
+ if (unlikely(prof_on == SLEEP_PROFILING)) {
+ profile_hits(SLEEP_PROFILING,
+ (void *)get_wchan(tsk),
+ delta >> 20);
+ }
+ account_scheduler_latency(tsk, delta >> 10, 0);
+ }
+ }
+}
+
+/*
+ * Task is being enqueued - update stats:
+ */
+static inline void
+update_stats_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
+{
+ if (!schedstat_enabled())
+ return;
+
+ /*
+ * Are we enqueueing a waiting task? (for current tasks
+ * a dequeue/enqueue event is a NOP)
+ */
+ if (se != cfs_rq->curr)
+ update_stats_wait_start(cfs_rq, se);
+
+ if (flags & ENQUEUE_WAKEUP)
+ update_stats_enqueue_sleeper(cfs_rq, se);
+}
+
+static inline void
+update_stats_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
+{
+
+ if (!schedstat_enabled())
+ return;
+
+ /*
+ * Mark the end of the wait period if dequeueing a
+ * waiting task:
+ */
+ if (se != cfs_rq->curr)
+ update_stats_wait_end(cfs_rq, se);
+
+ if ((flags & DEQUEUE_SLEEP) && entity_is_task(se)) {
+ struct task_struct *tsk = task_of(se);
+
+ if (tsk->state & TASK_INTERRUPTIBLE)
+ __schedstat_set(se->statistics.sleep_start,
+ rq_clock(rq_of(cfs_rq)));
+ if (tsk->state & TASK_UNINTERRUPTIBLE)
+ __schedstat_set(se->statistics.block_start,
+ rq_clock(rq_of(cfs_rq)));
+ }
+}
+
+/*
+ * We are picking a new current task - update its stats:
+ */
+static inline void
+update_stats_curr_start(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+ /*
+ * We are starting a new run period:
+ */
+ se->exec_start = rq_clock_task(rq_of(cfs_rq));
+}
+
+/**************************************************
+ * Scheduling class queueing methods:
+ */
+
+#ifdef CONFIG_NUMA_BALANCING
+/*
+ * Approximate time to scan a full NUMA task in ms. The task scan period is
+ * calculated based on the tasks virtual memory size and
+ * numa_balancing_scan_size.
+ */
+unsigned int sysctl_numa_balancing_scan_period_min = 1000;
+unsigned int sysctl_numa_balancing_scan_period_max = 60000;
+
+/* Portion of address space to scan in MB */
+unsigned int sysctl_numa_balancing_scan_size = 256;
+
+/* Scan @scan_size MB every @scan_period after an initial @scan_delay in ms */
+unsigned int sysctl_numa_balancing_scan_delay = 1000;
+
+struct numa_group {
+ refcount_t refcount;
+
+ spinlock_t lock; /* nr_tasks, tasks */
+ int nr_tasks;
+ pid_t gid;
+ int active_nodes;
+
+ struct rcu_head rcu;
+ unsigned long total_faults;
+ unsigned long max_faults_cpu;
+ /*
+ * Faults_cpu is used to decide whether memory should move
+ * towards the CPU. As a consequence, these stats are weighted
+ * more by CPU use than by memory faults.
+ */
+ unsigned long *faults_cpu;
+ unsigned long faults[0];
+};
+
+/*
+ * For functions that can be called in multiple contexts that permit reading
+ * ->numa_group (see struct task_struct for locking rules).
+ */
+static struct numa_group *deref_task_numa_group(struct task_struct *p)
+{
+ return rcu_dereference_check(p->numa_group, p == current ||
+ (lockdep_is_held(&task_rq(p)->lock) && !READ_ONCE(p->on_cpu)));
+}
+
+static struct numa_group *deref_curr_numa_group(struct task_struct *p)
+{
+ return rcu_dereference_protected(p->numa_group, p == current);
+}
+
+static inline unsigned long group_faults_priv(struct numa_group *ng);
+static inline unsigned long group_faults_shared(struct numa_group *ng);
+
+static unsigned int task_nr_scan_windows(struct task_struct *p)
+{
+ unsigned long rss = 0;
+ unsigned long nr_scan_pages;
+
+ /*
+ * Calculations based on RSS as non-present and empty pages are skipped
+ * by the PTE scanner and NUMA hinting faults should be trapped based
+ * on resident pages
+ */
+ nr_scan_pages = sysctl_numa_balancing_scan_size << (20 - PAGE_SHIFT);
+ rss = get_mm_rss(p->mm);
+ if (!rss)
+ rss = nr_scan_pages;
+
+ rss = round_up(rss, nr_scan_pages);
+ return rss / nr_scan_pages;
+}
+
+/* For sanitys sake, never scan more PTEs than MAX_SCAN_WINDOW MB/sec. */
+#define MAX_SCAN_WINDOW 2560
+
+static unsigned int task_scan_min(struct task_struct *p)
+{
+ unsigned int scan_size = READ_ONCE(sysctl_numa_balancing_scan_size);
+ unsigned int scan, floor;
+ unsigned int windows = 1;
+
+ if (scan_size < MAX_SCAN_WINDOW)
+ windows = MAX_SCAN_WINDOW / scan_size;
+ floor = 1000 / windows;
+
+ scan = sysctl_numa_balancing_scan_period_min / task_nr_scan_windows(p);
+ return max_t(unsigned int, floor, scan);
+}
+
+static unsigned int task_scan_start(struct task_struct *p)
+{
+ unsigned long smin = task_scan_min(p);
+ unsigned long period = smin;
+ struct numa_group *ng;
+
+ /* Scale the maximum scan period with the amount of shared memory. */
+ rcu_read_lock();
+ ng = rcu_dereference(p->numa_group);
+ if (ng) {
+ unsigned long shared = group_faults_shared(ng);
+ unsigned long private = group_faults_priv(ng);
+
+ period *= refcount_read(&ng->refcount);
+ period *= shared + 1;
+ period /= private + shared + 1;
+ }
+ rcu_read_unlock();
+
+ return max(smin, period);
+}
+
+static unsigned int task_scan_max(struct task_struct *p)
+{
+ unsigned long smin = task_scan_min(p);
+ unsigned long smax;
+ struct numa_group *ng;
+
+ /* Watch for min being lower than max due to floor calculations */
+ smax = sysctl_numa_balancing_scan_period_max / task_nr_scan_windows(p);
+
+ /* Scale the maximum scan period with the amount of shared memory. */
+ ng = deref_curr_numa_group(p);
+ if (ng) {
+ unsigned long shared = group_faults_shared(ng);
+ unsigned long private = group_faults_priv(ng);
+ unsigned long period = smax;
+
+ period *= refcount_read(&ng->refcount);
+ period *= shared + 1;
+ period /= private + shared + 1;
+
+ smax = max(smax, period);
+ }
+
+ return max(smin, smax);
+}
+
+static void account_numa_enqueue(struct rq *rq, struct task_struct *p)
+{
+ rq->nr_numa_running += (p->numa_preferred_nid != NUMA_NO_NODE);
+ rq->nr_preferred_running += (p->numa_preferred_nid == task_node(p));
+}
+
+static void account_numa_dequeue(struct rq *rq, struct task_struct *p)
+{
+ rq->nr_numa_running -= (p->numa_preferred_nid != NUMA_NO_NODE);
+ rq->nr_preferred_running -= (p->numa_preferred_nid == task_node(p));
+}
+
+/* Shared or private faults. */
+#define NR_NUMA_HINT_FAULT_TYPES 2
+
+/* Memory and CPU locality */
+#define NR_NUMA_HINT_FAULT_STATS (NR_NUMA_HINT_FAULT_TYPES * 2)
+
+/* Averaged statistics, and temporary buffers. */
+#define NR_NUMA_HINT_FAULT_BUCKETS (NR_NUMA_HINT_FAULT_STATS * 2)
+
+pid_t task_numa_group_id(struct task_struct *p)
+{
+ struct numa_group *ng;
+ pid_t gid = 0;
+
+ rcu_read_lock();
+ ng = rcu_dereference(p->numa_group);
+ if (ng)
+ gid = ng->gid;
+ rcu_read_unlock();
+
+ return gid;
+}
+
+/*
+ * The averaged statistics, shared & private, memory & CPU,
+ * occupy the first half of the array. The second half of the
+ * array is for current counters, which are averaged into the
+ * first set by task_numa_placement.
+ */
+static inline int task_faults_idx(enum numa_faults_stats s, int nid, int priv)
+{
+ return NR_NUMA_HINT_FAULT_TYPES * (s * nr_node_ids + nid) + priv;
+}
+
+static inline unsigned long task_faults(struct task_struct *p, int nid)
+{
+ if (!p->numa_faults)
+ return 0;
+
+ return p->numa_faults[task_faults_idx(NUMA_MEM, nid, 0)] +
+ p->numa_faults[task_faults_idx(NUMA_MEM, nid, 1)];
+}
+
+static inline unsigned long group_faults(struct task_struct *p, int nid)
+{
+ struct numa_group *ng = deref_task_numa_group(p);
+
+ if (!ng)
+ return 0;
+
+ return ng->faults[task_faults_idx(NUMA_MEM, nid, 0)] +
+ ng->faults[task_faults_idx(NUMA_MEM, nid, 1)];
+}
+
+static inline unsigned long group_faults_cpu(struct numa_group *group, int nid)
+{
+ return group->faults_cpu[task_faults_idx(NUMA_MEM, nid, 0)] +
+ group->faults_cpu[task_faults_idx(NUMA_MEM, nid, 1)];
+}
+
+static inline unsigned long group_faults_priv(struct numa_group *ng)
+{
+ unsigned long faults = 0;
+ int node;
+
+ for_each_online_node(node) {
+ faults += ng->faults[task_faults_idx(NUMA_MEM, node, 1)];
+ }
+
+ return faults;
+}
+
+static inline unsigned long group_faults_shared(struct numa_group *ng)
+{
+ unsigned long faults = 0;
+ int node;
+
+ for_each_online_node(node) {
+ faults += ng->faults[task_faults_idx(NUMA_MEM, node, 0)];
+ }
+
+ return faults;
+}
+
+/*
+ * A node triggering more than 1/3 as many NUMA faults as the maximum is
+ * considered part of a numa group's pseudo-interleaving set. Migrations
+ * between these nodes are slowed down, to allow things to settle down.
+ */
+#define ACTIVE_NODE_FRACTION 3
+
+static bool numa_is_active_node(int nid, struct numa_group *ng)
+{
+ return group_faults_cpu(ng, nid) * ACTIVE_NODE_FRACTION > ng->max_faults_cpu;
+}
+
+/* Handle placement on systems where not all nodes are directly connected. */
+static unsigned long score_nearby_nodes(struct task_struct *p, int nid,
+ int maxdist, bool task)
+{
+ unsigned long score = 0;
+ int node;
+
+ /*
+ * All nodes are directly connected, and the same distance
+ * from each other. No need for fancy placement algorithms.
+ */
+ if (sched_numa_topology_type == NUMA_DIRECT)
+ return 0;
+
+ /*
+ * This code is called for each node, introducing N^2 complexity,
+ * which should be ok given the number of nodes rarely exceeds 8.
+ */
+ for_each_online_node(node) {
+ unsigned long faults;
+ int dist = node_distance(nid, node);
+
+ /*
+ * The furthest away nodes in the system are not interesting
+ * for placement; nid was already counted.
+ */
+ if (dist == sched_max_numa_distance || node == nid)
+ continue;
+
+ /*
+ * On systems with a backplane NUMA topology, compare groups
+ * of nodes, and move tasks towards the group with the most
+ * memory accesses. When comparing two nodes at distance
+ * "hoplimit", only nodes closer by than "hoplimit" are part
+ * of each group. Skip other nodes.
+ */
+ if (sched_numa_topology_type == NUMA_BACKPLANE &&
+ dist >= maxdist)
+ continue;
+
+ /* Add up the faults from nearby nodes. */
+ if (task)
+ faults = task_faults(p, node);
+ else
+ faults = group_faults(p, node);
+
+ /*
+ * On systems with a glueless mesh NUMA topology, there are
+ * no fixed "groups of nodes". Instead, nodes that are not
+ * directly connected bounce traffic through intermediate
+ * nodes; a numa_group can occupy any set of nodes.
+ * The further away a node is, the less the faults count.
+ * This seems to result in good task placement.
+ */
+ if (sched_numa_topology_type == NUMA_GLUELESS_MESH) {
+ faults *= (sched_max_numa_distance - dist);
+ faults /= (sched_max_numa_distance - LOCAL_DISTANCE);
+ }
+
+ score += faults;
+ }
+
+ return score;
+}
+
+/*
+ * These return the fraction of accesses done by a particular task, or
+ * task group, on a particular numa node. The group weight is given a
+ * larger multiplier, in order to group tasks together that are almost
+ * evenly spread out between numa nodes.
+ */
+static inline unsigned long task_weight(struct task_struct *p, int nid,
+ int dist)
+{
+ unsigned long faults, total_faults;
+
+ if (!p->numa_faults)
+ return 0;
+
+ total_faults = p->total_numa_faults;
+
+ if (!total_faults)
+ return 0;
+
+ faults = task_faults(p, nid);
+ faults += score_nearby_nodes(p, nid, dist, true);
+
+ return 1000 * faults / total_faults;
+}
+
+static inline unsigned long group_weight(struct task_struct *p, int nid,
+ int dist)
+{
+ struct numa_group *ng = deref_task_numa_group(p);
+ unsigned long faults, total_faults;
+
+ if (!ng)
+ return 0;
+
+ total_faults = ng->total_faults;
+
+ if (!total_faults)
+ return 0;
+
+ faults = group_faults(p, nid);
+ faults += score_nearby_nodes(p, nid, dist, false);
+
+ return 1000 * faults / total_faults;
+}
+
+bool should_numa_migrate_memory(struct task_struct *p, struct page * page,
+ int src_nid, int dst_cpu)
+{
+ struct numa_group *ng = deref_curr_numa_group(p);
+ int dst_nid = cpu_to_node(dst_cpu);
+ int last_cpupid, this_cpupid;
+
+ this_cpupid = cpu_pid_to_cpupid(dst_cpu, current->pid);
+ last_cpupid = page_cpupid_xchg_last(page, this_cpupid);
+
+ /*
+ * Allow first faults or private faults to migrate immediately early in
+ * the lifetime of a task. The magic number 4 is based on waiting for
+ * two full passes of the "multi-stage node selection" test that is
+ * executed below.
+ */
+ if ((p->numa_preferred_nid == NUMA_NO_NODE || p->numa_scan_seq <= 4) &&
+ (cpupid_pid_unset(last_cpupid) || cpupid_match_pid(p, last_cpupid)))
+ return true;
+
+ /*
+ * Multi-stage node selection is used in conjunction with a periodic
+ * migration fault to build a temporal task<->page relation. By using
+ * a two-stage filter we remove short/unlikely relations.
+ *
+ * Using P(p) ~ n_p / n_t as per frequentist probability, we can equate
+ * a task's usage of a particular page (n_p) per total usage of this
+ * page (n_t) (in a given time-span) to a probability.
+ *
+ * Our periodic faults will sample this probability and getting the
+ * same result twice in a row, given these samples are fully
+ * independent, is then given by P(n)^2, provided our sample period
+ * is sufficiently short compared to the usage pattern.
+ *
+ * This quadric squishes small probabilities, making it less likely we
+ * act on an unlikely task<->page relation.
+ */
+ if (!cpupid_pid_unset(last_cpupid) &&
+ cpupid_to_nid(last_cpupid) != dst_nid)
+ return false;
+
+ /* Always allow migrate on private faults */
+ if (cpupid_match_pid(p, last_cpupid))
+ return true;
+
+ /* A shared fault, but p->numa_group has not been set up yet. */
+ if (!ng)
+ return true;
+
+ /*
+ * Destination node is much more heavily used than the source
+ * node? Allow migration.
+ */
+ if (group_faults_cpu(ng, dst_nid) > group_faults_cpu(ng, src_nid) *
+ ACTIVE_NODE_FRACTION)
+ return true;
+
+ /*
+ * Distribute memory according to CPU & memory use on each node,
+ * with 3/4 hysteresis to avoid unnecessary memory migrations:
+ *
+ * faults_cpu(dst) 3 faults_cpu(src)
+ * --------------- * - > ---------------
+ * faults_mem(dst) 4 faults_mem(src)
+ */
+ return group_faults_cpu(ng, dst_nid) * group_faults(p, src_nid) * 3 >
+ group_faults_cpu(ng, src_nid) * group_faults(p, dst_nid) * 4;
+}
+
+static unsigned long cpu_runnable_load(struct rq *rq);
+
+/* Cached statistics for all CPUs within a node */
+struct numa_stats {
+ unsigned long load;
+
+ /* Total compute capacity of CPUs on a node */
+ unsigned long compute_capacity;
+};
+
+/*
+ * XXX borrowed from update_sg_lb_stats
+ */
+static void update_numa_stats(struct numa_stats *ns, int nid)
+{
+ int cpu;
+
+ memset(ns, 0, sizeof(*ns));
+ for_each_cpu(cpu, cpumask_of_node(nid)) {
+ struct rq *rq = cpu_rq(cpu);
+
+ ns->load += cpu_runnable_load(rq);
+ ns->compute_capacity += capacity_of(cpu);
+ }
+
+}
+
+struct task_numa_env {
+ struct task_struct *p;
+
+ int src_cpu, src_nid;
+ int dst_cpu, dst_nid;
+
+ struct numa_stats src_stats, dst_stats;
+
+ int imbalance_pct;
+ int dist;
+
+ struct task_struct *best_task;
+ long best_imp;
+ int best_cpu;
+};
+
+static void task_numa_assign(struct task_numa_env *env,
+ struct task_struct *p, long imp)
+{
+ struct rq *rq = cpu_rq(env->dst_cpu);
+
+ /* Bail out if run-queue part of active NUMA balance. */
+ if (xchg(&rq->numa_migrate_on, 1))
+ return;
+
+ /*
+ * Clear previous best_cpu/rq numa-migrate flag, since task now
+ * found a better CPU to move/swap.
+ */
+ if (env->best_cpu != -1) {
+ rq = cpu_rq(env->best_cpu);
+ WRITE_ONCE(rq->numa_migrate_on, 0);
+ }
+
+ if (env->best_task)
+ put_task_struct(env->best_task);
+ if (p)
+ get_task_struct(p);
+
+ env->best_task = p;
+ env->best_imp = imp;
+ env->best_cpu = env->dst_cpu;
+}
+
+static bool load_too_imbalanced(long src_load, long dst_load,
+ struct task_numa_env *env)
+{
+ long imb, old_imb;
+ long orig_src_load, orig_dst_load;
+ long src_capacity, dst_capacity;
+
+ /*
+ * The load is corrected for the CPU capacity available on each node.
+ *
+ * src_load dst_load
+ * ------------ vs ---------
+ * src_capacity dst_capacity
+ */
+ src_capacity = env->src_stats.compute_capacity;
+ dst_capacity = env->dst_stats.compute_capacity;
+
+ imb = abs(dst_load * src_capacity - src_load * dst_capacity);
+
+ orig_src_load = env->src_stats.load;
+ orig_dst_load = env->dst_stats.load;
+
+ old_imb = abs(orig_dst_load * src_capacity - orig_src_load * dst_capacity);
+
+ /* Would this change make things worse? */
+ return (imb > old_imb);
+}
+
+/*
+ * Maximum NUMA importance can be 1998 (2*999);
+ * SMALLIMP @ 30 would be close to 1998/64.
+ * Used to deter task migration.
+ */
+#define SMALLIMP 30
+
+/*
+ * This checks if the overall compute and NUMA accesses of the system would
+ * be improved if the source tasks was migrated to the target dst_cpu taking
+ * into account that it might be best if task running on the dst_cpu should
+ * be exchanged with the source task
+ */
+static void task_numa_compare(struct task_numa_env *env,
+ long taskimp, long groupimp, bool maymove)
+{
+ struct numa_group *cur_ng, *p_ng = deref_curr_numa_group(env->p);
+ struct rq *dst_rq = cpu_rq(env->dst_cpu);
+ long imp = p_ng ? groupimp : taskimp;
+ struct task_struct *cur;
+ long src_load, dst_load;
+ int dist = env->dist;
+ long moveimp = imp;
+ long load;
+
+ if (READ_ONCE(dst_rq->numa_migrate_on))
+ return;
+
+ rcu_read_lock();
+ cur = rcu_dereference(dst_rq->curr);
+ if (cur && ((cur->flags & PF_EXITING) || is_idle_task(cur)))
+ cur = NULL;
+
+ /*
+ * Because we have preemption enabled we can get migrated around and
+ * end try selecting ourselves (current == env->p) as a swap candidate.
+ */
+ if (cur == env->p)
+ goto unlock;
+
+ if (!cur) {
+ if (maymove && moveimp >= env->best_imp)
+ goto assign;
+ else
+ goto unlock;
+ }
+
+ /*
+ * "imp" is the fault differential for the source task between the
+ * source and destination node. Calculate the total differential for
+ * the source task and potential destination task. The more negative
+ * the value is, the more remote accesses that would be expected to
+ * be incurred if the tasks were swapped.
+ */
+ /* Skip this swap candidate if cannot move to the source cpu */
+ if (!cpumask_test_cpu(env->src_cpu, cur->cpus_ptr))
+ goto unlock;
+
+ /*
+ * If dst and source tasks are in the same NUMA group, or not
+ * in any group then look only at task weights.
+ */
+ cur_ng = rcu_dereference(cur->numa_group);
+ if (cur_ng == p_ng) {
+ imp = taskimp + task_weight(cur, env->src_nid, dist) -
+ task_weight(cur, env->dst_nid, dist);
+ /*
+ * Add some hysteresis to prevent swapping the
+ * tasks within a group over tiny differences.
+ */
+ if (cur_ng)
+ imp -= imp / 16;
+ } else {
+ /*
+ * Compare the group weights. If a task is all by itself
+ * (not part of a group), use the task weight instead.
+ */
+ if (cur_ng && p_ng)
+ imp += group_weight(cur, env->src_nid, dist) -
+ group_weight(cur, env->dst_nid, dist);
+ else
+ imp += task_weight(cur, env->src_nid, dist) -
+ task_weight(cur, env->dst_nid, dist);
+ }
+
+ if (maymove && moveimp > imp && moveimp > env->best_imp) {
+ imp = moveimp;
+ cur = NULL;
+ goto assign;
+ }
+
+ /*
+ * If the NUMA importance is less than SMALLIMP,
+ * task migration might only result in ping pong
+ * of tasks and also hurt performance due to cache
+ * misses.
+ */
+ if (imp < SMALLIMP || imp <= env->best_imp + SMALLIMP / 2)
+ goto unlock;
+
+ /*
+ * In the overloaded case, try and keep the load balanced.
+ */
+ load = task_h_load(env->p) - task_h_load(cur);
+ if (!load)
+ goto assign;
+
+ dst_load = env->dst_stats.load + load;
+ src_load = env->src_stats.load - load;
+
+ if (load_too_imbalanced(src_load, dst_load, env))
+ goto unlock;
+
+assign:
+ /*
+ * One idle CPU per node is evaluated for a task numa move.
+ * Call select_idle_sibling to maybe find a better one.
+ */
+ if (!cur) {
+ /*
+ * select_idle_siblings() uses an per-CPU cpumask that
+ * can be used from IRQ context.
+ */
+ local_irq_disable();
+ env->dst_cpu = select_idle_sibling(env->p, env->src_cpu,
+ env->dst_cpu);
+ local_irq_enable();
+ }
+
+ task_numa_assign(env, cur, imp);
+unlock:
+ rcu_read_unlock();
+}
+
+static void task_numa_find_cpu(struct task_numa_env *env,
+ long taskimp, long groupimp)
+{
+ long src_load, dst_load, load;
+ bool maymove = false;
+ int cpu;
+
+ load = task_h_load(env->p);
+ dst_load = env->dst_stats.load + load;
+ src_load = env->src_stats.load - load;
+
+ /*
+ * If the improvement from just moving env->p direction is better
+ * than swapping tasks around, check if a move is possible.
+ */
+ maymove = !load_too_imbalanced(src_load, dst_load, env);
+
+ for_each_cpu(cpu, cpumask_of_node(env->dst_nid)) {
+ /* Skip this CPU if the source task cannot migrate */
+ if (!cpumask_test_cpu(cpu, env->p->cpus_ptr))
+ continue;
+
+ env->dst_cpu = cpu;
+ task_numa_compare(env, taskimp, groupimp, maymove);
+ }
+}
+
+static int task_numa_migrate(struct task_struct *p)
+{
+ struct task_numa_env env = {
+ .p = p,
+
+ .src_cpu = task_cpu(p),
+ .src_nid = task_node(p),
+
+ .imbalance_pct = 112,
+
+ .best_task = NULL,
+ .best_imp = 0,
+ .best_cpu = -1,
+ };
+ unsigned long taskweight, groupweight;
+ struct sched_domain *sd;
+ long taskimp, groupimp;
+ struct numa_group *ng;
+ struct rq *best_rq;
+ int nid, ret, dist;
+
+ /*
+ * Pick the lowest SD_NUMA domain, as that would have the smallest
+ * imbalance and would be the first to start moving tasks about.
+ *
+ * And we want to avoid any moving of tasks about, as that would create
+ * random movement of tasks -- counter the numa conditions we're trying
+ * to satisfy here.
+ */
+ rcu_read_lock();
+ sd = rcu_dereference(per_cpu(sd_numa, env.src_cpu));
+ if (sd)
+ env.imbalance_pct = 100 + (sd->imbalance_pct - 100) / 2;
+ rcu_read_unlock();
+
+ /*
+ * Cpusets can break the scheduler domain tree into smaller
+ * balance domains, some of which do not cross NUMA boundaries.
+ * Tasks that are "trapped" in such domains cannot be migrated
+ * elsewhere, so there is no point in (re)trying.
+ */
+ if (unlikely(!sd)) {
+ sched_setnuma(p, task_node(p));
+ return -EINVAL;
+ }
+
+ env.dst_nid = p->numa_preferred_nid;
+ dist = env.dist = node_distance(env.src_nid, env.dst_nid);
+ taskweight = task_weight(p, env.src_nid, dist);
+ groupweight = group_weight(p, env.src_nid, dist);
+ update_numa_stats(&env.src_stats, env.src_nid);
+ taskimp = task_weight(p, env.dst_nid, dist) - taskweight;
+ groupimp = group_weight(p, env.dst_nid, dist) - groupweight;
+ update_numa_stats(&env.dst_stats, env.dst_nid);
+
+ /* Try to find a spot on the preferred nid. */
+ task_numa_find_cpu(&env, taskimp, groupimp);
+
+ /*
+ * Look at other nodes in these cases:
+ * - there is no space available on the preferred_nid
+ * - the task is part of a numa_group that is interleaved across
+ * multiple NUMA nodes; in order to better consolidate the group,
+ * we need to check other locations.
+ */
+ ng = deref_curr_numa_group(p);
+ if (env.best_cpu == -1 || (ng && ng->active_nodes > 1)) {
+ for_each_online_node(nid) {
+ if (nid == env.src_nid || nid == p->numa_preferred_nid)
+ continue;
+
+ dist = node_distance(env.src_nid, env.dst_nid);
+ if (sched_numa_topology_type == NUMA_BACKPLANE &&
+ dist != env.dist) {
+ taskweight = task_weight(p, env.src_nid, dist);
+ groupweight = group_weight(p, env.src_nid, dist);
+ }
+
+ /* Only consider nodes where both task and groups benefit */
+ taskimp = task_weight(p, nid, dist) - taskweight;
+ groupimp = group_weight(p, nid, dist) - groupweight;
+ if (taskimp < 0 && groupimp < 0)
+ continue;
+
+ env.dist = dist;
+ env.dst_nid = nid;
+ update_numa_stats(&env.dst_stats, env.dst_nid);
+ task_numa_find_cpu(&env, taskimp, groupimp);
+ }
+ }
+
+ /*
+ * If the task is part of a workload that spans multiple NUMA nodes,
+ * and is migrating into one of the workload's active nodes, remember
+ * this node as the task's preferred numa node, so the workload can
+ * settle down.
+ * A task that migrated to a second choice node will be better off
+ * trying for a better one later. Do not set the preferred node here.
+ */
+ if (ng) {
+ if (env.best_cpu == -1)
+ nid = env.src_nid;
+ else
+ nid = cpu_to_node(env.best_cpu);
+
+ if (nid != p->numa_preferred_nid)
+ sched_setnuma(p, nid);
+ }
+
+ /* No better CPU than the current one was found. */
+ if (env.best_cpu == -1)
+ return -EAGAIN;
+
+ best_rq = cpu_rq(env.best_cpu);
+ if (env.best_task == NULL) {
+ ret = migrate_task_to(p, env.best_cpu);
+ WRITE_ONCE(best_rq->numa_migrate_on, 0);
+ if (ret != 0)
+ trace_sched_stick_numa(p, env.src_cpu, env.best_cpu);
+ return ret;
+ }
+
+ ret = migrate_swap(p, env.best_task, env.best_cpu, env.src_cpu);
+ WRITE_ONCE(best_rq->numa_migrate_on, 0);
+
+ if (ret != 0)
+ trace_sched_stick_numa(p, env.src_cpu, task_cpu(env.best_task));
+ put_task_struct(env.best_task);
+ return ret;
+}
+
+/* Attempt to migrate a task to a CPU on the preferred node. */
+static void numa_migrate_preferred(struct task_struct *p)
+{
+ unsigned long interval = HZ;
+
+ /* This task has no NUMA fault statistics yet */
+ if (unlikely(p->numa_preferred_nid == NUMA_NO_NODE || !p->numa_faults))
+ return;
+
+ /* Periodically retry migrating the task to the preferred node */
+ interval = min(interval, msecs_to_jiffies(p->numa_scan_period) / 16);
+ p->numa_migrate_retry = jiffies + interval;
+
+ /* Success if task is already running on preferred CPU */
+ if (task_node(p) == p->numa_preferred_nid)
+ return;
+
+ /* Otherwise, try migrate to a CPU on the preferred node */
+ task_numa_migrate(p);
+}
+
+/*
+ * Find out how many nodes on the workload is actively running on. Do this by
+ * tracking the nodes from which NUMA hinting faults are triggered. This can
+ * be different from the set of nodes where the workload's memory is currently
+ * located.
+ */
+static void numa_group_count_active_nodes(struct numa_group *numa_group)
+{
+ unsigned long faults, max_faults = 0;
+ int nid, active_nodes = 0;
+
+ for_each_online_node(nid) {
+ faults = group_faults_cpu(numa_group, nid);
+ if (faults > max_faults)
+ max_faults = faults;
+ }
+
+ for_each_online_node(nid) {
+ faults = group_faults_cpu(numa_group, nid);
+ if (faults * ACTIVE_NODE_FRACTION > max_faults)
+ active_nodes++;
+ }
+
+ numa_group->max_faults_cpu = max_faults;
+ numa_group->active_nodes = active_nodes;
+}
+
+/*
+ * When adapting the scan rate, the period is divided into NUMA_PERIOD_SLOTS
+ * increments. The more local the fault statistics are, the higher the scan
+ * period will be for the next scan window. If local/(local+remote) ratio is
+ * below NUMA_PERIOD_THRESHOLD (where range of ratio is 1..NUMA_PERIOD_SLOTS)
+ * the scan period will decrease. Aim for 70% local accesses.
+ */
+#define NUMA_PERIOD_SLOTS 10
+#define NUMA_PERIOD_THRESHOLD 7
+
+/*
+ * Increase the scan period (slow down scanning) if the majority of
+ * our memory is already on our local node, or if the majority of
+ * the page accesses are shared with other processes.
+ * Otherwise, decrease the scan period.
+ */
+static void update_task_scan_period(struct task_struct *p,
+ unsigned long shared, unsigned long private)
+{
+ unsigned int period_slot;
+ int lr_ratio, ps_ratio;
+ int diff;
+
+ unsigned long remote = p->numa_faults_locality[0];
+ unsigned long local = p->numa_faults_locality[1];
+
+ /*
+ * If there were no record hinting faults then either the task is
+ * completely idle or all activity is areas that are not of interest
+ * to automatic numa balancing. Related to that, if there were failed
+ * migration then it implies we are migrating too quickly or the local
+ * node is overloaded. In either case, scan slower
+ */
+ if (local + shared == 0 || p->numa_faults_locality[2]) {
+ p->numa_scan_period = min(p->numa_scan_period_max,
+ p->numa_scan_period << 1);
+
+ p->mm->numa_next_scan = jiffies +
+ msecs_to_jiffies(p->numa_scan_period);
+
+ return;
+ }
+
+ /*
+ * Prepare to scale scan period relative to the current period.
+ * == NUMA_PERIOD_THRESHOLD scan period stays the same
+ * < NUMA_PERIOD_THRESHOLD scan period decreases (scan faster)
+ * >= NUMA_PERIOD_THRESHOLD scan period increases (scan slower)
+ */
+ period_slot = DIV_ROUND_UP(p->numa_scan_period, NUMA_PERIOD_SLOTS);
+ lr_ratio = (local * NUMA_PERIOD_SLOTS) / (local + remote);
+ ps_ratio = (private * NUMA_PERIOD_SLOTS) / (private + shared);
+
+ if (ps_ratio >= NUMA_PERIOD_THRESHOLD) {
+ /*
+ * Most memory accesses are local. There is no need to
+ * do fast NUMA scanning, since memory is already local.
+ */
+ int slot = ps_ratio - NUMA_PERIOD_THRESHOLD;
+ if (!slot)
+ slot = 1;
+ diff = slot * period_slot;
+ } else if (lr_ratio >= NUMA_PERIOD_THRESHOLD) {
+ /*
+ * Most memory accesses are shared with other tasks.
+ * There is no point in continuing fast NUMA scanning,
+ * since other tasks may just move the memory elsewhere.
+ */
+ int slot = lr_ratio - NUMA_PERIOD_THRESHOLD;
+ if (!slot)
+ slot = 1;
+ diff = slot * period_slot;
+ } else {
+ /*
+ * Private memory faults exceed (SLOTS-THRESHOLD)/SLOTS,
+ * yet they are not on the local NUMA node. Speed up
+ * NUMA scanning to get the memory moved over.
+ */
+ int ratio = max(lr_ratio, ps_ratio);
+ diff = -(NUMA_PERIOD_THRESHOLD - ratio) * period_slot;
+ }
+
+ p->numa_scan_period = clamp(p->numa_scan_period + diff,
+ task_scan_min(p), task_scan_max(p));
+ memset(p->numa_faults_locality, 0, sizeof(p->numa_faults_locality));
+}
+
+/*
+ * Get the fraction of time the task has been running since the last
+ * NUMA placement cycle. The scheduler keeps similar statistics, but
+ * decays those on a 32ms period, which is orders of magnitude off
+ * from the dozens-of-seconds NUMA balancing period. Use the scheduler
+ * stats only if the task is so new there are no NUMA statistics yet.
+ */
+static u64 numa_get_avg_runtime(struct task_struct *p, u64 *period)
+{
+ u64 runtime, delta, now;
+ /* Use the start of this time slice to avoid calculations. */
+ now = p->se.exec_start;
+ runtime = p->se.sum_exec_runtime;
+
+ if (p->last_task_numa_placement) {
+ delta = runtime - p->last_sum_exec_runtime;
+ *period = now - p->last_task_numa_placement;
+
+ /* Avoid time going backwards, prevent potential divide error: */
+ if (unlikely((s64)*period < 0))
+ *period = 0;
+ } else {
+ delta = p->se.avg.load_sum;
+ *period = LOAD_AVG_MAX;
+ }
+
+ p->last_sum_exec_runtime = runtime;
+ p->last_task_numa_placement = now;
+
+ return delta;
+}
+
+/*
+ * Determine the preferred nid for a task in a numa_group. This needs to
+ * be done in a way that produces consistent results with group_weight,
+ * otherwise workloads might not converge.
+ */
+static int preferred_group_nid(struct task_struct *p, int nid)
+{
+ nodemask_t nodes;
+ int dist;
+
+ /* Direct connections between all NUMA nodes. */
+ if (sched_numa_topology_type == NUMA_DIRECT)
+ return nid;
+
+ /*
+ * On a system with glueless mesh NUMA topology, group_weight
+ * scores nodes according to the number of NUMA hinting faults on
+ * both the node itself, and on nearby nodes.
+ */
+ if (sched_numa_topology_type == NUMA_GLUELESS_MESH) {
+ unsigned long score, max_score = 0;
+ int node, max_node = nid;
+
+ dist = sched_max_numa_distance;
+
+ for_each_online_node(node) {
+ score = group_weight(p, node, dist);
+ if (score > max_score) {
+ max_score = score;
+ max_node = node;
+ }
+ }
+ return max_node;
+ }
+
+ /*
+ * Finding the preferred nid in a system with NUMA backplane
+ * interconnect topology is more involved. The goal is to locate
+ * tasks from numa_groups near each other in the system, and
+ * untangle workloads from different sides of the system. This requires
+ * searching down the hierarchy of node groups, recursively searching
+ * inside the highest scoring group of nodes. The nodemask tricks
+ * keep the complexity of the search down.
+ */
+ nodes = node_online_map;
+ for (dist = sched_max_numa_distance; dist > LOCAL_DISTANCE; dist--) {
+ unsigned long max_faults = 0;
+ nodemask_t max_group = NODE_MASK_NONE;
+ int a, b;
+
+ /* Are there nodes at this distance from each other? */
+ if (!find_numa_distance(dist))
+ continue;
+
+ for_each_node_mask(a, nodes) {
+ unsigned long faults = 0;
+ nodemask_t this_group;
+ nodes_clear(this_group);
+
+ /* Sum group's NUMA faults; includes a==b case. */
+ for_each_node_mask(b, nodes) {
+ if (node_distance(a, b) < dist) {
+ faults += group_faults(p, b);
+ node_set(b, this_group);
+ node_clear(b, nodes);
+ }
+ }
+
+ /* Remember the top group. */
+ if (faults > max_faults) {
+ max_faults = faults;
+ max_group = this_group;
+ /*
+ * subtle: at the smallest distance there is
+ * just one node left in each "group", the
+ * winner is the preferred nid.
+ */
+ nid = a;
+ }
+ }
+ /* Next round, evaluate the nodes within max_group. */
+ if (!max_faults)
+ break;
+ nodes = max_group;
+ }
+ return nid;
+}
+
+static void task_numa_placement(struct task_struct *p)
+{
+ int seq, nid, max_nid = NUMA_NO_NODE;
+ unsigned long max_faults = 0;
+ unsigned long fault_types[2] = { 0, 0 };
+ unsigned long total_faults;
+ u64 runtime, period;
+ spinlock_t *group_lock = NULL;
+ struct numa_group *ng;
+
+ /*
+ * The p->mm->numa_scan_seq field gets updated without
+ * exclusive access. Use READ_ONCE() here to ensure
+ * that the field is read in a single access:
+ */
+ seq = READ_ONCE(p->mm->numa_scan_seq);
+ if (p->numa_scan_seq == seq)
+ return;
+ p->numa_scan_seq = seq;
+ p->numa_scan_period_max = task_scan_max(p);
+
+ total_faults = p->numa_faults_locality[0] +
+ p->numa_faults_locality[1];
+ runtime = numa_get_avg_runtime(p, &period);
+
+ /* If the task is part of a group prevent parallel updates to group stats */
+ ng = deref_curr_numa_group(p);
+ if (ng) {
+ group_lock = &ng->lock;
+ spin_lock_irq(group_lock);
+ }
+
+ /* Find the node with the highest number of faults */
+ for_each_online_node(nid) {
+ /* Keep track of the offsets in numa_faults array */
+ int mem_idx, membuf_idx, cpu_idx, cpubuf_idx;
+ unsigned long faults = 0, group_faults = 0;
+ int priv;
+
+ for (priv = 0; priv < NR_NUMA_HINT_FAULT_TYPES; priv++) {
+ long diff, f_diff, f_weight;
+
+ mem_idx = task_faults_idx(NUMA_MEM, nid, priv);
+ membuf_idx = task_faults_idx(NUMA_MEMBUF, nid, priv);
+ cpu_idx = task_faults_idx(NUMA_CPU, nid, priv);
+ cpubuf_idx = task_faults_idx(NUMA_CPUBUF, nid, priv);
+
+ /* Decay existing window, copy faults since last scan */
+ diff = p->numa_faults[membuf_idx] - p->numa_faults[mem_idx] / 2;
+ fault_types[priv] += p->numa_faults[membuf_idx];
+ p->numa_faults[membuf_idx] = 0;
+
+ /*
+ * Normalize the faults_from, so all tasks in a group
+ * count according to CPU use, instead of by the raw
+ * number of faults. Tasks with little runtime have
+ * little over-all impact on throughput, and thus their
+ * faults are less important.
+ */
+ f_weight = div64_u64(runtime << 16, period + 1);
+ f_weight = (f_weight * p->numa_faults[cpubuf_idx]) /
+ (total_faults + 1);
+ f_diff = f_weight - p->numa_faults[cpu_idx] / 2;
+ p->numa_faults[cpubuf_idx] = 0;
+
+ p->numa_faults[mem_idx] += diff;
+ p->numa_faults[cpu_idx] += f_diff;
+ faults += p->numa_faults[mem_idx];
+ p->total_numa_faults += diff;
+ if (ng) {
+ /*
+ * safe because we can only change our own group
+ *
+ * mem_idx represents the offset for a given
+ * nid and priv in a specific region because it
+ * is at the beginning of the numa_faults array.
+ */
+ ng->faults[mem_idx] += diff;
+ ng->faults_cpu[mem_idx] += f_diff;
+ ng->total_faults += diff;
+ group_faults += ng->faults[mem_idx];
+ }
+ }
+
+ if (!ng) {
+ if (faults > max_faults) {
+ max_faults = faults;
+ max_nid = nid;
+ }
+ } else if (group_faults > max_faults) {
+ max_faults = group_faults;
+ max_nid = nid;
+ }
+ }
+
+ if (ng) {
+ numa_group_count_active_nodes(ng);
+ spin_unlock_irq(group_lock);
+ max_nid = preferred_group_nid(p, max_nid);
+ }
+
+ if (max_faults) {
+ /* Set the new preferred node */
+ if (max_nid != p->numa_preferred_nid)
+ sched_setnuma(p, max_nid);
+ }
+
+ update_task_scan_period(p, fault_types[0], fault_types[1]);
+}
+
+static inline int get_numa_group(struct numa_group *grp)
+{
+ return refcount_inc_not_zero(&grp->refcount);
+}
+
+static inline void put_numa_group(struct numa_group *grp)
+{
+ if (refcount_dec_and_test(&grp->refcount))
+ kfree_rcu(grp, rcu);
+}
+
+static void task_numa_group(struct task_struct *p, int cpupid, int flags,
+ int *priv)
+{
+ struct numa_group *grp, *my_grp;
+ struct task_struct *tsk;
+ bool join = false;
+ int cpu = cpupid_to_cpu(cpupid);
+ int i;
+
+ if (unlikely(!deref_curr_numa_group(p))) {
+ unsigned int size = sizeof(struct numa_group) +
+ 4*nr_node_ids*sizeof(unsigned long);
+
+ grp = kzalloc(size, GFP_KERNEL | __GFP_NOWARN);
+ if (!grp)
+ return;
+
+ refcount_set(&grp->refcount, 1);
+ grp->active_nodes = 1;
+ grp->max_faults_cpu = 0;
+ spin_lock_init(&grp->lock);
+ grp->gid = p->pid;
+ /* Second half of the array tracks nids where faults happen */
+ grp->faults_cpu = grp->faults + NR_NUMA_HINT_FAULT_TYPES *
+ nr_node_ids;
+
+ for (i = 0; i < NR_NUMA_HINT_FAULT_STATS * nr_node_ids; i++)
+ grp->faults[i] = p->numa_faults[i];
+
+ grp->total_faults = p->total_numa_faults;
+
+ grp->nr_tasks++;
+ rcu_assign_pointer(p->numa_group, grp);
+ }
+
+ rcu_read_lock();
+ tsk = READ_ONCE(cpu_rq(cpu)->curr);
+
+ if (!cpupid_match_pid(tsk, cpupid))
+ goto no_join;
+
+ grp = rcu_dereference(tsk->numa_group);
+ if (!grp)
+ goto no_join;
+
+ my_grp = deref_curr_numa_group(p);
+ if (grp == my_grp)
+ goto no_join;
+
+ /*
+ * Only join the other group if its bigger; if we're the bigger group,
+ * the other task will join us.
+ */
+ if (my_grp->nr_tasks > grp->nr_tasks)
+ goto no_join;
+
+ /*
+ * Tie-break on the grp address.
+ */
+ if (my_grp->nr_tasks == grp->nr_tasks && my_grp > grp)
+ goto no_join;
+
+ /* Always join threads in the same process. */
+ if (tsk->mm == current->mm)
+ join = true;
+
+ /* Simple filter to avoid false positives due to PID collisions */
+ if (flags & TNF_SHARED)
+ join = true;
+
+ /* Update priv based on whether false sharing was detected */
+ *priv = !join;
+
+ if (join && !get_numa_group(grp))
+ goto no_join;
+
+ rcu_read_unlock();
+
+ if (!join)
+ return;
+
+ BUG_ON(irqs_disabled());
+ double_lock_irq(&my_grp->lock, &grp->lock);
+
+ for (i = 0; i < NR_NUMA_HINT_FAULT_STATS * nr_node_ids; i++) {
+ my_grp->faults[i] -= p->numa_faults[i];
+ grp->faults[i] += p->numa_faults[i];
+ }
+ my_grp->total_faults -= p->total_numa_faults;
+ grp->total_faults += p->total_numa_faults;
+
+ my_grp->nr_tasks--;
+ grp->nr_tasks++;
+
+ spin_unlock(&my_grp->lock);
+ spin_unlock_irq(&grp->lock);
+
+ rcu_assign_pointer(p->numa_group, grp);
+
+ put_numa_group(my_grp);
+ return;
+
+no_join:
+ rcu_read_unlock();
+ return;
+}
+
+/*
+ * Get rid of NUMA staticstics associated with a task (either current or dead).
+ * If @final is set, the task is dead and has reached refcount zero, so we can
+ * safely free all relevant data structures. Otherwise, there might be
+ * concurrent reads from places like load balancing and procfs, and we should
+ * reset the data back to default state without freeing ->numa_faults.
+ */
+void task_numa_free(struct task_struct *p, bool final)
+{
+ /* safe: p either is current or is being freed by current */
+ struct numa_group *grp = rcu_dereference_raw(p->numa_group);
+ unsigned long *numa_faults = p->numa_faults;
+ unsigned long flags;
+ int i;
+
+ if (!numa_faults)
+ return;
+
+ if (grp) {
+ spin_lock_irqsave(&grp->lock, flags);
+ for (i = 0; i < NR_NUMA_HINT_FAULT_STATS * nr_node_ids; i++)
+ grp->faults[i] -= p->numa_faults[i];
+ grp->total_faults -= p->total_numa_faults;
+
+ grp->nr_tasks--;
+ spin_unlock_irqrestore(&grp->lock, flags);
+ RCU_INIT_POINTER(p->numa_group, NULL);
+ put_numa_group(grp);
+ }
+
+ if (final) {
+ p->numa_faults = NULL;
+ kfree(numa_faults);
+ } else {
+ p->total_numa_faults = 0;
+ for (i = 0; i < NR_NUMA_HINT_FAULT_STATS * nr_node_ids; i++)
+ numa_faults[i] = 0;
+ }
+}
+
+/*
+ * Got a PROT_NONE fault for a page on @node.
+ */
+void task_numa_fault(int last_cpupid, int mem_node, int pages, int flags)
+{
+ struct task_struct *p = current;
+ bool migrated = flags & TNF_MIGRATED;
+ int cpu_node = task_node(current);
+ int local = !!(flags & TNF_FAULT_LOCAL);
+ struct numa_group *ng;
+ int priv;
+
+ if (!static_branch_likely(&sched_numa_balancing))
+ return;
+
+ /* for example, ksmd faulting in a user's mm */
+ if (!p->mm)
+ return;
+
+ /* Allocate buffer to track faults on a per-node basis */
+ if (unlikely(!p->numa_faults)) {
+ int size = sizeof(*p->numa_faults) *
+ NR_NUMA_HINT_FAULT_BUCKETS * nr_node_ids;
+
+ p->numa_faults = kzalloc(size, GFP_KERNEL|__GFP_NOWARN);
+ if (!p->numa_faults)
+ return;
+
+ p->total_numa_faults = 0;
+ memset(p->numa_faults_locality, 0, sizeof(p->numa_faults_locality));
+ }
+
+ /*
+ * First accesses are treated as private, otherwise consider accesses
+ * to be private if the accessing pid has not changed
+ */
+ if (unlikely(last_cpupid == (-1 & LAST_CPUPID_MASK))) {
+ priv = 1;
+ } else {
+ priv = cpupid_match_pid(p, last_cpupid);
+ if (!priv && !(flags & TNF_NO_GROUP))
+ task_numa_group(p, last_cpupid, flags, &priv);
+ }
+
+ /*
+ * If a workload spans multiple NUMA nodes, a shared fault that
+ * occurs wholly within the set of nodes that the workload is
+ * actively using should be counted as local. This allows the
+ * scan rate to slow down when a workload has settled down.
+ */
+ ng = deref_curr_numa_group(p);
+ if (!priv && !local && ng && ng->active_nodes > 1 &&
+ numa_is_active_node(cpu_node, ng) &&
+ numa_is_active_node(mem_node, ng))
+ local = 1;
+
+ /*
+ * Retry to migrate task to preferred node periodically, in case it
+ * previously failed, or the scheduler moved us.
+ */
+ if (time_after(jiffies, p->numa_migrate_retry)) {
+ task_numa_placement(p);
+ numa_migrate_preferred(p);
+ }
+
+ if (migrated)
+ p->numa_pages_migrated += pages;
+ if (flags & TNF_MIGRATE_FAIL)
+ p->numa_faults_locality[2] += pages;
+
+ p->numa_faults[task_faults_idx(NUMA_MEMBUF, mem_node, priv)] += pages;
+ p->numa_faults[task_faults_idx(NUMA_CPUBUF, cpu_node, priv)] += pages;
+ p->numa_faults_locality[local] += pages;
+}
+
+static void reset_ptenuma_scan(struct task_struct *p)
+{
+ /*
+ * We only did a read acquisition of the mmap sem, so
+ * p->mm->numa_scan_seq is written to without exclusive access
+ * and the update is not guaranteed to be atomic. That's not
+ * much of an issue though, since this is just used for
+ * statistical sampling. Use READ_ONCE/WRITE_ONCE, which are not
+ * expensive, to avoid any form of compiler optimizations:
+ */
+ WRITE_ONCE(p->mm->numa_scan_seq, READ_ONCE(p->mm->numa_scan_seq) + 1);
+ p->mm->numa_scan_offset = 0;
+}
+
+/*
+ * The expensive part of numa migration is done from task_work context.
+ * Triggered from task_tick_numa().
+ */
+static void task_numa_work(struct callback_head *work)
+{
+ unsigned long migrate, next_scan, now = jiffies;
+ struct task_struct *p = current;
+ struct mm_struct *mm = p->mm;
+ u64 runtime = p->se.sum_exec_runtime;
+ struct vm_area_struct *vma;
+ unsigned long start, end;
+ unsigned long nr_pte_updates = 0;
+ long pages, virtpages;
+
+ SCHED_WARN_ON(p != container_of(work, struct task_struct, numa_work));
+
+ work->next = work;
+ /*
+ * Who cares about NUMA placement when they're dying.
+ *
+ * NOTE: make sure not to dereference p->mm before this check,
+ * exit_task_work() happens _after_ exit_mm() so we could be called
+ * without p->mm even though we still had it when we enqueued this
+ * work.
+ */
+ if (p->flags & PF_EXITING)
+ return;
+
+ if (!mm->numa_next_scan) {
+ mm->numa_next_scan = now +
+ msecs_to_jiffies(sysctl_numa_balancing_scan_delay);
+ }
+
+ /*
+ * Enforce maximal scan/migration frequency..
+ */
+ migrate = mm->numa_next_scan;
+ if (time_before(now, migrate))
+ return;
+
+ if (p->numa_scan_period == 0) {
+ p->numa_scan_period_max = task_scan_max(p);
+ p->numa_scan_period = task_scan_start(p);
+ }
+
+ next_scan = now + msecs_to_jiffies(p->numa_scan_period);
+ if (cmpxchg(&mm->numa_next_scan, migrate, next_scan) != migrate)
+ return;
+
+ /*
+ * Delay this task enough that another task of this mm will likely win
+ * the next time around.
+ */
+ p->node_stamp += 2 * TICK_NSEC;
+
+ start = mm->numa_scan_offset;
+ pages = sysctl_numa_balancing_scan_size;
+ pages <<= 20 - PAGE_SHIFT; /* MB in pages */
+ virtpages = pages * 8; /* Scan up to this much virtual space */
+ if (!pages)
+ return;
+
+
+ if (!down_read_trylock(&mm->mmap_sem))
+ return;
+ vma = find_vma(mm, start);
+ if (!vma) {
+ reset_ptenuma_scan(p);
+ start = 0;
+ vma = mm->mmap;
+ }
+ for (; vma; vma = vma->vm_next) {
+ if (!vma_migratable(vma) || !vma_policy_mof(vma) ||
+ is_vm_hugetlb_page(vma) || (vma->vm_flags & VM_MIXEDMAP)) {
+ continue;
+ }
+
+ /*
+ * Shared library pages mapped by multiple processes are not
+ * migrated as it is expected they are cache replicated. Avoid
+ * hinting faults in read-only file-backed mappings or the vdso
+ * as migrating the pages will be of marginal benefit.
+ */
+ if (!vma->vm_mm ||
+ (vma->vm_file && (vma->vm_flags & (VM_READ|VM_WRITE)) == (VM_READ)))
+ continue;
+
+ /*
+ * Skip inaccessible VMAs to avoid any confusion between
+ * PROT_NONE and NUMA hinting ptes
+ */
+ if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)))
+ continue;
+
+ do {
+ start = max(start, vma->vm_start);
+ end = ALIGN(start + (pages << PAGE_SHIFT), HPAGE_SIZE);
+ end = min(end, vma->vm_end);
+ nr_pte_updates = change_prot_numa(vma, start, end);
+
+ /*
+ * Try to scan sysctl_numa_balancing_size worth of
+ * hpages that have at least one present PTE that
+ * is not already pte-numa. If the VMA contains
+ * areas that are unused or already full of prot_numa
+ * PTEs, scan up to virtpages, to skip through those
+ * areas faster.
+ */
+ if (nr_pte_updates)
+ pages -= (end - start) >> PAGE_SHIFT;
+ virtpages -= (end - start) >> PAGE_SHIFT;
+
+ start = end;
+ if (pages <= 0 || virtpages <= 0)
+ goto out;
+
+ cond_resched();
+ } while (end != vma->vm_end);
+ }
+
+out:
+ /*
+ * It is possible to reach the end of the VMA list but the last few
+ * VMAs are not guaranteed to the vma_migratable. If they are not, we
+ * would find the !migratable VMA on the next scan but not reset the
+ * scanner to the start so check it now.
+ */
+ if (vma)
+ mm->numa_scan_offset = start;
+ else
+ reset_ptenuma_scan(p);
+ up_read(&mm->mmap_sem);
+
+ /*
+ * Make sure tasks use at least 32x as much time to run other code
+ * than they used here, to limit NUMA PTE scanning overhead to 3% max.
+ * Usually update_task_scan_period slows down scanning enough; on an
+ * overloaded system we need to limit overhead on a per task basis.
+ */
+ if (unlikely(p->se.sum_exec_runtime != runtime)) {
+ u64 diff = p->se.sum_exec_runtime - runtime;
+ p->node_stamp += 32 * diff;
+ }
+}
+
+void init_numa_balancing(unsigned long clone_flags, struct task_struct *p)
+{
+ int mm_users = 0;
+ struct mm_struct *mm = p->mm;
+
+ if (mm) {
+ mm_users = atomic_read(&mm->mm_users);
+ if (mm_users == 1) {
+ mm->numa_next_scan = jiffies + msecs_to_jiffies(sysctl_numa_balancing_scan_delay);
+ mm->numa_scan_seq = 0;
+ }
+ }
+ p->node_stamp = 0;
+ p->numa_scan_seq = mm ? mm->numa_scan_seq : 0;
+ p->numa_scan_period = sysctl_numa_balancing_scan_delay;
+ /* Protect against double add, see task_tick_numa and task_numa_work */
+ p->numa_work.next = &p->numa_work;
+ p->numa_faults = NULL;
+ RCU_INIT_POINTER(p->numa_group, NULL);
+ p->last_task_numa_placement = 0;
+ p->last_sum_exec_runtime = 0;
+
+ init_task_work(&p->numa_work, task_numa_work);
+
+ /* New address space, reset the preferred nid */
+ if (!(clone_flags & CLONE_VM)) {
+ p->numa_preferred_nid = NUMA_NO_NODE;
+ return;
+ }
+
+ /*
+ * New thread, keep existing numa_preferred_nid which should be copied
+ * already by arch_dup_task_struct but stagger when scans start.
+ */
+ if (mm) {
+ unsigned int delay;
+
+ delay = min_t(unsigned int, task_scan_max(current),
+ current->numa_scan_period * mm_users * NSEC_PER_MSEC);
+ delay += 2 * TICK_NSEC;
+ p->node_stamp = delay;
+ }
+}
+
+/*
+ * Drive the periodic memory faults..
+ */
+static void task_tick_numa(struct rq *rq, struct task_struct *curr)
+{
+ struct callback_head *work = &curr->numa_work;
+ u64 period, now;
+
+ /*
+ * We don't care about NUMA placement if we don't have memory.
+ */
+ if ((curr->flags & (PF_EXITING | PF_KTHREAD)) || work->next != work)
+ return;
+
+ /*
+ * Using runtime rather than walltime has the dual advantage that
+ * we (mostly) drive the selection from busy threads and that the
+ * task needs to have done some actual work before we bother with
+ * NUMA placement.
+ */
+ now = curr->se.sum_exec_runtime;
+ period = (u64)curr->numa_scan_period * NSEC_PER_MSEC;
+
+ if (now > curr->node_stamp + period) {
+ if (!curr->node_stamp)
+ curr->numa_scan_period = task_scan_start(curr);
+ curr->node_stamp += period;
+
+ if (!time_before(jiffies, curr->mm->numa_next_scan))
+ task_work_add(curr, work, true);
+ }
+}
+
+static void update_scan_period(struct task_struct *p, int new_cpu)
+{
+ int src_nid = cpu_to_node(task_cpu(p));
+ int dst_nid = cpu_to_node(new_cpu);
+
+ if (!static_branch_likely(&sched_numa_balancing))
+ return;
+
+ if (!p->mm || !p->numa_faults || (p->flags & PF_EXITING))
+ return;
+
+ if (src_nid == dst_nid)
+ return;
+
+ /*
+ * Allow resets if faults have been trapped before one scan
+ * has completed. This is most likely due to a new task that
+ * is pulled cross-node due to wakeups or load balancing.
+ */
+ if (p->numa_scan_seq) {
+ /*
+ * Avoid scan adjustments if moving to the preferred
+ * node or if the task was not previously running on
+ * the preferred node.
+ */
+ if (dst_nid == p->numa_preferred_nid ||
+ (p->numa_preferred_nid != NUMA_NO_NODE &&
+ src_nid != p->numa_preferred_nid))
+ return;
+ }
+
+ p->numa_scan_period = task_scan_start(p);
+}
+
+#else
+static void task_tick_numa(struct rq *rq, struct task_struct *curr)
+{
+}
+
+static inline void account_numa_enqueue(struct rq *rq, struct task_struct *p)
+{
+}
+
+static inline void account_numa_dequeue(struct rq *rq, struct task_struct *p)
+{
+}
+
+static inline void update_scan_period(struct task_struct *p, int new_cpu)
+{
+}
+
+#endif /* CONFIG_NUMA_BALANCING */
+
+static void
+account_entity_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+ update_load_add(&cfs_rq->load, se->load.weight);
+#ifdef CONFIG_SMP
+ if (entity_is_task(se)) {
+ struct rq *rq = rq_of(cfs_rq);
+
+ account_numa_enqueue(rq, task_of(se));
+ list_add(&se->group_node, &rq->cfs_tasks);
+ }
+#endif
+ cfs_rq->nr_running++;
+}
+
+static void
+account_entity_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+ update_load_sub(&cfs_rq->load, se->load.weight);
+#ifdef CONFIG_SMP
+ if (entity_is_task(se)) {
+ account_numa_dequeue(rq_of(cfs_rq), task_of(se));
+ list_del_init(&se->group_node);
+ }
+#endif
+ cfs_rq->nr_running--;
+}
+
+/*
+ * Signed add and clamp on underflow.
+ *
+ * Explicitly do a load-store to ensure the intermediate value never hits
+ * memory. This allows lockless observations without ever seeing the negative
+ * values.
+ */
+#define add_positive(_ptr, _val) do { \
+ typeof(_ptr) ptr = (_ptr); \
+ typeof(_val) val = (_val); \
+ typeof(*ptr) res, var = READ_ONCE(*ptr); \
+ \
+ res = var + val; \
+ \
+ if (val < 0 && res > var) \
+ res = 0; \
+ \
+ WRITE_ONCE(*ptr, res); \
+} while (0)
+
+/*
+ * Unsigned subtract and clamp on underflow.
+ *
+ * Explicitly do a load-store to ensure the intermediate value never hits
+ * memory. This allows lockless observations without ever seeing the negative
+ * values.
+ */
+#define sub_positive(_ptr, _val) do { \
+ typeof(_ptr) ptr = (_ptr); \
+ typeof(*ptr) val = (_val); \
+ typeof(*ptr) res, var = READ_ONCE(*ptr); \
+ res = var - val; \
+ if (res > var) \
+ res = 0; \
+ WRITE_ONCE(*ptr, res); \
+} while (0)
+
+/*
+ * Remove and clamp on negative, from a local variable.
+ *
+ * A variant of sub_positive(), which does not use explicit load-store
+ * and is thus optimized for local variable updates.
+ */
+#define lsub_positive(_ptr, _val) do { \
+ typeof(_ptr) ptr = (_ptr); \
+ *ptr -= min_t(typeof(*ptr), *ptr, _val); \
+} while (0)
+
+#ifdef CONFIG_SMP
+static inline void
+enqueue_runnable_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+ cfs_rq->runnable_weight += se->runnable_weight;
+
+ cfs_rq->avg.runnable_load_avg += se->avg.runnable_load_avg;
+ cfs_rq->avg.runnable_load_sum += se_runnable(se) * se->avg.runnable_load_sum;
+}
+
+static inline void
+dequeue_runnable_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+ cfs_rq->runnable_weight -= se->runnable_weight;
+
+ sub_positive(&cfs_rq->avg.runnable_load_avg, se->avg.runnable_load_avg);
+ sub_positive(&cfs_rq->avg.runnable_load_sum,
+ se_runnable(se) * se->avg.runnable_load_sum);
+}
+
+static inline void
+enqueue_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+ cfs_rq->avg.load_avg += se->avg.load_avg;
+ cfs_rq->avg.load_sum += se_weight(se) * se->avg.load_sum;
+}
+
+static inline void
+dequeue_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+ sub_positive(&cfs_rq->avg.load_avg, se->avg.load_avg);
+ sub_positive(&cfs_rq->avg.load_sum, se_weight(se) * se->avg.load_sum);
+}
+#else
+static inline void
+enqueue_runnable_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) { }
+static inline void
+dequeue_runnable_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) { }
+static inline void
+enqueue_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) { }
+static inline void
+dequeue_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) { }
+#endif
+
+static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se,
+ unsigned long weight, unsigned long runnable)
+{
+ if (se->on_rq) {
+ /* commit outstanding execution time */
+ if (cfs_rq->curr == se)
+ update_curr(cfs_rq);
+ account_entity_dequeue(cfs_rq, se);
+ dequeue_runnable_load_avg(cfs_rq, se);
+ }
+ dequeue_load_avg(cfs_rq, se);
+
+ se->runnable_weight = runnable;
+ update_load_set(&se->load, weight);
+
+#ifdef CONFIG_SMP
+ do {
+ u32 divider = LOAD_AVG_MAX - 1024 + se->avg.period_contrib;
+
+ se->avg.load_avg = div_u64(se_weight(se) * se->avg.load_sum, divider);
+ se->avg.runnable_load_avg =
+ div_u64(se_runnable(se) * se->avg.runnable_load_sum, divider);
+ } while (0);
+#endif
+
+ enqueue_load_avg(cfs_rq, se);
+ if (se->on_rq) {
+ account_entity_enqueue(cfs_rq, se);
+ enqueue_runnable_load_avg(cfs_rq, se);
+ }
+}
+
+void reweight_task(struct task_struct *p, int prio)
+{
+ struct sched_entity *se = &p->se;
+ struct cfs_rq *cfs_rq = cfs_rq_of(se);
+ struct load_weight *load = &se->load;
+ unsigned long weight = scale_load(sched_prio_to_weight[prio]);
+
+ reweight_entity(cfs_rq, se, weight, weight);
+ load->inv_weight = sched_prio_to_wmult[prio];
+}
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+#ifdef CONFIG_SMP
+/*
+ * All this does is approximate the hierarchical proportion which includes that
+ * global sum we all love to hate.
+ *
+ * That is, the weight of a group entity, is the proportional share of the
+ * group weight based on the group runqueue weights. That is:
+ *
+ * tg->weight * grq->load.weight
+ * ge->load.weight = ----------------------------- (1)
+ * \Sum grq->load.weight
+ *
+ * Now, because computing that sum is prohibitively expensive to compute (been
+ * there, done that) we approximate it with this average stuff. The average
+ * moves slower and therefore the approximation is cheaper and more stable.
+ *
+ * So instead of the above, we substitute:
+ *
+ * grq->load.weight -> grq->avg.load_avg (2)
+ *
+ * which yields the following:
+ *
+ * tg->weight * grq->avg.load_avg
+ * ge->load.weight = ------------------------------ (3)
+ * tg->load_avg
+ *
+ * Where: tg->load_avg ~= \Sum grq->avg.load_avg
+ *
+ * That is shares_avg, and it is right (given the approximation (2)).
+ *
+ * The problem with it is that because the average is slow -- it was designed
+ * to be exactly that of course -- this leads to transients in boundary
+ * conditions. In specific, the case where the group was idle and we start the
+ * one task. It takes time for our CPU's grq->avg.load_avg to build up,
+ * yielding bad latency etc..
+ *
+ * Now, in that special case (1) reduces to:
+ *
+ * tg->weight * grq->load.weight
+ * ge->load.weight = ----------------------------- = tg->weight (4)
+ * grp->load.weight
+ *
+ * That is, the sum collapses because all other CPUs are idle; the UP scenario.
+ *
+ * So what we do is modify our approximation (3) to approach (4) in the (near)
+ * UP case, like:
+ *
+ * ge->load.weight =
+ *
+ * tg->weight * grq->load.weight
+ * --------------------------------------------------- (5)
+ * tg->load_avg - grq->avg.load_avg + grq->load.weight
+ *
+ * But because grq->load.weight can drop to 0, resulting in a divide by zero,
+ * we need to use grq->avg.load_avg as its lower bound, which then gives:
+ *
+ *
+ * tg->weight * grq->load.weight
+ * ge->load.weight = ----------------------------- (6)
+ * tg_load_avg'
+ *
+ * Where:
+ *
+ * tg_load_avg' = tg->load_avg - grq->avg.load_avg +
+ * max(grq->load.weight, grq->avg.load_avg)
+ *
+ * And that is shares_weight and is icky. In the (near) UP case it approaches
+ * (4) while in the normal case it approaches (3). It consistently
+ * overestimates the ge->load.weight and therefore:
+ *
+ * \Sum ge->load.weight >= tg->weight
+ *
+ * hence icky!
+ */
+static long calc_group_shares(struct cfs_rq *cfs_rq)
+{
+ long tg_weight, tg_shares, load, shares;
+ struct task_group *tg = cfs_rq->tg;
+
+ tg_shares = READ_ONCE(tg->shares);
+
+ load = max(scale_load_down(cfs_rq->load.weight), cfs_rq->avg.load_avg);
+
+ tg_weight = atomic_long_read(&tg->load_avg);
+
+ /* Ensure tg_weight >= load */
+ tg_weight -= cfs_rq->tg_load_avg_contrib;
+ tg_weight += load;
+
+ shares = (tg_shares * load);
+ if (tg_weight)
+ shares /= tg_weight;
+
+ /*
+ * MIN_SHARES has to be unscaled here to support per-CPU partitioning
+ * of a group with small tg->shares value. It is a floor value which is
+ * assigned as a minimum load.weight to the sched_entity representing
+ * the group on a CPU.
+ *
+ * E.g. on 64-bit for a group with tg->shares of scale_load(15)=15*1024
+ * on an 8-core system with 8 tasks each runnable on one CPU shares has
+ * to be 15*1024*1/8=1920 instead of scale_load(MIN_SHARES)=2*1024. In
+ * case no task is runnable on a CPU MIN_SHARES=2 should be returned
+ * instead of 0.
+ */
+ return clamp_t(long, shares, MIN_SHARES, tg_shares);
+}
+
+/*
+ * This calculates the effective runnable weight for a group entity based on
+ * the group entity weight calculated above.
+ *
+ * Because of the above approximation (2), our group entity weight is
+ * an load_avg based ratio (3). This means that it includes blocked load and
+ * does not represent the runnable weight.
+ *
+ * Approximate the group entity's runnable weight per ratio from the group
+ * runqueue:
+ *
+ * grq->avg.runnable_load_avg
+ * ge->runnable_weight = ge->load.weight * -------------------------- (7)
+ * grq->avg.load_avg
+ *
+ * However, analogous to above, since the avg numbers are slow, this leads to
+ * transients in the from-idle case. Instead we use:
+ *
+ * ge->runnable_weight = ge->load.weight *
+ *
+ * max(grq->avg.runnable_load_avg, grq->runnable_weight)
+ * ----------------------------------------------------- (8)
+ * max(grq->avg.load_avg, grq->load.weight)
+ *
+ * Where these max() serve both to use the 'instant' values to fix the slow
+ * from-idle and avoid the /0 on to-idle, similar to (6).
+ */
+static long calc_group_runnable(struct cfs_rq *cfs_rq, long shares)
+{
+ long runnable, load_avg;
+
+ load_avg = max(cfs_rq->avg.load_avg,
+ scale_load_down(cfs_rq->load.weight));
+
+ runnable = max(cfs_rq->avg.runnable_load_avg,
+ scale_load_down(cfs_rq->runnable_weight));
+
+ runnable *= shares;
+ if (load_avg)
+ runnable /= load_avg;
+
+ return clamp_t(long, runnable, MIN_SHARES, shares);
+}
+#endif /* CONFIG_SMP */
+
+static inline int throttled_hierarchy(struct cfs_rq *cfs_rq);
+
+/*
+ * Recomputes the group entity based on the current state of its group
+ * runqueue.
+ */
+static void update_cfs_group(struct sched_entity *se)
+{
+ struct cfs_rq *gcfs_rq = group_cfs_rq(se);
+ long shares, runnable;
+
+ if (!gcfs_rq)
+ return;
+
+ if (throttled_hierarchy(gcfs_rq))
+ return;
+
+#ifndef CONFIG_SMP
+ runnable = shares = READ_ONCE(gcfs_rq->tg->shares);
+
+ if (likely(se->load.weight == shares))
+ return;
+#else
+ shares = calc_group_shares(gcfs_rq);
+ runnable = calc_group_runnable(gcfs_rq, shares);
+#endif
+
+ reweight_entity(cfs_rq_of(se), se, shares, runnable);
+}
+
+#else /* CONFIG_FAIR_GROUP_SCHED */
+static inline void update_cfs_group(struct sched_entity *se)
+{
+}
+#endif /* CONFIG_FAIR_GROUP_SCHED */
+
+static inline void cfs_rq_util_change(struct cfs_rq *cfs_rq, int flags)
+{
+ struct rq *rq = rq_of(cfs_rq);
+
+ if (&rq->cfs == cfs_rq || (flags & SCHED_CPUFREQ_MIGRATION)) {
+ /*
+ * There are a few boundary cases this might miss but it should
+ * get called often enough that that should (hopefully) not be
+ * a real problem.
+ *
+ * It will not get called when we go idle, because the idle
+ * thread is a different class (!fair), nor will the utilization
+ * number include things like RT tasks.
+ *
+ * As is, the util number is not freq-invariant (we'd have to
+ * implement arch_scale_freq_capacity() for that).
+ *
+ * See cpu_util().
+ */
+ cpufreq_update_util(rq, flags);
+ }
+}
+
+#ifdef CONFIG_SMP
+#ifdef CONFIG_FAIR_GROUP_SCHED
+/**
+ * update_tg_load_avg - update the tg's load avg
+ * @cfs_rq: the cfs_rq whose avg changed
+ * @force: update regardless of how small the difference
+ *
+ * This function 'ensures': tg->load_avg := \Sum tg->cfs_rq[]->avg.load.
+ * However, because tg->load_avg is a global value there are performance
+ * considerations.
+ *
+ * In order to avoid having to look at the other cfs_rq's, we use a
+ * differential update where we store the last value we propagated. This in
+ * turn allows skipping updates if the differential is 'small'.
+ *
+ * Updating tg's load_avg is necessary before update_cfs_share().
+ */
+static inline void update_tg_load_avg(struct cfs_rq *cfs_rq, int force)
+{
+ long delta = cfs_rq->avg.load_avg - cfs_rq->tg_load_avg_contrib;
+
+ /*
+ * No need to update load_avg for root_task_group as it is not used.
+ */
+ if (cfs_rq->tg == &root_task_group)
+ return;
+
+ if (force || abs(delta) > cfs_rq->tg_load_avg_contrib / 64) {
+ atomic_long_add(delta, &cfs_rq->tg->load_avg);
+ cfs_rq->tg_load_avg_contrib = cfs_rq->avg.load_avg;
+ }
+}
+
+/*
+ * Called within set_task_rq() right before setting a task's CPU. The
+ * caller only guarantees p->pi_lock is held; no other assumptions,
+ * including the state of rq->lock, should be made.
+ */
+void set_task_rq_fair(struct sched_entity *se,
+ struct cfs_rq *prev, struct cfs_rq *next)
+{
+ u64 p_last_update_time;
+ u64 n_last_update_time;
+
+ if (!sched_feat(ATTACH_AGE_LOAD))
+ return;
+
+ /*
+ * We are supposed to update the task to "current" time, then its up to
+ * date and ready to go to new CPU/cfs_rq. But we have difficulty in
+ * getting what current time is, so simply throw away the out-of-date
+ * time. This will result in the wakee task is less decayed, but giving
+ * the wakee more load sounds not bad.
+ */
+ if (!(se->avg.last_update_time && prev))
+ return;
+
+#ifndef CONFIG_64BIT
+ {
+ u64 p_last_update_time_copy;
+ u64 n_last_update_time_copy;
+
+ do {
+ p_last_update_time_copy = prev->load_last_update_time_copy;
+ n_last_update_time_copy = next->load_last_update_time_copy;
+
+ smp_rmb();
+
+ p_last_update_time = prev->avg.last_update_time;
+ n_last_update_time = next->avg.last_update_time;
+
+ } while (p_last_update_time != p_last_update_time_copy ||
+ n_last_update_time != n_last_update_time_copy);
+ }
+#else
+ p_last_update_time = prev->avg.last_update_time;
+ n_last_update_time = next->avg.last_update_time;
+#endif
+ __update_load_avg_blocked_se(p_last_update_time, se);
+ se->avg.last_update_time = n_last_update_time;
+}
+
+
+/*
+ * When on migration a sched_entity joins/leaves the PELT hierarchy, we need to
+ * propagate its contribution. The key to this propagation is the invariant
+ * that for each group:
+ *
+ * ge->avg == grq->avg (1)
+ *
+ * _IFF_ we look at the pure running and runnable sums. Because they
+ * represent the very same entity, just at different points in the hierarchy.
+ *
+ * Per the above update_tg_cfs_util() is trivial and simply copies the running
+ * sum over (but still wrong, because the group entity and group rq do not have
+ * their PELT windows aligned).
+ *
+ * However, update_tg_cfs_runnable() is more complex. So we have:
+ *
+ * ge->avg.load_avg = ge->load.weight * ge->avg.runnable_avg (2)
+ *
+ * And since, like util, the runnable part should be directly transferable,
+ * the following would _appear_ to be the straight forward approach:
+ *
+ * grq->avg.load_avg = grq->load.weight * grq->avg.runnable_avg (3)
+ *
+ * And per (1) we have:
+ *
+ * ge->avg.runnable_avg == grq->avg.runnable_avg
+ *
+ * Which gives:
+ *
+ * ge->load.weight * grq->avg.load_avg
+ * ge->avg.load_avg = ----------------------------------- (4)
+ * grq->load.weight
+ *
+ * Except that is wrong!
+ *
+ * Because while for entities historical weight is not important and we
+ * really only care about our future and therefore can consider a pure
+ * runnable sum, runqueues can NOT do this.
+ *
+ * We specifically want runqueues to have a load_avg that includes
+ * historical weights. Those represent the blocked load, the load we expect
+ * to (shortly) return to us. This only works by keeping the weights as
+ * integral part of the sum. We therefore cannot decompose as per (3).
+ *
+ * Another reason this doesn't work is that runnable isn't a 0-sum entity.
+ * Imagine a rq with 2 tasks that each are runnable 2/3 of the time. Then the
+ * rq itself is runnable anywhere between 2/3 and 1 depending on how the
+ * runnable section of these tasks overlap (or not). If they were to perfectly
+ * align the rq as a whole would be runnable 2/3 of the time. If however we
+ * always have at least 1 runnable task, the rq as a whole is always runnable.
+ *
+ * So we'll have to approximate.. :/
+ *
+ * Given the constraint:
+ *
+ * ge->avg.running_sum <= ge->avg.runnable_sum <= LOAD_AVG_MAX
+ *
+ * We can construct a rule that adds runnable to a rq by assuming minimal
+ * overlap.
+ *
+ * On removal, we'll assume each task is equally runnable; which yields:
+ *
+ * grq->avg.runnable_sum = grq->avg.load_sum / grq->load.weight
+ *
+ * XXX: only do this for the part of runnable > running ?
+ *
+ */
+
+static inline void
+update_tg_cfs_util(struct cfs_rq *cfs_rq, struct sched_entity *se, struct cfs_rq *gcfs_rq)
+{
+ long delta = gcfs_rq->avg.util_avg - se->avg.util_avg;
+
+ /* Nothing to update */
+ if (!delta)
+ return;
+
+ /*
+ * The relation between sum and avg is:
+ *
+ * LOAD_AVG_MAX - 1024 + sa->period_contrib
+ *
+ * however, the PELT windows are not aligned between grq and gse.
+ */
+
+ /* Set new sched_entity's utilization */
+ se->avg.util_avg = gcfs_rq->avg.util_avg;
+ se->avg.util_sum = se->avg.util_avg * LOAD_AVG_MAX;
+
+ /* Update parent cfs_rq utilization */
+ add_positive(&cfs_rq->avg.util_avg, delta);
+ cfs_rq->avg.util_sum = cfs_rq->avg.util_avg * LOAD_AVG_MAX;
+}
+
+static inline void
+update_tg_cfs_runnable(struct cfs_rq *cfs_rq, struct sched_entity *se, struct cfs_rq *gcfs_rq)
+{
+ long delta_avg, running_sum, runnable_sum = gcfs_rq->prop_runnable_sum;
+ unsigned long runnable_load_avg, load_avg;
+ u64 runnable_load_sum, load_sum = 0;
+ s64 delta_sum;
+
+ if (!runnable_sum)
+ return;
+
+ gcfs_rq->prop_runnable_sum = 0;
+
+ if (runnable_sum >= 0) {
+ /*
+ * Add runnable; clip at LOAD_AVG_MAX. Reflects that until
+ * the CPU is saturated running == runnable.
+ */
+ runnable_sum += se->avg.load_sum;
+ runnable_sum = min(runnable_sum, (long)LOAD_AVG_MAX);
+ } else {
+ /*
+ * Estimate the new unweighted runnable_sum of the gcfs_rq by
+ * assuming all tasks are equally runnable.
+ */
+ if (scale_load_down(gcfs_rq->load.weight)) {
+ load_sum = div_s64(gcfs_rq->avg.load_sum,
+ scale_load_down(gcfs_rq->load.weight));
+ }
+
+ /* But make sure to not inflate se's runnable */
+ runnable_sum = min(se->avg.load_sum, load_sum);
+ }
+
+ /*
+ * runnable_sum can't be lower than running_sum
+ * Rescale running sum to be in the same range as runnable sum
+ * running_sum is in [0 : LOAD_AVG_MAX << SCHED_CAPACITY_SHIFT]
+ * runnable_sum is in [0 : LOAD_AVG_MAX]
+ */
+ running_sum = se->avg.util_sum >> SCHED_CAPACITY_SHIFT;
+ runnable_sum = max(runnable_sum, running_sum);
+
+ load_sum = (s64)se_weight(se) * runnable_sum;
+ load_avg = div_s64(load_sum, LOAD_AVG_MAX);
+
+ delta_sum = load_sum - (s64)se_weight(se) * se->avg.load_sum;
+ delta_avg = load_avg - se->avg.load_avg;
+
+ se->avg.load_sum = runnable_sum;
+ se->avg.load_avg = load_avg;
+ add_positive(&cfs_rq->avg.load_avg, delta_avg);
+ add_positive(&cfs_rq->avg.load_sum, delta_sum);
+
+ runnable_load_sum = (s64)se_runnable(se) * runnable_sum;
+ runnable_load_avg = div_s64(runnable_load_sum, LOAD_AVG_MAX);
+ delta_sum = runnable_load_sum - se_weight(se) * se->avg.runnable_load_sum;
+ delta_avg = runnable_load_avg - se->avg.runnable_load_avg;
+
+ se->avg.runnable_load_sum = runnable_sum;
+ se->avg.runnable_load_avg = runnable_load_avg;
+
+ if (se->on_rq) {
+ add_positive(&cfs_rq->avg.runnable_load_avg, delta_avg);
+ add_positive(&cfs_rq->avg.runnable_load_sum, delta_sum);
+ }
+}
+
+static inline void add_tg_cfs_propagate(struct cfs_rq *cfs_rq, long runnable_sum)
+{
+ cfs_rq->propagate = 1;
+ cfs_rq->prop_runnable_sum += runnable_sum;
+}
+
+/* Update task and its cfs_rq load average */
+static inline int propagate_entity_load_avg(struct sched_entity *se)
+{
+ struct cfs_rq *cfs_rq, *gcfs_rq;
+
+ if (entity_is_task(se))
+ return 0;
+
+ gcfs_rq = group_cfs_rq(se);
+ if (!gcfs_rq->propagate)
+ return 0;
+
+ gcfs_rq->propagate = 0;
+
+ cfs_rq = cfs_rq_of(se);
+
+ add_tg_cfs_propagate(cfs_rq, gcfs_rq->prop_runnable_sum);
+
+ update_tg_cfs_util(cfs_rq, se, gcfs_rq);
+ update_tg_cfs_runnable(cfs_rq, se, gcfs_rq);
+
+ trace_pelt_cfs_tp(cfs_rq);
+ trace_pelt_se_tp(se);
+
+ return 1;
+}
+
+/*
+ * Check if we need to update the load and the utilization of a blocked
+ * group_entity:
+ */
+static inline bool skip_blocked_update(struct sched_entity *se)
+{
+ struct cfs_rq *gcfs_rq = group_cfs_rq(se);
+
+ /*
+ * If sched_entity still have not zero load or utilization, we have to
+ * decay it:
+ */
+ if (se->avg.load_avg || se->avg.util_avg)
+ return false;
+
+ /*
+ * If there is a pending propagation, we have to update the load and
+ * the utilization of the sched_entity:
+ */
+ if (gcfs_rq->propagate)
+ return false;
+
+ /*
+ * Otherwise, the load and the utilization of the sched_entity is
+ * already zero and there is no pending propagation, so it will be a
+ * waste of time to try to decay it:
+ */
+ return true;
+}
+
+#else /* CONFIG_FAIR_GROUP_SCHED */
+
+static inline void update_tg_load_avg(struct cfs_rq *cfs_rq, int force) {}
+
+static inline int propagate_entity_load_avg(struct sched_entity *se)
+{
+ return 0;
+}
+
+static inline void add_tg_cfs_propagate(struct cfs_rq *cfs_rq, long runnable_sum) {}
+
+#endif /* CONFIG_FAIR_GROUP_SCHED */
+
+/**
+ * update_cfs_rq_load_avg - update the cfs_rq's load/util averages
+ * @now: current time, as per cfs_rq_clock_pelt()
+ * @cfs_rq: cfs_rq to update
+ *
+ * The cfs_rq avg is the direct sum of all its entities (blocked and runnable)
+ * avg. The immediate corollary is that all (fair) tasks must be attached, see
+ * post_init_entity_util_avg().
+ *
+ * cfs_rq->avg is used for task_h_load() and update_cfs_share() for example.
+ *
+ * Returns true if the load decayed or we removed load.
+ *
+ * Since both these conditions indicate a changed cfs_rq->avg.load we should
+ * call update_tg_load_avg() when this function returns true.
+ */
+static inline int
+update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq)
+{
+ unsigned long removed_load = 0, removed_util = 0, removed_runnable_sum = 0;
+ struct sched_avg *sa = &cfs_rq->avg;
+ int decayed = 0;
+
+ if (cfs_rq->removed.nr) {
+ unsigned long r;
+ u32 divider = LOAD_AVG_MAX - 1024 + sa->period_contrib;
+
+ raw_spin_lock(&cfs_rq->removed.lock);
+ swap(cfs_rq->removed.util_avg, removed_util);
+ swap(cfs_rq->removed.load_avg, removed_load);
+ swap(cfs_rq->removed.runnable_sum, removed_runnable_sum);
+ cfs_rq->removed.nr = 0;
+ raw_spin_unlock(&cfs_rq->removed.lock);
+
+ r = removed_load;
+ sub_positive(&sa->load_avg, r);
+ sub_positive(&sa->load_sum, r * divider);
+
+ r = removed_util;
+ sub_positive(&sa->util_avg, r);
+ sub_positive(&sa->util_sum, r * divider);
+
+ add_tg_cfs_propagate(cfs_rq, -(long)removed_runnable_sum);
+
+ decayed = 1;
+ }
+
+ decayed |= __update_load_avg_cfs_rq(now, cfs_rq);
+
+#ifndef CONFIG_64BIT
+ smp_wmb();
+ cfs_rq->load_last_update_time_copy = sa->last_update_time;
+#endif
+
+ return decayed;
+}
+
+/**
+ * attach_entity_load_avg - attach this entity to its cfs_rq load avg
+ * @cfs_rq: cfs_rq to attach to
+ * @se: sched_entity to attach
+ * @flags: migration hints
+ *
+ * Must call update_cfs_rq_load_avg() before this, since we rely on
+ * cfs_rq->avg.last_update_time being current.
+ */
+static void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
+{
+ u32 divider = LOAD_AVG_MAX - 1024 + cfs_rq->avg.period_contrib;
+
+ /*
+ * When we attach the @se to the @cfs_rq, we must align the decay
+ * window because without that, really weird and wonderful things can
+ * happen.
+ *
+ * XXX illustrate
+ */
+ se->avg.last_update_time = cfs_rq->avg.last_update_time;
+ se->avg.period_contrib = cfs_rq->avg.period_contrib;
+
+ /*
+ * Hell(o) Nasty stuff.. we need to recompute _sum based on the new
+ * period_contrib. This isn't strictly correct, but since we're
+ * entirely outside of the PELT hierarchy, nobody cares if we truncate
+ * _sum a little.
+ */
+ se->avg.util_sum = se->avg.util_avg * divider;
+
+ se->avg.load_sum = divider;
+ if (se_weight(se)) {
+ se->avg.load_sum =
+ div_u64(se->avg.load_avg * se->avg.load_sum, se_weight(se));
+ }
+
+ se->avg.runnable_load_sum = se->avg.load_sum;
+
+ enqueue_load_avg(cfs_rq, se);
+ cfs_rq->avg.util_avg += se->avg.util_avg;
+ cfs_rq->avg.util_sum += se->avg.util_sum;
+
+ add_tg_cfs_propagate(cfs_rq, se->avg.load_sum);
+
+ cfs_rq_util_change(cfs_rq, flags);
+
+ trace_pelt_cfs_tp(cfs_rq);
+}
+
+/**
+ * detach_entity_load_avg - detach this entity from its cfs_rq load avg
+ * @cfs_rq: cfs_rq to detach from
+ * @se: sched_entity to detach
+ *
+ * Must call update_cfs_rq_load_avg() before this, since we rely on
+ * cfs_rq->avg.last_update_time being current.
+ */
+static void detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+ dequeue_load_avg(cfs_rq, se);
+ sub_positive(&cfs_rq->avg.util_avg, se->avg.util_avg);
+ sub_positive(&cfs_rq->avg.util_sum, se->avg.util_sum);
+
+ add_tg_cfs_propagate(cfs_rq, -se->avg.load_sum);
+
+ cfs_rq_util_change(cfs_rq, 0);
+
+ trace_pelt_cfs_tp(cfs_rq);
+}
+
+/*
+ * Optional action to be done while updating the load average
+ */
+#define UPDATE_TG 0x1
+#define SKIP_AGE_LOAD 0x2
+#define DO_ATTACH 0x4
+
+/* Update task and its cfs_rq load average */
+static inline void update_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
+{
+ u64 now = cfs_rq_clock_pelt(cfs_rq);
+ int decayed;
+
+ /*
+ * Track task load average for carrying it to new CPU after migrated, and
+ * track group sched_entity load average for task_h_load calc in migration
+ */
+ if (se->avg.last_update_time && !(flags & SKIP_AGE_LOAD))
+ __update_load_avg_se(now, cfs_rq, se);
+
+ decayed = update_cfs_rq_load_avg(now, cfs_rq);
+ decayed |= propagate_entity_load_avg(se);
+
+ if (!se->avg.last_update_time && (flags & DO_ATTACH)) {
+
+ /*
+ * DO_ATTACH means we're here from enqueue_entity().
+ * !last_update_time means we've passed through
+ * migrate_task_rq_fair() indicating we migrated.
+ *
+ * IOW we're enqueueing a task on a new CPU.
+ */
+ attach_entity_load_avg(cfs_rq, se, SCHED_CPUFREQ_MIGRATION);
+ update_tg_load_avg(cfs_rq, 0);
+
+ } else if (decayed) {
+ cfs_rq_util_change(cfs_rq, 0);
+
+ if (flags & UPDATE_TG)
+ update_tg_load_avg(cfs_rq, 0);
+ }
+}
+
+#ifndef CONFIG_64BIT
+static inline u64 cfs_rq_last_update_time(struct cfs_rq *cfs_rq)
+{
+ u64 last_update_time_copy;
+ u64 last_update_time;
+
+ do {
+ last_update_time_copy = cfs_rq->load_last_update_time_copy;
+ smp_rmb();
+ last_update_time = cfs_rq->avg.last_update_time;
+ } while (last_update_time != last_update_time_copy);
+
+ return last_update_time;
+}
+#else
+static inline u64 cfs_rq_last_update_time(struct cfs_rq *cfs_rq)
+{
+ return cfs_rq->avg.last_update_time;
+}
+#endif
+
+/*
+ * Synchronize entity load avg of dequeued entity without locking
+ * the previous rq.
+ */
+static void sync_entity_load_avg(struct sched_entity *se)
+{
+ struct cfs_rq *cfs_rq = cfs_rq_of(se);
+ u64 last_update_time;
+
+ last_update_time = cfs_rq_last_update_time(cfs_rq);
+ __update_load_avg_blocked_se(last_update_time, se);
+}
+
+/*
+ * Task first catches up with cfs_rq, and then subtract
+ * itself from the cfs_rq (task must be off the queue now).
+ */
+static void remove_entity_load_avg(struct sched_entity *se)
+{
+ struct cfs_rq *cfs_rq = cfs_rq_of(se);
+ unsigned long flags;
+
+ /*
+ * tasks cannot exit without having gone through wake_up_new_task() ->
+ * post_init_entity_util_avg() which will have added things to the
+ * cfs_rq, so we can remove unconditionally.
+ */
+
+ sync_entity_load_avg(se);
+
+ raw_spin_lock_irqsave(&cfs_rq->removed.lock, flags);
+ ++cfs_rq->removed.nr;
+ cfs_rq->removed.util_avg += se->avg.util_avg;
+ cfs_rq->removed.load_avg += se->avg.load_avg;
+ cfs_rq->removed.runnable_sum += se->avg.load_sum; /* == runnable_sum */
+ raw_spin_unlock_irqrestore(&cfs_rq->removed.lock, flags);
+}
+
+static inline unsigned long cfs_rq_runnable_load_avg(struct cfs_rq *cfs_rq)
+{
+ return cfs_rq->avg.runnable_load_avg;
+}
+
+static inline unsigned long cfs_rq_load_avg(struct cfs_rq *cfs_rq)
+{
+ return cfs_rq->avg.load_avg;
+}
+
+static inline unsigned long task_util(struct task_struct *p)
+{
+ return READ_ONCE(p->se.avg.util_avg);
+}
+
+static inline unsigned long _task_util_est(struct task_struct *p)
+{
+ struct util_est ue = READ_ONCE(p->se.avg.util_est);
+
+ return (max(ue.ewma, ue.enqueued) | UTIL_AVG_UNCHANGED);
+}
+
+static inline unsigned long task_util_est(struct task_struct *p)
+{
+ return max(task_util(p), _task_util_est(p));
+}
+
+#ifdef CONFIG_UCLAMP_TASK
+static inline unsigned long uclamp_task_util(struct task_struct *p)
+{
+ return clamp(task_util_est(p),
+ uclamp_eff_value(p, UCLAMP_MIN),
+ uclamp_eff_value(p, UCLAMP_MAX));
+}
+#else
+static inline unsigned long uclamp_task_util(struct task_struct *p)
+{
+ return task_util_est(p);
+}
+#endif
+
+static inline void util_est_enqueue(struct cfs_rq *cfs_rq,
+ struct task_struct *p)
+{
+ unsigned int enqueued;
+
+ if (!sched_feat(UTIL_EST))
+ return;
+
+ /* Update root cfs_rq's estimated utilization */
+ enqueued = cfs_rq->avg.util_est.enqueued;
+ enqueued += _task_util_est(p);
+ WRITE_ONCE(cfs_rq->avg.util_est.enqueued, enqueued);
+}
+
+/*
+ * Check if a (signed) value is within a specified (unsigned) margin,
+ * based on the observation that:
+ *
+ * abs(x) < y := (unsigned)(x + y - 1) < (2 * y - 1)
+ *
+ * NOTE: this only works when value + maring < INT_MAX.
+ */
+static inline bool within_margin(int value, int margin)
+{
+ return ((unsigned int)(value + margin - 1) < (2 * margin - 1));
+}
+
+static void
+util_est_dequeue(struct cfs_rq *cfs_rq, struct task_struct *p, bool task_sleep)
+{
+ long last_ewma_diff;
+ struct util_est ue;
+ int cpu;
+
+ if (!sched_feat(UTIL_EST))
+ return;
+
+ /* Update root cfs_rq's estimated utilization */
+ ue.enqueued = cfs_rq->avg.util_est.enqueued;
+ ue.enqueued -= min_t(unsigned int, ue.enqueued, _task_util_est(p));
+ WRITE_ONCE(cfs_rq->avg.util_est.enqueued, ue.enqueued);
+
+ /*
+ * Skip update of task's estimated utilization when the task has not
+ * yet completed an activation, e.g. being migrated.
+ */
+ if (!task_sleep)
+ return;
+
+ /*
+ * If the PELT values haven't changed since enqueue time,
+ * skip the util_est update.
+ */
+ ue = p->se.avg.util_est;
+ if (ue.enqueued & UTIL_AVG_UNCHANGED)
+ return;
+
+ /*
+ * Reset EWMA on utilization increases, the moving average is used only
+ * to smooth utilization decreases.
+ */
+ ue.enqueued = (task_util(p) | UTIL_AVG_UNCHANGED);
+ if (sched_feat(UTIL_EST_FASTUP)) {
+ if (ue.ewma < ue.enqueued) {
+ ue.ewma = ue.enqueued;
+ goto done;
+ }
+ }
+
+ /*
+ * Skip update of task's estimated utilization when its EWMA is
+ * already ~1% close to its last activation value.
+ */
+ last_ewma_diff = ue.enqueued - ue.ewma;
+ if (within_margin(last_ewma_diff, (SCHED_CAPACITY_SCALE / 100)))
+ return;
+
+ /*
+ * To avoid overestimation of actual task utilization, skip updates if
+ * we cannot grant there is idle time in this CPU.
+ */
+ cpu = cpu_of(rq_of(cfs_rq));
+ if (task_util(p) > capacity_orig_of(cpu))
+ return;
+
+ /*
+ * Update Task's estimated utilization
+ *
+ * When *p completes an activation we can consolidate another sample
+ * of the task size. This is done by storing the current PELT value
+ * as ue.enqueued and by using this value to update the Exponential
+ * Weighted Moving Average (EWMA):
+ *
+ * ewma(t) = w * task_util(p) + (1-w) * ewma(t-1)
+ * = w * task_util(p) + ewma(t-1) - w * ewma(t-1)
+ * = w * (task_util(p) - ewma(t-1)) + ewma(t-1)
+ * = w * ( last_ewma_diff ) + ewma(t-1)
+ * = w * (last_ewma_diff + ewma(t-1) / w)
+ *
+ * Where 'w' is the weight of new samples, which is configured to be
+ * 0.25, thus making w=1/4 ( >>= UTIL_EST_WEIGHT_SHIFT)
+ */
+ ue.ewma <<= UTIL_EST_WEIGHT_SHIFT;
+ ue.ewma += last_ewma_diff;
+ ue.ewma >>= UTIL_EST_WEIGHT_SHIFT;
+done:
+ WRITE_ONCE(p->se.avg.util_est, ue);
+}
+
+static inline int task_fits_capacity(struct task_struct *p, long capacity)
+{
+ return fits_capacity(uclamp_task_util(p), capacity);
+}
+
+static inline void update_misfit_status(struct task_struct *p, struct rq *rq)
+{
+ if (!static_branch_unlikely(&sched_asym_cpucapacity))
+ return;
+
+ if (!p || p->nr_cpus_allowed == 1) {
+ rq->misfit_task_load = 0;
+ return;
+ }
+
+ if (task_fits_capacity(p, capacity_of(cpu_of(rq)))) {
+ rq->misfit_task_load = 0;
+ return;
+ }
+
+ /*
+ * Make sure that misfit_task_load will not be null even if
+ * task_h_load() returns 0.
+ */
+ rq->misfit_task_load = max_t(unsigned long, task_h_load(p), 1);
+}
+
+#else /* CONFIG_SMP */
+
+#define UPDATE_TG 0x0
+#define SKIP_AGE_LOAD 0x0
+#define DO_ATTACH 0x0
+
+static inline void update_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se, int not_used1)
+{
+ cfs_rq_util_change(cfs_rq, 0);
+}
+
+static inline void remove_entity_load_avg(struct sched_entity *se) {}
+
+static inline void
+attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) {}
+static inline void
+detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) {}
+
+static inline int idle_balance(struct rq *rq, struct rq_flags *rf)
+{
+ return 0;
+}
+
+static inline void
+util_est_enqueue(struct cfs_rq *cfs_rq, struct task_struct *p) {}
+
+static inline void
+util_est_dequeue(struct cfs_rq *cfs_rq, struct task_struct *p,
+ bool task_sleep) {}
+static inline void update_misfit_status(struct task_struct *p, struct rq *rq) {}
+
+#endif /* CONFIG_SMP */
+
+static void check_spread(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+#ifdef CONFIG_SCHED_DEBUG
+ s64 d = se->vruntime - cfs_rq->min_vruntime;
+
+ if (d < 0)
+ d = -d;
+
+ if (d > 3*sysctl_sched_latency)
+ schedstat_inc(cfs_rq->nr_spread_over);
+#endif
+}
+
+static inline bool entity_is_long_sleeper(struct sched_entity *se)
+{
+ struct cfs_rq *cfs_rq;
+ u64 sleep_time;
+
+ if (se->exec_start == 0)
+ return false;
+
+ cfs_rq = cfs_rq_of(se);
+
+ sleep_time = rq_clock_task(rq_of(cfs_rq));
+
+ /* Happen while migrating because of clock task divergence */
+ if (sleep_time <= se->exec_start)
+ return false;
+
+ sleep_time -= se->exec_start;
+ if (sleep_time > ((1ULL << 63) / scale_load_down(NICE_0_LOAD)))
+ return true;
+
+ return false;
+}
+
+static void
+place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial)
+{
+ u64 vruntime = cfs_rq->min_vruntime;
+
+ /*
+ * The 'current' period is already promised to the current tasks,
+ * however the extra weight of the new task will slow them down a
+ * little, place the new task so that it fits in the slot that
+ * stays open at the end.
+ */
+ if (initial && sched_feat(START_DEBIT))
+ vruntime += sched_vslice(cfs_rq, se);
+
+ /* sleeps up to a single latency don't count. */
+ if (!initial) {
+ unsigned long thresh = sysctl_sched_latency;
+
+ /*
+ * Halve their sleep time's effect, to allow
+ * for a gentler effect of sleepers:
+ */
+ if (sched_feat(GENTLE_FAIR_SLEEPERS))
+ thresh >>= 1;
+
+ vruntime -= thresh;
+ }
+
+ /*
+ * Pull vruntime of the entity being placed to the base level of
+ * cfs_rq, to prevent boosting it if placed backwards.
+ * However, min_vruntime can advance much faster than real time, with
+ * the extreme being when an entity with the minimal weight always runs
+ * on the cfs_rq. If the waking entity slept for a long time, its
+ * vruntime difference from min_vruntime may overflow s64 and their
+ * comparison may get inversed, so ignore the entity's original
+ * vruntime in that case.
+ * The maximal vruntime speedup is given by the ratio of normal to
+ * minimal weight: scale_load_down(NICE_0_LOAD) / MIN_SHARES.
+ * When placing a migrated waking entity, its exec_start has been set
+ * from a different rq. In order to take into account a possible
+ * divergence between new and prev rq's clocks task because of irq and
+ * stolen time, we take an additional margin.
+ * So, cutting off on the sleep time of
+ * 2^63 / scale_load_down(NICE_0_LOAD) ~ 104 days
+ * should be safe.
+ */
+ if (entity_is_long_sleeper(se))
+ se->vruntime = vruntime;
+ else
+ se->vruntime = max_vruntime(se->vruntime, vruntime);
+}
+
+static void check_enqueue_throttle(struct cfs_rq *cfs_rq);
+
+static inline void check_schedstat_required(void)
+{
+#ifdef CONFIG_SCHEDSTATS
+ if (schedstat_enabled())
+ return;
+
+ /* Force schedstat enabled if a dependent tracepoint is active */
+ if (trace_sched_stat_wait_enabled() ||
+ trace_sched_stat_sleep_enabled() ||
+ trace_sched_stat_iowait_enabled() ||
+ trace_sched_stat_blocked_enabled() ||
+ trace_sched_stat_runtime_enabled()) {
+ printk_deferred_once("Scheduler tracepoints stat_sleep, stat_iowait, "
+ "stat_blocked and stat_runtime require the "
+ "kernel parameter schedstats=enable or "
+ "kernel.sched_schedstats=1\n");
+ }
+#endif
+}
+
+static inline bool cfs_bandwidth_used(void);
+
+/*
+ * MIGRATION
+ *
+ * dequeue
+ * update_curr()
+ * update_min_vruntime()
+ * vruntime -= min_vruntime
+ *
+ * enqueue
+ * update_curr()
+ * update_min_vruntime()
+ * vruntime += min_vruntime
+ *
+ * this way the vruntime transition between RQs is done when both
+ * min_vruntime are up-to-date.
+ *
+ * WAKEUP (remote)
+ *
+ * ->migrate_task_rq_fair() (p->state == TASK_WAKING)
+ * vruntime -= min_vruntime
+ *
+ * enqueue
+ * update_curr()
+ * update_min_vruntime()
+ * vruntime += min_vruntime
+ *
+ * this way we don't have the most up-to-date min_vruntime on the originating
+ * CPU and an up-to-date min_vruntime on the destination CPU.
+ */
+
+static void
+enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
+{
+ bool renorm = !(flags & ENQUEUE_WAKEUP) || (flags & ENQUEUE_MIGRATED);
+ bool curr = cfs_rq->curr == se;
+
+ /*
+ * If we're the current task, we must renormalise before calling
+ * update_curr().
+ */
+ if (renorm && curr)
+ se->vruntime += cfs_rq->min_vruntime;
+
+ update_curr(cfs_rq);
+
+ /*
+ * Otherwise, renormalise after, such that we're placed at the current
+ * moment in time, instead of some random moment in the past. Being
+ * placed in the past could significantly boost this task to the
+ * fairness detriment of existing tasks.
+ */
+ if (renorm && !curr)
+ se->vruntime += cfs_rq->min_vruntime;
+
+ /*
+ * When enqueuing a sched_entity, we must:
+ * - Update loads to have both entity and cfs_rq synced with now.
+ * - Add its load to cfs_rq->runnable_avg
+ * - For group_entity, update its weight to reflect the new share of
+ * its group cfs_rq
+ * - Add its new weight to cfs_rq->load.weight
+ */
+ update_load_avg(cfs_rq, se, UPDATE_TG | DO_ATTACH);
+ update_cfs_group(se);
+ enqueue_runnable_load_avg(cfs_rq, se);
+ account_entity_enqueue(cfs_rq, se);
+
+ if (flags & ENQUEUE_WAKEUP)
+ place_entity(cfs_rq, se, 0);
+ /* Entity has migrated, no longer consider this task hot */
+ if (flags & ENQUEUE_MIGRATED)
+ se->exec_start = 0;
+
+ check_schedstat_required();
+ update_stats_enqueue(cfs_rq, se, flags);
+ check_spread(cfs_rq, se);
+ if (!curr)
+ __enqueue_entity(cfs_rq, se);
+ se->on_rq = 1;
+
+ /*
+ * When bandwidth control is enabled, cfs might have been removed
+ * because of a parent been throttled but cfs->nr_running > 1. Try to
+ * add it unconditionnally.
+ */
+ if (cfs_rq->nr_running == 1 || cfs_bandwidth_used())
+ list_add_leaf_cfs_rq(cfs_rq);
+
+ if (cfs_rq->nr_running == 1)
+ check_enqueue_throttle(cfs_rq);
+}
+
+static void __clear_buddies_last(struct sched_entity *se)
+{
+ for_each_sched_entity(se) {
+ struct cfs_rq *cfs_rq = cfs_rq_of(se);
+ if (cfs_rq->last != se)
+ break;
+
+ cfs_rq->last = NULL;
+ }
+}
+
+static void __clear_buddies_next(struct sched_entity *se)
+{
+ for_each_sched_entity(se) {
+ struct cfs_rq *cfs_rq = cfs_rq_of(se);
+ if (cfs_rq->next != se)
+ break;
+
+ cfs_rq->next = NULL;
+ }
+}
+
+static void __clear_buddies_skip(struct sched_entity *se)
+{
+ for_each_sched_entity(se) {
+ struct cfs_rq *cfs_rq = cfs_rq_of(se);
+ if (cfs_rq->skip != se)
+ break;
+
+ cfs_rq->skip = NULL;
+ }
+}
+
+static void clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+ if (cfs_rq->last == se)
+ __clear_buddies_last(se);
+
+ if (cfs_rq->next == se)
+ __clear_buddies_next(se);
+
+ if (cfs_rq->skip == se)
+ __clear_buddies_skip(se);
+}
+
+static __always_inline void return_cfs_rq_runtime(struct cfs_rq *cfs_rq);
+
+static void
+dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
+{
+ /*
+ * Update run-time statistics of the 'current'.
+ */
+ update_curr(cfs_rq);
+
+ /*
+ * When dequeuing a sched_entity, we must:
+ * - Update loads to have both entity and cfs_rq synced with now.
+ * - Subtract its load from the cfs_rq->runnable_avg.
+ * - Subtract its previous weight from cfs_rq->load.weight.
+ * - For group entity, update its weight to reflect the new share
+ * of its group cfs_rq.
+ */
+ update_load_avg(cfs_rq, se, UPDATE_TG);
+ dequeue_runnable_load_avg(cfs_rq, se);
+
+ update_stats_dequeue(cfs_rq, se, flags);
+
+ clear_buddies(cfs_rq, se);
+
+ if (se != cfs_rq->curr)
+ __dequeue_entity(cfs_rq, se);
+ se->on_rq = 0;
+ account_entity_dequeue(cfs_rq, se);
+
+ /*
+ * Normalize after update_curr(); which will also have moved
+ * min_vruntime if @se is the one holding it back. But before doing
+ * update_min_vruntime() again, which will discount @se's position and
+ * can move min_vruntime forward still more.
+ */
+ if (!(flags & DEQUEUE_SLEEP))
+ se->vruntime -= cfs_rq->min_vruntime;
+
+ /* return excess runtime on last dequeue */
+ return_cfs_rq_runtime(cfs_rq);
+
+ update_cfs_group(se);
+
+ /*
+ * Now advance min_vruntime if @se was the entity holding it back,
+ * except when: DEQUEUE_SAVE && !DEQUEUE_MOVE, in this case we'll be
+ * put back on, and if we advance min_vruntime, we'll be placed back
+ * further than we started -- ie. we'll be penalized.
+ */
+ if ((flags & (DEQUEUE_SAVE | DEQUEUE_MOVE)) != DEQUEUE_SAVE)
+ update_min_vruntime(cfs_rq);
+}
+
+/*
+ * Preempt the current task with a newly woken task if needed:
+ */
+static void
+check_preempt_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr)
+{
+ unsigned long ideal_runtime, delta_exec;
+ struct sched_entity *se;
+ s64 delta;
+
+ ideal_runtime = sched_slice(cfs_rq, curr);
+ delta_exec = curr->sum_exec_runtime - curr->prev_sum_exec_runtime;
+ if (delta_exec > ideal_runtime) {
+ resched_curr(rq_of(cfs_rq));
+ /*
+ * The current task ran long enough, ensure it doesn't get
+ * re-elected due to buddy favours.
+ */
+ clear_buddies(cfs_rq, curr);
+ return;
+ }
+
+ /*
+ * Ensure that a task that missed wakeup preemption by a
+ * narrow margin doesn't have to wait for a full slice.
+ * This also mitigates buddy induced latencies under load.
+ */
+ if (delta_exec < sysctl_sched_min_granularity)
+ return;
+
+ se = __pick_first_entity(cfs_rq);
+ delta = curr->vruntime - se->vruntime;
+
+ if (delta < 0)
+ return;
+
+ if (delta > ideal_runtime)
+ resched_curr(rq_of(cfs_rq));
+}
+
+static void
+set_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+ /* 'current' is not kept within the tree. */
+ if (se->on_rq) {
+ /*
+ * Any task has to be enqueued before it get to execute on
+ * a CPU. So account for the time it spent waiting on the
+ * runqueue.
+ */
+ update_stats_wait_end(cfs_rq, se);
+ __dequeue_entity(cfs_rq, se);
+ update_load_avg(cfs_rq, se, UPDATE_TG);
+ }
+
+ update_stats_curr_start(cfs_rq, se);
+ cfs_rq->curr = se;
+
+ /*
+ * Track our maximum slice length, if the CPU's load is at
+ * least twice that of our own weight (i.e. dont track it
+ * when there are only lesser-weight tasks around):
+ */
+ if (schedstat_enabled() &&
+ rq_of(cfs_rq)->cfs.load.weight >= 2*se->load.weight) {
+ schedstat_set(se->statistics.slice_max,
+ max((u64)schedstat_val(se->statistics.slice_max),
+ se->sum_exec_runtime - se->prev_sum_exec_runtime));
+ }
+
+ se->prev_sum_exec_runtime = se->sum_exec_runtime;
+}
+
+static int
+wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se);
+
+/*
+ * Pick the next process, keeping these things in mind, in this order:
+ * 1) keep things fair between processes/task groups
+ * 2) pick the "next" process, since someone really wants that to run
+ * 3) pick the "last" process, for cache locality
+ * 4) do not run the "skip" process, if something else is available
+ */
+static struct sched_entity *
+pick_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *curr)
+{
+ struct sched_entity *left = __pick_first_entity(cfs_rq);
+ struct sched_entity *se;
+
+ /*
+ * If curr is set we have to see if its left of the leftmost entity
+ * still in the tree, provided there was anything in the tree at all.
+ */
+ if (!left || (curr && entity_before(curr, left)))
+ left = curr;
+
+ se = left; /* ideally we run the leftmost entity */
+
+ /*
+ * Avoid running the skip buddy, if running something else can
+ * be done without getting too unfair.
+ */
+ if (cfs_rq->skip == se) {
+ struct sched_entity *second;
+
+ if (se == curr) {
+ second = __pick_first_entity(cfs_rq);
+ } else {
+ second = __pick_next_entity(se);
+ if (!second || (curr && entity_before(curr, second)))
+ second = curr;
+ }
+
+ if (second && wakeup_preempt_entity(second, left) < 1)
+ se = second;
+ }
+
+ /*
+ * Prefer last buddy, try to return the CPU to a preempted task.
+ */
+ if (cfs_rq->last && wakeup_preempt_entity(cfs_rq->last, left) < 1)
+ se = cfs_rq->last;
+
+ /*
+ * Someone really wants this to run. If it's not unfair, run it.
+ */
+ if (cfs_rq->next && wakeup_preempt_entity(cfs_rq->next, left) < 1)
+ se = cfs_rq->next;
+
+ clear_buddies(cfs_rq, se);
+
+ return se;
+}
+
+static bool check_cfs_rq_runtime(struct cfs_rq *cfs_rq);
+
+static void put_prev_entity(struct cfs_rq *cfs_rq, struct sched_entity *prev)
+{
+ /*
+ * If still on the runqueue then deactivate_task()
+ * was not called and update_curr() has to be done:
+ */
+ if (prev->on_rq)
+ update_curr(cfs_rq);
+
+ /* throttle cfs_rqs exceeding runtime */
+ check_cfs_rq_runtime(cfs_rq);
+
+ check_spread(cfs_rq, prev);
+
+ if (prev->on_rq) {
+ update_stats_wait_start(cfs_rq, prev);
+ /* Put 'current' back into the tree. */
+ __enqueue_entity(cfs_rq, prev);
+ /* in !on_rq case, update occurred at dequeue */
+ update_load_avg(cfs_rq, prev, 0);
+ }
+ cfs_rq->curr = NULL;
+}
+
+static void
+entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr, int queued)
+{
+ /*
+ * Update run-time statistics of the 'current'.
+ */
+ update_curr(cfs_rq);
+
+ /*
+ * Ensure that runnable average is periodically updated.
+ */
+ update_load_avg(cfs_rq, curr, UPDATE_TG);
+ update_cfs_group(curr);
+
+#ifdef CONFIG_SCHED_HRTICK
+ /*
+ * queued ticks are scheduled to match the slice, so don't bother
+ * validating it and just reschedule.
+ */
+ if (queued) {
+ resched_curr(rq_of(cfs_rq));
+ return;
+ }
+ /*
+ * don't let the period tick interfere with the hrtick preemption
+ */
+ if (!sched_feat(DOUBLE_TICK) &&
+ hrtimer_active(&rq_of(cfs_rq)->hrtick_timer))
+ return;
+#endif
+
+ if (cfs_rq->nr_running > 1)
+ check_preempt_tick(cfs_rq, curr);
+}
+
+
+/**************************************************
+ * CFS bandwidth control machinery
+ */
+
+#ifdef CONFIG_CFS_BANDWIDTH
+
+#ifdef CONFIG_JUMP_LABEL
+static struct static_key __cfs_bandwidth_used;
+
+static inline bool cfs_bandwidth_used(void)
+{
+ return static_key_false(&__cfs_bandwidth_used);
+}
+
+void cfs_bandwidth_usage_inc(void)
+{
+ static_key_slow_inc_cpuslocked(&__cfs_bandwidth_used);
+}
+
+void cfs_bandwidth_usage_dec(void)
+{
+ static_key_slow_dec_cpuslocked(&__cfs_bandwidth_used);
+}
+#else /* CONFIG_JUMP_LABEL */
+static bool cfs_bandwidth_used(void)
+{
+ return true;
+}
+
+void cfs_bandwidth_usage_inc(void) {}
+void cfs_bandwidth_usage_dec(void) {}
+#endif /* CONFIG_JUMP_LABEL */
+
+/*
+ * default period for cfs group bandwidth.
+ * default: 0.1s, units: nanoseconds
+ */
+static inline u64 default_cfs_period(void)
+{
+ return 100000000ULL;
+}
+
+static inline u64 sched_cfs_bandwidth_slice(void)
+{
+ return (u64)sysctl_sched_cfs_bandwidth_slice * NSEC_PER_USEC;
+}
+
+/*
+ * Replenish runtime according to assigned quota. We use sched_clock_cpu
+ * directly instead of rq->clock to avoid adding additional synchronization
+ * around rq->lock.
+ *
+ * requires cfs_b->lock
+ */
+void __refill_cfs_bandwidth_runtime(struct cfs_bandwidth *cfs_b)
+{
+ if (cfs_b->quota != RUNTIME_INF)
+ cfs_b->runtime = cfs_b->quota;
+}
+
+static inline struct cfs_bandwidth *tg_cfs_bandwidth(struct task_group *tg)
+{
+ return &tg->cfs_bandwidth;
+}
+
+/* returns 0 on failure to allocate runtime */
+static int __assign_cfs_rq_runtime(struct cfs_bandwidth *cfs_b,
+ struct cfs_rq *cfs_rq, u64 target_runtime)
+{
+ u64 min_amount, amount = 0;
+
+ lockdep_assert_held(&cfs_b->lock);
+
+ /* note: this is a positive sum as runtime_remaining <= 0 */
+ min_amount = target_runtime - cfs_rq->runtime_remaining;
+
+ if (cfs_b->quota == RUNTIME_INF)
+ amount = min_amount;
+ else {
+ start_cfs_bandwidth(cfs_b);
+
+ if (cfs_b->runtime > 0) {
+ amount = min(cfs_b->runtime, min_amount);
+ cfs_b->runtime -= amount;
+ cfs_b->idle = 0;
+ }
+ }
+
+ cfs_rq->runtime_remaining += amount;
+
+ return cfs_rq->runtime_remaining > 0;
+}
+
+/* returns 0 on failure to allocate runtime */
+static int assign_cfs_rq_runtime(struct cfs_rq *cfs_rq)
+{
+ struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg);
+ int ret;
+
+ raw_spin_lock(&cfs_b->lock);
+ ret = __assign_cfs_rq_runtime(cfs_b, cfs_rq, sched_cfs_bandwidth_slice());
+ raw_spin_unlock(&cfs_b->lock);
+
+ return ret;
+}
+
+static void __account_cfs_rq_runtime(struct cfs_rq *cfs_rq, u64 delta_exec)
+{
+ /* dock delta_exec before expiring quota (as it could span periods) */
+ cfs_rq->runtime_remaining -= delta_exec;
+
+ if (likely(cfs_rq->runtime_remaining > 0))
+ return;
+
+ if (cfs_rq->throttled)
+ return;
+ /*
+ * if we're unable to extend our runtime we resched so that the active
+ * hierarchy can be throttled
+ */
+ if (!assign_cfs_rq_runtime(cfs_rq) && likely(cfs_rq->curr))
+ resched_curr(rq_of(cfs_rq));
+}
+
+static __always_inline
+void account_cfs_rq_runtime(struct cfs_rq *cfs_rq, u64 delta_exec)
+{
+ if (!cfs_bandwidth_used() || !cfs_rq->runtime_enabled)
+ return;
+
+ __account_cfs_rq_runtime(cfs_rq, delta_exec);
+}
+
+static inline int cfs_rq_throttled(struct cfs_rq *cfs_rq)
+{
+ return cfs_bandwidth_used() && cfs_rq->throttled;
+}
+
+/* check whether cfs_rq, or any parent, is throttled */
+static inline int throttled_hierarchy(struct cfs_rq *cfs_rq)
+{
+ return cfs_bandwidth_used() && cfs_rq->throttle_count;
+}
+
+/*
+ * Ensure that neither of the group entities corresponding to src_cpu or
+ * dest_cpu are members of a throttled hierarchy when performing group
+ * load-balance operations.
+ */
+static inline int throttled_lb_pair(struct task_group *tg,
+ int src_cpu, int dest_cpu)
+{
+ struct cfs_rq *src_cfs_rq, *dest_cfs_rq;
+
+ src_cfs_rq = tg->cfs_rq[src_cpu];
+ dest_cfs_rq = tg->cfs_rq[dest_cpu];
+
+ return throttled_hierarchy(src_cfs_rq) ||
+ throttled_hierarchy(dest_cfs_rq);
+}
+
+static int tg_unthrottle_up(struct task_group *tg, void *data)
+{
+ struct rq *rq = data;
+ struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)];
+
+ cfs_rq->throttle_count--;
+ if (!cfs_rq->throttle_count) {
+ cfs_rq->throttled_clock_pelt_time += rq_clock_pelt(rq) -
+ cfs_rq->throttled_clock_pelt;
+
+ /* Add cfs_rq with already running entity in the list */
+ if (cfs_rq->nr_running >= 1)
+ list_add_leaf_cfs_rq(cfs_rq);
+ }
+
+ return 0;
+}
+
+static int tg_throttle_down(struct task_group *tg, void *data)
+{
+ struct rq *rq = data;
+ struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)];
+
+ /* group is entering throttled state, stop time */
+ if (!cfs_rq->throttle_count) {
+ cfs_rq->throttled_clock_pelt = rq_clock_pelt(rq);
+ list_del_leaf_cfs_rq(cfs_rq);
+ }
+ cfs_rq->throttle_count++;
+
+ return 0;
+}
+
+static bool throttle_cfs_rq(struct cfs_rq *cfs_rq)
+{
+ struct rq *rq = rq_of(cfs_rq);
+ struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg);
+ struct sched_entity *se;
+ long task_delta, idle_task_delta, dequeue = 1;
+
+ raw_spin_lock(&cfs_b->lock);
+ /* This will start the period timer if necessary */
+ if (__assign_cfs_rq_runtime(cfs_b, cfs_rq, 1)) {
+ /*
+ * We have raced with bandwidth becoming available, and if we
+ * actually throttled the timer might not unthrottle us for an
+ * entire period. We additionally needed to make sure that any
+ * subsequent check_cfs_rq_runtime calls agree not to throttle
+ * us, as we may commit to do cfs put_prev+pick_next, so we ask
+ * for 1ns of runtime rather than just check cfs_b.
+ */
+ dequeue = 0;
+ } else {
+ list_add_tail_rcu(&cfs_rq->throttled_list,
+ &cfs_b->throttled_cfs_rq);
+ }
+ raw_spin_unlock(&cfs_b->lock);
+
+ if (!dequeue)
+ return false; /* Throttle no longer required. */
+
+ se = cfs_rq->tg->se[cpu_of(rq_of(cfs_rq))];
+
+ /* freeze hierarchy runnable averages while throttled */
+ rcu_read_lock();
+ walk_tg_tree_from(cfs_rq->tg, tg_throttle_down, tg_nop, (void *)rq);
+ rcu_read_unlock();
+
+ task_delta = cfs_rq->h_nr_running;
+ idle_task_delta = cfs_rq->idle_h_nr_running;
+ for_each_sched_entity(se) {
+ struct cfs_rq *qcfs_rq = cfs_rq_of(se);
+ /* throttled entity or throttle-on-deactivate */
+ if (!se->on_rq)
+ break;
+
+ if (dequeue)
+ dequeue_entity(qcfs_rq, se, DEQUEUE_SLEEP);
+ qcfs_rq->h_nr_running -= task_delta;
+ qcfs_rq->idle_h_nr_running -= idle_task_delta;
+
+ if (qcfs_rq->load.weight)
+ dequeue = 0;
+ }
+
+ if (!se)
+ sub_nr_running(rq, task_delta);
+
+ /*
+ * Note: distribution will already see us throttled via the
+ * throttled-list. rq->lock protects completion.
+ */
+ cfs_rq->throttled = 1;
+ cfs_rq->throttled_clock = rq_clock(rq);
+ return true;
+}
+
+void unthrottle_cfs_rq(struct cfs_rq *cfs_rq)
+{
+ struct rq *rq = rq_of(cfs_rq);
+ struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg);
+ struct sched_entity *se;
+ long task_delta, idle_task_delta;
+
+ se = cfs_rq->tg->se[cpu_of(rq)];
+
+ cfs_rq->throttled = 0;
+
+ update_rq_clock(rq);
+
+ raw_spin_lock(&cfs_b->lock);
+ cfs_b->throttled_time += rq_clock(rq) - cfs_rq->throttled_clock;
+ list_del_rcu(&cfs_rq->throttled_list);
+ raw_spin_unlock(&cfs_b->lock);
+
+ /* update hierarchical throttle state */
+ walk_tg_tree_from(cfs_rq->tg, tg_nop, tg_unthrottle_up, (void *)rq);
+
+ if (!cfs_rq->load.weight)
+ return;
+
+ task_delta = cfs_rq->h_nr_running;
+ idle_task_delta = cfs_rq->idle_h_nr_running;
+ for_each_sched_entity(se) {
+ if (se->on_rq)
+ break;
+ cfs_rq = cfs_rq_of(se);
+ enqueue_entity(cfs_rq, se, ENQUEUE_WAKEUP);
+
+ cfs_rq->h_nr_running += task_delta;
+ cfs_rq->idle_h_nr_running += idle_task_delta;
+
+ /* end evaluation on encountering a throttled cfs_rq */
+ if (cfs_rq_throttled(cfs_rq))
+ goto unthrottle_throttle;
+ }
+
+ for_each_sched_entity(se) {
+ cfs_rq = cfs_rq_of(se);
+
+ cfs_rq->h_nr_running += task_delta;
+ cfs_rq->idle_h_nr_running += idle_task_delta;
+
+
+ /* end evaluation on encountering a throttled cfs_rq */
+ if (cfs_rq_throttled(cfs_rq))
+ goto unthrottle_throttle;
+
+ /*
+ * One parent has been throttled and cfs_rq removed from the
+ * list. Add it back to not break the leaf list.
+ */
+ if (throttled_hierarchy(cfs_rq))
+ list_add_leaf_cfs_rq(cfs_rq);
+ }
+
+ /* At this point se is NULL and we are at root level*/
+ add_nr_running(rq, task_delta);
+
+unthrottle_throttle:
+ /*
+ * The cfs_rq_throttled() breaks in the above iteration can result in
+ * incomplete leaf list maintenance, resulting in triggering the
+ * assertion below.
+ */
+ for_each_sched_entity(se) {
+ cfs_rq = cfs_rq_of(se);
+
+ if (list_add_leaf_cfs_rq(cfs_rq))
+ break;
+ }
+
+ assert_list_leaf_cfs_rq(rq);
+
+ /* Determine whether we need to wake up potentially idle CPU: */
+ if (rq->curr == rq->idle && rq->cfs.nr_running)
+ resched_curr(rq);
+}
+
+static u64 distribute_cfs_runtime(struct cfs_bandwidth *cfs_b, u64 remaining)
+{
+ struct cfs_rq *cfs_rq;
+ u64 runtime;
+ u64 starting_runtime = remaining;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(cfs_rq, &cfs_b->throttled_cfs_rq,
+ throttled_list) {
+ struct rq *rq = rq_of(cfs_rq);
+ struct rq_flags rf;
+
+ rq_lock_irqsave(rq, &rf);
+ if (!cfs_rq_throttled(cfs_rq))
+ goto next;
+
+ /* By the above check, this should never be true */
+ SCHED_WARN_ON(cfs_rq->runtime_remaining > 0);
+
+ runtime = -cfs_rq->runtime_remaining + 1;
+ if (runtime > remaining)
+ runtime = remaining;
+ remaining -= runtime;
+
+ cfs_rq->runtime_remaining += runtime;
+
+ /* we check whether we're throttled above */
+ if (cfs_rq->runtime_remaining > 0)
+ unthrottle_cfs_rq(cfs_rq);
+
+next:
+ rq_unlock_irqrestore(rq, &rf);
+
+ if (!remaining)
+ break;
+ }
+ rcu_read_unlock();
+
+ return starting_runtime - remaining;
+}
+
+/*
+ * Responsible for refilling a task_group's bandwidth and unthrottling its
+ * cfs_rqs as appropriate. If there has been no activity within the last
+ * period the timer is deactivated until scheduling resumes; cfs_b->idle is
+ * used to track this state.
+ */
+static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun, unsigned long flags)
+{
+ u64 runtime;
+ int throttled;
+
+ /* no need to continue the timer with no bandwidth constraint */
+ if (cfs_b->quota == RUNTIME_INF)
+ goto out_deactivate;
+
+ throttled = !list_empty(&cfs_b->throttled_cfs_rq);
+ cfs_b->nr_periods += overrun;
+
+ /*
+ * idle depends on !throttled (for the case of a large deficit), and if
+ * we're going inactive then everything else can be deferred
+ */
+ if (cfs_b->idle && !throttled)
+ goto out_deactivate;
+
+ __refill_cfs_bandwidth_runtime(cfs_b);
+
+ if (!throttled) {
+ /* mark as potentially idle for the upcoming period */
+ cfs_b->idle = 1;
+ return 0;
+ }
+
+ /* account preceding periods in which throttling occurred */
+ cfs_b->nr_throttled += overrun;
+
+ /*
+ * This check is repeated as we are holding onto the new bandwidth while
+ * we unthrottle. This can potentially race with an unthrottled group
+ * trying to acquire new bandwidth from the global pool. This can result
+ * in us over-using our runtime if it is all used during this loop, but
+ * only by limited amounts in that extreme case.
+ */
+ while (throttled && cfs_b->runtime > 0 && !cfs_b->distribute_running) {
+ runtime = cfs_b->runtime;
+ cfs_b->distribute_running = 1;
+ raw_spin_unlock_irqrestore(&cfs_b->lock, flags);
+ /* we can't nest cfs_b->lock while distributing bandwidth */
+ runtime = distribute_cfs_runtime(cfs_b, runtime);
+ raw_spin_lock_irqsave(&cfs_b->lock, flags);
+
+ cfs_b->distribute_running = 0;
+ throttled = !list_empty(&cfs_b->throttled_cfs_rq);
+
+ lsub_positive(&cfs_b->runtime, runtime);
+ }
+
+ /*
+ * While we are ensured activity in the period following an
+ * unthrottle, this also covers the case in which the new bandwidth is
+ * insufficient to cover the existing bandwidth deficit. (Forcing the
+ * timer to remain active while there are any throttled entities.)
+ */
+ cfs_b->idle = 0;
+
+ return 0;
+
+out_deactivate:
+ return 1;
+}
+
+/* a cfs_rq won't donate quota below this amount */
+static const u64 min_cfs_rq_runtime = 1 * NSEC_PER_MSEC;
+/* minimum remaining period time to redistribute slack quota */
+static const u64 min_bandwidth_expiration = 2 * NSEC_PER_MSEC;
+/* how long we wait to gather additional slack before distributing */
+static const u64 cfs_bandwidth_slack_period = 5 * NSEC_PER_MSEC;
+
+/*
+ * Are we near the end of the current quota period?
+ *
+ * Requires cfs_b->lock for hrtimer_expires_remaining to be safe against the
+ * hrtimer base being cleared by hrtimer_start. In the case of
+ * migrate_hrtimers, base is never cleared, so we are fine.
+ */
+static int runtime_refresh_within(struct cfs_bandwidth *cfs_b, u64 min_expire)
+{
+ struct hrtimer *refresh_timer = &cfs_b->period_timer;
+ s64 remaining;
+
+ /* if the call-back is running a quota refresh is already occurring */
+ if (hrtimer_callback_running(refresh_timer))
+ return 1;
+
+ /* is a quota refresh about to occur? */
+ remaining = ktime_to_ns(hrtimer_expires_remaining(refresh_timer));
+ if (remaining < (s64)min_expire)
+ return 1;
+
+ return 0;
+}
+
+static void start_cfs_slack_bandwidth(struct cfs_bandwidth *cfs_b)
+{
+ u64 min_left = cfs_bandwidth_slack_period + min_bandwidth_expiration;
+
+ /* if there's a quota refresh soon don't bother with slack */
+ if (runtime_refresh_within(cfs_b, min_left))
+ return;
+
+ /* don't push forwards an existing deferred unthrottle */
+ if (cfs_b->slack_started)
+ return;
+ cfs_b->slack_started = true;
+
+ hrtimer_start(&cfs_b->slack_timer,
+ ns_to_ktime(cfs_bandwidth_slack_period),
+ HRTIMER_MODE_REL);
+}
+
+/* we know any runtime found here is valid as update_curr() precedes return */
+static void __return_cfs_rq_runtime(struct cfs_rq *cfs_rq)
+{
+ struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg);
+ s64 slack_runtime = cfs_rq->runtime_remaining - min_cfs_rq_runtime;
+
+ if (slack_runtime <= 0)
+ return;
+
+ raw_spin_lock(&cfs_b->lock);
+ if (cfs_b->quota != RUNTIME_INF) {
+ cfs_b->runtime += slack_runtime;
+
+ /* we are under rq->lock, defer unthrottling using a timer */
+ if (cfs_b->runtime > sched_cfs_bandwidth_slice() &&
+ !list_empty(&cfs_b->throttled_cfs_rq))
+ start_cfs_slack_bandwidth(cfs_b);
+ }
+ raw_spin_unlock(&cfs_b->lock);
+
+ /* even if it's not valid for return we don't want to try again */
+ cfs_rq->runtime_remaining -= slack_runtime;
+}
+
+static __always_inline void return_cfs_rq_runtime(struct cfs_rq *cfs_rq)
+{
+ if (!cfs_bandwidth_used())
+ return;
+
+ if (!cfs_rq->runtime_enabled || cfs_rq->nr_running)
+ return;
+
+ __return_cfs_rq_runtime(cfs_rq);
+}
+
+/*
+ * This is done with a timer (instead of inline with bandwidth return) since
+ * it's necessary to juggle rq->locks to unthrottle their respective cfs_rqs.
+ */
+static void do_sched_cfs_slack_timer(struct cfs_bandwidth *cfs_b)
+{
+ u64 runtime = 0, slice = sched_cfs_bandwidth_slice();
+ unsigned long flags;
+
+ /* confirm we're still not at a refresh boundary */
+ raw_spin_lock_irqsave(&cfs_b->lock, flags);
+ cfs_b->slack_started = false;
+ if (cfs_b->distribute_running) {
+ raw_spin_unlock_irqrestore(&cfs_b->lock, flags);
+ return;
+ }
+
+ if (runtime_refresh_within(cfs_b, min_bandwidth_expiration)) {
+ raw_spin_unlock_irqrestore(&cfs_b->lock, flags);
+ return;
+ }
+
+ if (cfs_b->quota != RUNTIME_INF && cfs_b->runtime > slice)
+ runtime = cfs_b->runtime;
+
+ if (runtime)
+ cfs_b->distribute_running = 1;
+
+ raw_spin_unlock_irqrestore(&cfs_b->lock, flags);
+
+ if (!runtime)
+ return;
+
+ runtime = distribute_cfs_runtime(cfs_b, runtime);
+
+ raw_spin_lock_irqsave(&cfs_b->lock, flags);
+ lsub_positive(&cfs_b->runtime, runtime);
+ cfs_b->distribute_running = 0;
+ raw_spin_unlock_irqrestore(&cfs_b->lock, flags);
+}
+
+/*
+ * When a group wakes up we want to make sure that its quota is not already
+ * expired/exceeded, otherwise it may be allowed to steal additional ticks of
+ * runtime as update_curr() throttling can not not trigger until it's on-rq.
+ */
+static void check_enqueue_throttle(struct cfs_rq *cfs_rq)
+{
+ if (!cfs_bandwidth_used())
+ return;
+
+ /* an active group must be handled by the update_curr()->put() path */
+ if (!cfs_rq->runtime_enabled || cfs_rq->curr)
+ return;
+
+ /* ensure the group is not already throttled */
+ if (cfs_rq_throttled(cfs_rq))
+ return;
+
+ /* update runtime allocation */
+ account_cfs_rq_runtime(cfs_rq, 0);
+ if (cfs_rq->runtime_remaining <= 0)
+ throttle_cfs_rq(cfs_rq);
+}
+
+static void sync_throttle(struct task_group *tg, int cpu)
+{
+ struct cfs_rq *pcfs_rq, *cfs_rq;
+
+ if (!cfs_bandwidth_used())
+ return;
+
+ if (!tg->parent)
+ return;
+
+ cfs_rq = tg->cfs_rq[cpu];
+ pcfs_rq = tg->parent->cfs_rq[cpu];
+
+ cfs_rq->throttle_count = pcfs_rq->throttle_count;
+ cfs_rq->throttled_clock_pelt = rq_clock_pelt(cpu_rq(cpu));
+}
+
+/* conditionally throttle active cfs_rq's from put_prev_entity() */
+static bool check_cfs_rq_runtime(struct cfs_rq *cfs_rq)
+{
+ if (!cfs_bandwidth_used())
+ return false;
+
+ if (likely(!cfs_rq->runtime_enabled || cfs_rq->runtime_remaining > 0))
+ return false;
+
+ /*
+ * it's possible for a throttled entity to be forced into a running
+ * state (e.g. set_curr_task), in this case we're finished.
+ */
+ if (cfs_rq_throttled(cfs_rq))
+ return true;
+
+ return throttle_cfs_rq(cfs_rq);
+}
+
+static enum hrtimer_restart sched_cfs_slack_timer(struct hrtimer *timer)
+{
+ struct cfs_bandwidth *cfs_b =
+ container_of(timer, struct cfs_bandwidth, slack_timer);
+
+ do_sched_cfs_slack_timer(cfs_b);
+
+ return HRTIMER_NORESTART;
+}
+
+extern const u64 max_cfs_quota_period;
+
+static enum hrtimer_restart sched_cfs_period_timer(struct hrtimer *timer)
+{
+ struct cfs_bandwidth *cfs_b =
+ container_of(timer, struct cfs_bandwidth, period_timer);
+ unsigned long flags;
+ int overrun;
+ int idle = 0;
+ int count = 0;
+
+ raw_spin_lock_irqsave(&cfs_b->lock, flags);
+ for (;;) {
+ overrun = hrtimer_forward_now(timer, cfs_b->period);
+ if (!overrun)
+ break;
+
+ idle = do_sched_cfs_period_timer(cfs_b, overrun, flags);
+
+ if (++count > 3) {
+ u64 new, old = ktime_to_ns(cfs_b->period);
+
+ /*
+ * Grow period by a factor of 2 to avoid losing precision.
+ * Precision loss in the quota/period ratio can cause __cfs_schedulable
+ * to fail.
+ */
+ new = old * 2;
+ if (new < max_cfs_quota_period) {
+ cfs_b->period = ns_to_ktime(new);
+ cfs_b->quota *= 2;
+
+ pr_warn_ratelimited(
+ "cfs_period_timer[cpu%d]: period too short, scaling up (new cfs_period_us = %lld, cfs_quota_us = %lld)\n",
+ smp_processor_id(),
+ div_u64(new, NSEC_PER_USEC),
+ div_u64(cfs_b->quota, NSEC_PER_USEC));
+ } else {
+ pr_warn_ratelimited(
+ "cfs_period_timer[cpu%d]: period too short, but cannot scale up without losing precision (cfs_period_us = %lld, cfs_quota_us = %lld)\n",
+ smp_processor_id(),
+ div_u64(old, NSEC_PER_USEC),
+ div_u64(cfs_b->quota, NSEC_PER_USEC));
+ }
+
+ /* reset count so we don't come right back in here */
+ count = 0;
+ }
+ }
+ if (idle)
+ cfs_b->period_active = 0;
+ raw_spin_unlock_irqrestore(&cfs_b->lock, flags);
+
+ return idle ? HRTIMER_NORESTART : HRTIMER_RESTART;
+}
+
+void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b)
+{
+ raw_spin_lock_init(&cfs_b->lock);
+ cfs_b->runtime = 0;
+ cfs_b->quota = RUNTIME_INF;
+ cfs_b->period = ns_to_ktime(default_cfs_period());
+
+ INIT_LIST_HEAD(&cfs_b->throttled_cfs_rq);
+ hrtimer_init(&cfs_b->period_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
+ cfs_b->period_timer.function = sched_cfs_period_timer;
+ hrtimer_init(&cfs_b->slack_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+ cfs_b->slack_timer.function = sched_cfs_slack_timer;
+ cfs_b->distribute_running = 0;
+ cfs_b->slack_started = false;
+}
+
+static void init_cfs_rq_runtime(struct cfs_rq *cfs_rq)
+{
+ cfs_rq->runtime_enabled = 0;
+ INIT_LIST_HEAD(&cfs_rq->throttled_list);
+}
+
+void start_cfs_bandwidth(struct cfs_bandwidth *cfs_b)
+{
+ lockdep_assert_held(&cfs_b->lock);
+
+ if (cfs_b->period_active)
+ return;
+
+ cfs_b->period_active = 1;
+ hrtimer_forward_now(&cfs_b->period_timer, cfs_b->period);
+ hrtimer_start_expires(&cfs_b->period_timer, HRTIMER_MODE_ABS_PINNED);
+}
+
+static void destroy_cfs_bandwidth(struct cfs_bandwidth *cfs_b)
+{
+ /* init_cfs_bandwidth() was not called */
+ if (!cfs_b->throttled_cfs_rq.next)
+ return;
+
+ hrtimer_cancel(&cfs_b->period_timer);
+ hrtimer_cancel(&cfs_b->slack_timer);
+}
+
+/*
+ * Both these CPU hotplug callbacks race against unregister_fair_sched_group()
+ *
+ * The race is harmless, since modifying bandwidth settings of unhooked group
+ * bits doesn't do much.
+ */
+
+/* cpu online calback */
+static void __maybe_unused update_runtime_enabled(struct rq *rq)
+{
+ struct task_group *tg;
+
+ lockdep_assert_held(&rq->lock);
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(tg, &task_groups, list) {
+ struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
+ struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)];
+
+ raw_spin_lock(&cfs_b->lock);
+ cfs_rq->runtime_enabled = cfs_b->quota != RUNTIME_INF;
+ raw_spin_unlock(&cfs_b->lock);
+ }
+ rcu_read_unlock();
+}
+
+/* cpu offline callback */
+static void __maybe_unused unthrottle_offline_cfs_rqs(struct rq *rq)
+{
+ struct task_group *tg;
+
+ lockdep_assert_held(&rq->lock);
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(tg, &task_groups, list) {
+ struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)];
+
+ if (!cfs_rq->runtime_enabled)
+ continue;
+
+ /*
+ * clock_task is not advancing so we just need to make sure
+ * there's some valid quota amount
+ */
+ cfs_rq->runtime_remaining = 1;
+ /*
+ * Offline rq is schedulable till CPU is completely disabled
+ * in take_cpu_down(), so we prevent new cfs throttling here.
+ */
+ cfs_rq->runtime_enabled = 0;
+
+ if (cfs_rq_throttled(cfs_rq))
+ unthrottle_cfs_rq(cfs_rq);
+ }
+ rcu_read_unlock();
+}
+
+#else /* CONFIG_CFS_BANDWIDTH */
+
+static inline bool cfs_bandwidth_used(void)
+{
+ return false;
+}
+
+static void account_cfs_rq_runtime(struct cfs_rq *cfs_rq, u64 delta_exec) {}
+static bool check_cfs_rq_runtime(struct cfs_rq *cfs_rq) { return false; }
+static void check_enqueue_throttle(struct cfs_rq *cfs_rq) {}
+static inline void sync_throttle(struct task_group *tg, int cpu) {}
+static __always_inline void return_cfs_rq_runtime(struct cfs_rq *cfs_rq) {}
+
+static inline int cfs_rq_throttled(struct cfs_rq *cfs_rq)
+{
+ return 0;
+}
+
+static inline int throttled_hierarchy(struct cfs_rq *cfs_rq)
+{
+ return 0;
+}
+
+static inline int throttled_lb_pair(struct task_group *tg,
+ int src_cpu, int dest_cpu)
+{
+ return 0;
+}
+
+void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b) {}
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+static void init_cfs_rq_runtime(struct cfs_rq *cfs_rq) {}
+#endif
+
+static inline struct cfs_bandwidth *tg_cfs_bandwidth(struct task_group *tg)
+{
+ return NULL;
+}
+static inline void destroy_cfs_bandwidth(struct cfs_bandwidth *cfs_b) {}
+static inline void update_runtime_enabled(struct rq *rq) {}
+static inline void unthrottle_offline_cfs_rqs(struct rq *rq) {}
+
+#endif /* CONFIG_CFS_BANDWIDTH */
+
+/**************************************************
+ * CFS operations on tasks:
+ */
+
+#ifdef CONFIG_SCHED_HRTICK
+static void hrtick_start_fair(struct rq *rq, struct task_struct *p)
+{
+ struct sched_entity *se = &p->se;
+ struct cfs_rq *cfs_rq = cfs_rq_of(se);
+
+ SCHED_WARN_ON(task_rq(p) != rq);
+
+ if (rq->cfs.h_nr_running > 1) {
+ u64 slice = sched_slice(cfs_rq, se);
+ u64 ran = se->sum_exec_runtime - se->prev_sum_exec_runtime;
+ s64 delta = slice - ran;
+
+ if (delta < 0) {
+ if (rq->curr == p)
+ resched_curr(rq);
+ return;
+ }
+ hrtick_start(rq, delta);
+ }
+}
+
+/*
+ * called from enqueue/dequeue and updates the hrtick when the
+ * current task is from our class and nr_running is low enough
+ * to matter.
+ */
+static void hrtick_update(struct rq *rq)
+{
+ struct task_struct *curr = rq->curr;
+
+ if (!hrtick_enabled(rq) || curr->sched_class != &fair_sched_class)
+ return;
+
+ if (cfs_rq_of(&curr->se)->nr_running < sched_nr_latency)
+ hrtick_start_fair(rq, curr);
+}
+#else /* !CONFIG_SCHED_HRTICK */
+static inline void
+hrtick_start_fair(struct rq *rq, struct task_struct *p)
+{
+}
+
+static inline void hrtick_update(struct rq *rq)
+{
+}
+#endif
+
+#ifdef CONFIG_SMP
+static inline unsigned long cpu_util(int cpu);
+
+static inline bool cpu_overutilized(int cpu)
+{
+ return !fits_capacity(cpu_util(cpu), capacity_of(cpu));
+}
+
+static inline void update_overutilized_status(struct rq *rq)
+{
+ if (!READ_ONCE(rq->rd->overutilized) && cpu_overutilized(rq->cpu)) {
+ WRITE_ONCE(rq->rd->overutilized, SG_OVERUTILIZED);
+ trace_sched_overutilized_tp(rq->rd, SG_OVERUTILIZED);
+ }
+}
+#else
+static inline void update_overutilized_status(struct rq *rq) { }
+#endif
+
+/*
+ * The enqueue_task method is called before nr_running is
+ * increased. Here we update the fair scheduling stats and
+ * then put the task into the rbtree:
+ */
+static void
+enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
+{
+ struct cfs_rq *cfs_rq;
+ struct sched_entity *se = &p->se;
+ int idle_h_nr_running = task_has_idle_policy(p);
+ int task_new = !(flags & ENQUEUE_WAKEUP);
+
+ /*
+ * The code below (indirectly) updates schedutil which looks at
+ * the cfs_rq utilization to select a frequency.
+ * Let's add the task's estimated utilization to the cfs_rq's
+ * estimated utilization, before we update schedutil.
+ */
+ util_est_enqueue(&rq->cfs, p);
+
+ /*
+ * If in_iowait is set, the code below may not trigger any cpufreq
+ * utilization updates, so do it here explicitly with the IOWAIT flag
+ * passed.
+ */
+ if (p->in_iowait)
+ cpufreq_update_util(rq, SCHED_CPUFREQ_IOWAIT);
+
+ for_each_sched_entity(se) {
+ if (se->on_rq)
+ break;
+ cfs_rq = cfs_rq_of(se);
+ enqueue_entity(cfs_rq, se, flags);
+
+ cfs_rq->h_nr_running++;
+ cfs_rq->idle_h_nr_running += idle_h_nr_running;
+
+ /* end evaluation on encountering a throttled cfs_rq */
+ if (cfs_rq_throttled(cfs_rq))
+ goto enqueue_throttle;
+
+ flags = ENQUEUE_WAKEUP;
+ }
+
+ for_each_sched_entity(se) {
+ cfs_rq = cfs_rq_of(se);
+
+ update_load_avg(cfs_rq, se, UPDATE_TG);
+ update_cfs_group(se);
+
+ cfs_rq->h_nr_running++;
+ cfs_rq->idle_h_nr_running += idle_h_nr_running;
+
+ /* end evaluation on encountering a throttled cfs_rq */
+ if (cfs_rq_throttled(cfs_rq))
+ goto enqueue_throttle;
+
+ /*
+ * One parent has been throttled and cfs_rq removed from the
+ * list. Add it back to not break the leaf list.
+ */
+ if (throttled_hierarchy(cfs_rq))
+ list_add_leaf_cfs_rq(cfs_rq);
+ }
+
+enqueue_throttle:
+ if (!se) {
+ add_nr_running(rq, 1);
+ /*
+ * Since new tasks are assigned an initial util_avg equal to
+ * half of the spare capacity of their CPU, tiny tasks have the
+ * ability to cross the overutilized threshold, which will
+ * result in the load balancer ruining all the task placement
+ * done by EAS. As a way to mitigate that effect, do not account
+ * for the first enqueue operation of new tasks during the
+ * overutilized flag detection.
+ *
+ * A better way of solving this problem would be to wait for
+ * the PELT signals of tasks to converge before taking them
+ * into account, but that is not straightforward to implement,
+ * and the following generally works well enough in practice.
+ */
+ if (!task_new)
+ update_overutilized_status(rq);
+
+ }
+
+ if (cfs_bandwidth_used()) {
+ /*
+ * When bandwidth control is enabled; the cfs_rq_throttled()
+ * breaks in the above iteration can result in incomplete
+ * leaf list maintenance, resulting in triggering the assertion
+ * below.
+ */
+ for_each_sched_entity(se) {
+ cfs_rq = cfs_rq_of(se);
+
+ if (list_add_leaf_cfs_rq(cfs_rq))
+ break;
+ }
+ }
+
+ assert_list_leaf_cfs_rq(rq);
+
+ hrtick_update(rq);
+}
+
+static void set_next_buddy(struct sched_entity *se);
+
+/*
+ * The dequeue_task method is called before nr_running is
+ * decreased. We remove the task from the rbtree and
+ * update the fair scheduling stats:
+ */
+static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags)
+{
+ struct cfs_rq *cfs_rq;
+ struct sched_entity *se = &p->se;
+ int task_sleep = flags & DEQUEUE_SLEEP;
+ int idle_h_nr_running = task_has_idle_policy(p);
+
+ for_each_sched_entity(se) {
+ cfs_rq = cfs_rq_of(se);
+ dequeue_entity(cfs_rq, se, flags);
+
+ cfs_rq->h_nr_running--;
+ cfs_rq->idle_h_nr_running -= idle_h_nr_running;
+
+ /* end evaluation on encountering a throttled cfs_rq */
+ if (cfs_rq_throttled(cfs_rq))
+ goto dequeue_throttle;
+
+ /* Don't dequeue parent if it has other entities besides us */
+ if (cfs_rq->load.weight) {
+ /* Avoid re-evaluating load for this entity: */
+ se = parent_entity(se);
+ /*
+ * Bias pick_next to pick a task from this cfs_rq, as
+ * p is sleeping when it is within its sched_slice.
+ */
+ if (task_sleep && se && !throttled_hierarchy(cfs_rq))
+ set_next_buddy(se);
+ break;
+ }
+ flags |= DEQUEUE_SLEEP;
+ }
+
+ for_each_sched_entity(se) {
+ cfs_rq = cfs_rq_of(se);
+
+ update_load_avg(cfs_rq, se, UPDATE_TG);
+ update_cfs_group(se);
+
+ cfs_rq->h_nr_running--;
+ cfs_rq->idle_h_nr_running -= idle_h_nr_running;
+
+ /* end evaluation on encountering a throttled cfs_rq */
+ if (cfs_rq_throttled(cfs_rq))
+ goto dequeue_throttle;
+
+ }
+
+dequeue_throttle:
+ if (!se)
+ sub_nr_running(rq, 1);
+
+ util_est_dequeue(&rq->cfs, p, task_sleep);
+ hrtick_update(rq);
+}
+
+#ifdef CONFIG_SMP
+
+/* Working cpumask for: load_balance, load_balance_newidle. */
+DEFINE_PER_CPU(cpumask_var_t, load_balance_mask);
+DEFINE_PER_CPU(cpumask_var_t, select_idle_mask);
+
+#ifdef CONFIG_NO_HZ_COMMON
+
+static struct {
+ cpumask_var_t idle_cpus_mask;
+ atomic_t nr_cpus;
+ int has_blocked; /* Idle CPUS has blocked load */
+ unsigned long next_balance; /* in jiffy units */
+ unsigned long next_blocked; /* Next update of blocked load in jiffies */
+} nohz ____cacheline_aligned;
+
+#endif /* CONFIG_NO_HZ_COMMON */
+
+/* CPU only has SCHED_IDLE tasks enqueued */
+static int sched_idle_cpu(int cpu)
+{
+ struct rq *rq = cpu_rq(cpu);
+
+ return unlikely(rq->nr_running == rq->cfs.idle_h_nr_running &&
+ rq->nr_running);
+}
+
+static unsigned long cpu_runnable_load(struct rq *rq)
+{
+ return cfs_rq_runnable_load_avg(&rq->cfs);
+}
+
+static unsigned long capacity_of(int cpu)
+{
+ return cpu_rq(cpu)->cpu_capacity;
+}
+
+static unsigned long cpu_avg_load_per_task(int cpu)
+{
+ struct rq *rq = cpu_rq(cpu);
+ unsigned long nr_running = READ_ONCE(rq->cfs.h_nr_running);
+ unsigned long load_avg = cpu_runnable_load(rq);
+
+ if (nr_running)
+ return load_avg / nr_running;
+
+ return 0;
+}
+
+static void record_wakee(struct task_struct *p)
+{
+ /*
+ * Only decay a single time; tasks that have less then 1 wakeup per
+ * jiffy will not have built up many flips.
+ */
+ if (time_after(jiffies, current->wakee_flip_decay_ts + HZ)) {
+ current->wakee_flips >>= 1;
+ current->wakee_flip_decay_ts = jiffies;
+ }
+
+ if (current->last_wakee != p) {
+ current->last_wakee = p;
+ current->wakee_flips++;
+ }
+}
+
+/*
+ * Detect M:N waker/wakee relationships via a switching-frequency heuristic.
+ *
+ * A waker of many should wake a different task than the one last awakened
+ * at a frequency roughly N times higher than one of its wakees.
+ *
+ * In order to determine whether we should let the load spread vs consolidating
+ * to shared cache, we look for a minimum 'flip' frequency of llc_size in one
+ * partner, and a factor of lls_size higher frequency in the other.
+ *
+ * With both conditions met, we can be relatively sure that the relationship is
+ * non-monogamous, with partner count exceeding socket size.
+ *
+ * Waker/wakee being client/server, worker/dispatcher, interrupt source or
+ * whatever is irrelevant, spread criteria is apparent partner count exceeds
+ * socket size.
+ */
+static int wake_wide(struct task_struct *p)
+{
+ unsigned int master = current->wakee_flips;
+ unsigned int slave = p->wakee_flips;
+ int factor = this_cpu_read(sd_llc_size);
+
+ if (master < slave)
+ swap(master, slave);
+ if (slave < factor || master < slave * factor)
+ return 0;
+ return 1;
+}
+
+/*
+ * The purpose of wake_affine() is to quickly determine on which CPU we can run
+ * soonest. For the purpose of speed we only consider the waking and previous
+ * CPU.
+ *
+ * wake_affine_idle() - only considers 'now', it check if the waking CPU is
+ * cache-affine and is (or will be) idle.
+ *
+ * wake_affine_weight() - considers the weight to reflect the average
+ * scheduling latency of the CPUs. This seems to work
+ * for the overloaded case.
+ */
+static int
+wake_affine_idle(int this_cpu, int prev_cpu, int sync)
+{
+ /*
+ * If this_cpu is idle, it implies the wakeup is from interrupt
+ * context. Only allow the move if cache is shared. Otherwise an
+ * interrupt intensive workload could force all tasks onto one
+ * node depending on the IO topology or IRQ affinity settings.
+ *
+ * If the prev_cpu is idle and cache affine then avoid a migration.
+ * There is no guarantee that the cache hot data from an interrupt
+ * is more important than cache hot data on the prev_cpu and from
+ * a cpufreq perspective, it's better to have higher utilisation
+ * on one CPU.
+ */
+ if (available_idle_cpu(this_cpu) && cpus_share_cache(this_cpu, prev_cpu))
+ return available_idle_cpu(prev_cpu) ? prev_cpu : this_cpu;
+
+ if (sync && cpu_rq(this_cpu)->nr_running == 1)
+ return this_cpu;
+
+ return nr_cpumask_bits;
+}
+
+static int
+wake_affine_weight(struct sched_domain *sd, struct task_struct *p,
+ int this_cpu, int prev_cpu, int sync)
+{
+ s64 this_eff_load, prev_eff_load;
+ unsigned long task_load;
+
+ this_eff_load = cpu_runnable_load(cpu_rq(this_cpu));
+
+ if (sync) {
+ unsigned long current_load = task_h_load(current);
+
+ if (current_load > this_eff_load)
+ return this_cpu;
+
+ this_eff_load -= current_load;
+ }
+
+ task_load = task_h_load(p);
+
+ this_eff_load += task_load;
+ if (sched_feat(WA_BIAS))
+ this_eff_load *= 100;
+ this_eff_load *= capacity_of(prev_cpu);
+
+ prev_eff_load = cpu_runnable_load(cpu_rq(prev_cpu));
+ prev_eff_load -= task_load;
+ if (sched_feat(WA_BIAS))
+ prev_eff_load *= 100 + (sd->imbalance_pct - 100) / 2;
+ prev_eff_load *= capacity_of(this_cpu);
+
+ /*
+ * If sync, adjust the weight of prev_eff_load such that if
+ * prev_eff == this_eff that select_idle_sibling() will consider
+ * stacking the wakee on top of the waker if no other CPU is
+ * idle.
+ */
+ if (sync)
+ prev_eff_load += 1;
+
+ return this_eff_load < prev_eff_load ? this_cpu : nr_cpumask_bits;
+}
+
+static int wake_affine(struct sched_domain *sd, struct task_struct *p,
+ int this_cpu, int prev_cpu, int sync)
+{
+ int target = nr_cpumask_bits;
+
+ if (sched_feat(WA_IDLE))
+ target = wake_affine_idle(this_cpu, prev_cpu, sync);
+
+ if (sched_feat(WA_WEIGHT) && target == nr_cpumask_bits)
+ target = wake_affine_weight(sd, p, this_cpu, prev_cpu, sync);
+
+ schedstat_inc(p->se.statistics.nr_wakeups_affine_attempts);
+ if (target == nr_cpumask_bits)
+ return prev_cpu;
+
+ schedstat_inc(sd->ttwu_move_affine);
+ schedstat_inc(p->se.statistics.nr_wakeups_affine);
+ return target;
+}
+
+static unsigned long cpu_util_without(int cpu, struct task_struct *p);
+
+static unsigned long capacity_spare_without(int cpu, struct task_struct *p)
+{
+ return max_t(long, capacity_of(cpu) - cpu_util_without(cpu, p), 0);
+}
+
+/*
+ * find_idlest_group finds and returns the least busy CPU group within the
+ * domain.
+ *
+ * Assumes p is allowed on at least one CPU in sd.
+ */
+static struct sched_group *
+find_idlest_group(struct sched_domain *sd, struct task_struct *p,
+ int this_cpu, int sd_flag)
+{
+ struct sched_group *idlest = NULL, *group = sd->groups;
+ struct sched_group *most_spare_sg = NULL;
+ unsigned long min_runnable_load = ULONG_MAX;
+ unsigned long this_runnable_load = ULONG_MAX;
+ unsigned long min_avg_load = ULONG_MAX, this_avg_load = ULONG_MAX;
+ unsigned long most_spare = 0, this_spare = 0;
+ int imbalance_scale = 100 + (sd->imbalance_pct-100)/2;
+ unsigned long imbalance = scale_load_down(NICE_0_LOAD) *
+ (sd->imbalance_pct-100) / 100;
+
+ do {
+ unsigned long load, avg_load, runnable_load;
+ unsigned long spare_cap, max_spare_cap;
+ int local_group;
+ int i;
+
+ /* Skip over this group if it has no CPUs allowed */
+ if (!cpumask_intersects(sched_group_span(group),
+ p->cpus_ptr))
+ continue;
+
+ local_group = cpumask_test_cpu(this_cpu,
+ sched_group_span(group));
+
+ /*
+ * Tally up the load of all CPUs in the group and find
+ * the group containing the CPU with most spare capacity.
+ */
+ avg_load = 0;
+ runnable_load = 0;
+ max_spare_cap = 0;
+
+ for_each_cpu(i, sched_group_span(group)) {
+ load = cpu_runnable_load(cpu_rq(i));
+ runnable_load += load;
+
+ avg_load += cfs_rq_load_avg(&cpu_rq(i)->cfs);
+
+ spare_cap = capacity_spare_without(i, p);
+
+ if (spare_cap > max_spare_cap)
+ max_spare_cap = spare_cap;
+ }
+
+ /* Adjust by relative CPU capacity of the group */
+ avg_load = (avg_load * SCHED_CAPACITY_SCALE) /
+ group->sgc->capacity;
+ runnable_load = (runnable_load * SCHED_CAPACITY_SCALE) /
+ group->sgc->capacity;
+
+ if (local_group) {
+ this_runnable_load = runnable_load;
+ this_avg_load = avg_load;
+ this_spare = max_spare_cap;
+ } else {
+ if (min_runnable_load > (runnable_load + imbalance)) {
+ /*
+ * The runnable load is significantly smaller
+ * so we can pick this new CPU:
+ */
+ min_runnable_load = runnable_load;
+ min_avg_load = avg_load;
+ idlest = group;
+ } else if ((runnable_load < (min_runnable_load + imbalance)) &&
+ (100*min_avg_load > imbalance_scale*avg_load)) {
+ /*
+ * The runnable loads are close so take the
+ * blocked load into account through avg_load:
+ */
+ min_avg_load = avg_load;
+ idlest = group;
+ }
+
+ if (most_spare < max_spare_cap) {
+ most_spare = max_spare_cap;
+ most_spare_sg = group;
+ }
+ }
+ } while (group = group->next, group != sd->groups);
+
+ /*
+ * The cross-over point between using spare capacity or least load
+ * is too conservative for high utilization tasks on partially
+ * utilized systems if we require spare_capacity > task_util(p),
+ * so we allow for some task stuffing by using
+ * spare_capacity > task_util(p)/2.
+ *
+ * Spare capacity can't be used for fork because the utilization has
+ * not been set yet, we must first select a rq to compute the initial
+ * utilization.
+ */
+ if (sd_flag & SD_BALANCE_FORK)
+ goto skip_spare;
+
+ if (this_spare > task_util(p) / 2 &&
+ imbalance_scale*this_spare > 100*most_spare)
+ return NULL;
+
+ if (most_spare > task_util(p) / 2)
+ return most_spare_sg;
+
+skip_spare:
+ if (!idlest)
+ return NULL;
+
+ /*
+ * When comparing groups across NUMA domains, it's possible for the
+ * local domain to be very lightly loaded relative to the remote
+ * domains but "imbalance" skews the comparison making remote CPUs
+ * look much more favourable. When considering cross-domain, add
+ * imbalance to the runnable load on the remote node and consider
+ * staying local.
+ */
+ if ((sd->flags & SD_NUMA) &&
+ min_runnable_load + imbalance >= this_runnable_load)
+ return NULL;
+
+ if (min_runnable_load > (this_runnable_load + imbalance))
+ return NULL;
+
+ if ((this_runnable_load < (min_runnable_load + imbalance)) &&
+ (100*this_avg_load < imbalance_scale*min_avg_load))
+ return NULL;
+
+ return idlest;
+}
+
+/*
+ * find_idlest_group_cpu - find the idlest CPU among the CPUs in the group.
+ */
+static int
+find_idlest_group_cpu(struct sched_group *group, struct task_struct *p, int this_cpu)
+{
+ unsigned long load, min_load = ULONG_MAX;
+ unsigned int min_exit_latency = UINT_MAX;
+ u64 latest_idle_timestamp = 0;
+ int least_loaded_cpu = this_cpu;
+ int shallowest_idle_cpu = -1, si_cpu = -1;
+ int i;
+
+ /* Check if we have any choice: */
+ if (group->group_weight == 1)
+ return cpumask_first(sched_group_span(group));
+
+ /* Traverse only the allowed CPUs */
+ for_each_cpu_and(i, sched_group_span(group), p->cpus_ptr) {
+ if (available_idle_cpu(i)) {
+ struct rq *rq = cpu_rq(i);
+ struct cpuidle_state *idle = idle_get_state(rq);
+ if (idle && idle->exit_latency < min_exit_latency) {
+ /*
+ * We give priority to a CPU whose idle state
+ * has the smallest exit latency irrespective
+ * of any idle timestamp.
+ */
+ min_exit_latency = idle->exit_latency;
+ latest_idle_timestamp = rq->idle_stamp;
+ shallowest_idle_cpu = i;
+ } else if ((!idle || idle->exit_latency == min_exit_latency) &&
+ rq->idle_stamp > latest_idle_timestamp) {
+ /*
+ * If equal or no active idle state, then
+ * the most recently idled CPU might have
+ * a warmer cache.
+ */
+ latest_idle_timestamp = rq->idle_stamp;
+ shallowest_idle_cpu = i;
+ }
+ } else if (shallowest_idle_cpu == -1 && si_cpu == -1) {
+ if (sched_idle_cpu(i)) {
+ si_cpu = i;
+ continue;
+ }
+
+ load = cpu_runnable_load(cpu_rq(i));
+ if (load < min_load) {
+ min_load = load;
+ least_loaded_cpu = i;
+ }
+ }
+ }
+
+ if (shallowest_idle_cpu != -1)
+ return shallowest_idle_cpu;
+ if (si_cpu != -1)
+ return si_cpu;
+ return least_loaded_cpu;
+}
+
+static inline int find_idlest_cpu(struct sched_domain *sd, struct task_struct *p,
+ int cpu, int prev_cpu, int sd_flag)
+{
+ int new_cpu = cpu;
+
+ if (!cpumask_intersects(sched_domain_span(sd), p->cpus_ptr))
+ return prev_cpu;
+
+ /*
+ * We need task's util for capacity_spare_without, sync it up to
+ * prev_cpu's last_update_time.
+ */
+ if (!(sd_flag & SD_BALANCE_FORK))
+ sync_entity_load_avg(&p->se);
+
+ while (sd) {
+ struct sched_group *group;
+ struct sched_domain *tmp;
+ int weight;
+
+ if (!(sd->flags & sd_flag)) {
+ sd = sd->child;
+ continue;
+ }
+
+ group = find_idlest_group(sd, p, cpu, sd_flag);
+ if (!group) {
+ sd = sd->child;
+ continue;
+ }
+
+ new_cpu = find_idlest_group_cpu(group, p, cpu);
+ if (new_cpu == cpu) {
+ /* Now try balancing at a lower domain level of 'cpu': */
+ sd = sd->child;
+ continue;
+ }
+
+ /* Now try balancing at a lower domain level of 'new_cpu': */
+ cpu = new_cpu;
+ weight = sd->span_weight;
+ sd = NULL;
+ for_each_domain(cpu, tmp) {
+ if (weight <= tmp->span_weight)
+ break;
+ if (tmp->flags & sd_flag)
+ sd = tmp;
+ }
+ }
+
+ return new_cpu;
+}
+
+#ifdef CONFIG_SCHED_SMT
+DEFINE_STATIC_KEY_FALSE(sched_smt_present);
+EXPORT_SYMBOL_GPL(sched_smt_present);
+
+static inline void set_idle_cores(int cpu, int val)
+{
+ struct sched_domain_shared *sds;
+
+ sds = rcu_dereference(per_cpu(sd_llc_shared, cpu));
+ if (sds)
+ WRITE_ONCE(sds->has_idle_cores, val);
+}
+
+static inline bool test_idle_cores(int cpu, bool def)
+{
+ struct sched_domain_shared *sds;
+
+ sds = rcu_dereference(per_cpu(sd_llc_shared, cpu));
+ if (sds)
+ return READ_ONCE(sds->has_idle_cores);
+
+ return def;
+}
+
+/*
+ * Scans the local SMT mask to see if the entire core is idle, and records this
+ * information in sd_llc_shared->has_idle_cores.
+ *
+ * Since SMT siblings share all cache levels, inspecting this limited remote
+ * state should be fairly cheap.
+ */
+void __update_idle_core(struct rq *rq)
+{
+ int core = cpu_of(rq);
+ int cpu;
+
+ rcu_read_lock();
+ if (test_idle_cores(core, true))
+ goto unlock;
+
+ for_each_cpu(cpu, cpu_smt_mask(core)) {
+ if (cpu == core)
+ continue;
+
+ if (!available_idle_cpu(cpu))
+ goto unlock;
+ }
+
+ set_idle_cores(core, 1);
+unlock:
+ rcu_read_unlock();
+}
+
+/*
+ * Scan the entire LLC domain for idle cores; this dynamically switches off if
+ * there are no idle cores left in the system; tracked through
+ * sd_llc->shared->has_idle_cores and enabled through update_idle_core() above.
+ */
+static int select_idle_core(struct task_struct *p, struct sched_domain *sd, int target)
+{
+ struct cpumask *cpus = this_cpu_cpumask_var_ptr(select_idle_mask);
+ int core, cpu;
+
+ if (!static_branch_likely(&sched_smt_present))
+ return -1;
+
+ if (!test_idle_cores(target, false))
+ return -1;
+
+ cpumask_and(cpus, sched_domain_span(sd), p->cpus_ptr);
+
+ for_each_cpu_wrap(core, cpus, target) {
+ bool idle = true;
+
+ for_each_cpu(cpu, cpu_smt_mask(core)) {
+ __cpumask_clear_cpu(cpu, cpus);
+ if (!available_idle_cpu(cpu))
+ idle = false;
+ }
+
+ if (idle)
+ return core;
+ }
+
+ /*
+ * Failed to find an idle core; stop looking for one.
+ */
+ set_idle_cores(target, 0);
+
+ return -1;
+}
+
+/*
+ * Scan the local SMT mask for idle CPUs.
+ */
+static int select_idle_smt(struct task_struct *p, struct sched_domain *sd, int target)
+{
+ int cpu, si_cpu = -1;
+
+ if (!static_branch_likely(&sched_smt_present))
+ return -1;
+
+ for_each_cpu(cpu, cpu_smt_mask(target)) {
+ if (!cpumask_test_cpu(cpu, p->cpus_ptr) ||
+ !cpumask_test_cpu(cpu, sched_domain_span(sd)))
+ continue;
+ if (available_idle_cpu(cpu))
+ return cpu;
+ if (si_cpu == -1 && sched_idle_cpu(cpu))
+ si_cpu = cpu;
+ }
+
+ return si_cpu;
+}
+
+#else /* CONFIG_SCHED_SMT */
+
+static inline int select_idle_core(struct task_struct *p, struct sched_domain *sd, int target)
+{
+ return -1;
+}
+
+static inline int select_idle_smt(struct task_struct *p, struct sched_domain *sd, int target)
+{
+ return -1;
+}
+
+#endif /* CONFIG_SCHED_SMT */
+
+/*
+ * Scan the LLC domain for idle CPUs; this is dynamically regulated by
+ * comparing the average scan cost (tracked in sd->avg_scan_cost) against the
+ * average idle time for this rq (as found in rq->avg_idle).
+ */
+static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, int target)
+{
+ struct cpumask *cpus = this_cpu_cpumask_var_ptr(select_idle_mask);
+ struct sched_domain *this_sd;
+ u64 avg_cost, avg_idle;
+ u64 time, cost;
+ s64 delta;
+ int this = smp_processor_id();
+ int cpu, nr = INT_MAX, si_cpu = -1;
+
+ this_sd = rcu_dereference(*this_cpu_ptr(&sd_llc));
+ if (!this_sd)
+ return -1;
+
+ /*
+ * Due to large variance we need a large fuzz factor; hackbench in
+ * particularly is sensitive here.
+ */
+ avg_idle = this_rq()->avg_idle / 512;
+ avg_cost = this_sd->avg_scan_cost + 1;
+
+ if (sched_feat(SIS_AVG_CPU) && avg_idle < avg_cost)
+ return -1;
+
+ if (sched_feat(SIS_PROP)) {
+ u64 span_avg = sd->span_weight * avg_idle;
+ if (span_avg > 4*avg_cost)
+ nr = div_u64(span_avg, avg_cost);
+ else
+ nr = 4;
+ }
+
+ time = cpu_clock(this);
+
+ cpumask_and(cpus, sched_domain_span(sd), p->cpus_ptr);
+
+ for_each_cpu_wrap(cpu, cpus, target) {
+ if (!--nr)
+ return si_cpu;
+ if (available_idle_cpu(cpu))
+ break;
+ if (si_cpu == -1 && sched_idle_cpu(cpu))
+ si_cpu = cpu;
+ }
+
+ time = cpu_clock(this) - time;
+ cost = this_sd->avg_scan_cost;
+ delta = (s64)(time - cost) / 8;
+ this_sd->avg_scan_cost += delta;
+
+ return cpu;
+}
+
+/*
+ * Scan the asym_capacity domain for idle CPUs; pick the first idle one on which
+ * the task fits. If no CPU is big enough, but there are idle ones, try to
+ * maximize capacity.
+ */
+static int
+select_idle_capacity(struct task_struct *p, struct sched_domain *sd, int target)
+{
+ unsigned long task_util, best_cap = 0;
+ int cpu, best_cpu = -1;
+ struct cpumask *cpus;
+
+ cpus = this_cpu_cpumask_var_ptr(select_idle_mask);
+ cpumask_and(cpus, sched_domain_span(sd), p->cpus_ptr);
+
+ task_util = uclamp_task_util(p);
+
+ for_each_cpu_wrap(cpu, cpus, target) {
+ unsigned long cpu_cap = capacity_of(cpu);
+
+ if (!available_idle_cpu(cpu) && !sched_idle_cpu(cpu))
+ continue;
+ if (fits_capacity(task_util, cpu_cap))
+ return cpu;
+
+ if (cpu_cap > best_cap) {
+ best_cap = cpu_cap;
+ best_cpu = cpu;
+ }
+ }
+
+ return best_cpu;
+}
+
+static inline bool asym_fits_capacity(int task_util, int cpu)
+{
+ if (static_branch_unlikely(&sched_asym_cpucapacity))
+ return fits_capacity(task_util, capacity_of(cpu));
+
+ return true;
+}
+
+/*
+ * Try and locate an idle core/thread in the LLC cache domain.
+ */
+static int select_idle_sibling(struct task_struct *p, int prev, int target)
+{
+ struct sched_domain *sd;
+ unsigned long task_util;
+ int i, recent_used_cpu;
+
+ /*
+ * On asymmetric system, update task utilization because we will check
+ * that the task fits with cpu's capacity.
+ */
+ if (static_branch_unlikely(&sched_asym_cpucapacity)) {
+ sync_entity_load_avg(&p->se);
+ task_util = uclamp_task_util(p);
+ }
+
+ if ((available_idle_cpu(target) || sched_idle_cpu(target)) &&
+ asym_fits_capacity(task_util, target))
+ return target;
+
+ /*
+ * If the previous CPU is cache affine and idle, don't be stupid:
+ */
+ if (prev != target && cpus_share_cache(prev, target) &&
+ (available_idle_cpu(prev) || sched_idle_cpu(prev)) &&
+ asym_fits_capacity(task_util, prev))
+ return prev;
+
+ /* Check a recently used CPU as a potential idle candidate: */
+ recent_used_cpu = p->recent_used_cpu;
+ if (recent_used_cpu != prev &&
+ recent_used_cpu != target &&
+ cpus_share_cache(recent_used_cpu, target) &&
+ (available_idle_cpu(recent_used_cpu) || sched_idle_cpu(recent_used_cpu)) &&
+ cpumask_test_cpu(p->recent_used_cpu, p->cpus_ptr) &&
+ asym_fits_capacity(task_util, recent_used_cpu)) {
+ /*
+ * Replace recent_used_cpu with prev as it is a potential
+ * candidate for the next wake:
+ */
+ p->recent_used_cpu = prev;
+ return recent_used_cpu;
+ }
+
+ /*
+ * For asymmetric CPU capacity systems, our domain of interest is
+ * sd_asym_cpucapacity rather than sd_llc.
+ */
+ if (static_branch_unlikely(&sched_asym_cpucapacity)) {
+ sd = rcu_dereference(per_cpu(sd_asym_cpucapacity, target));
+ /*
+ * On an asymmetric CPU capacity system where an exclusive
+ * cpuset defines a symmetric island (i.e. one unique
+ * capacity_orig value through the cpuset), the key will be set
+ * but the CPUs within that cpuset will not have a domain with
+ * SD_ASYM_CPUCAPACITY. These should follow the usual symmetric
+ * capacity path.
+ */
+ if (sd) {
+ i = select_idle_capacity(p, sd, target);
+ return ((unsigned)i < nr_cpumask_bits) ? i : target;
+ }
+ }
+
+ sd = rcu_dereference(per_cpu(sd_llc, target));
+ if (!sd)
+ return target;
+
+ i = select_idle_core(p, sd, target);
+ if ((unsigned)i < nr_cpumask_bits)
+ return i;
+
+ i = select_idle_cpu(p, sd, target);
+ if ((unsigned)i < nr_cpumask_bits)
+ return i;
+
+ i = select_idle_smt(p, sd, target);
+ if ((unsigned)i < nr_cpumask_bits)
+ return i;
+
+ return target;
+}
+
+/**
+ * Amount of capacity of a CPU that is (estimated to be) used by CFS tasks
+ * @cpu: the CPU to get the utilization of
+ *
+ * The unit of the return value must be the one of capacity so we can compare
+ * the utilization with the capacity of the CPU that is available for CFS task
+ * (ie cpu_capacity).
+ *
+ * cfs_rq.avg.util_avg is the sum of running time of runnable tasks plus the
+ * recent utilization of currently non-runnable tasks on a CPU. It represents
+ * the amount of utilization of a CPU in the range [0..capacity_orig] where
+ * capacity_orig is the cpu_capacity available at the highest frequency
+ * (arch_scale_freq_capacity()).
+ * The utilization of a CPU converges towards a sum equal to or less than the
+ * current capacity (capacity_curr <= capacity_orig) of the CPU because it is
+ * the running time on this CPU scaled by capacity_curr.
+ *
+ * The estimated utilization of a CPU is defined to be the maximum between its
+ * cfs_rq.avg.util_avg and the sum of the estimated utilization of the tasks
+ * currently RUNNABLE on that CPU.
+ * This allows to properly represent the expected utilization of a CPU which
+ * has just got a big task running since a long sleep period. At the same time
+ * however it preserves the benefits of the "blocked utilization" in
+ * describing the potential for other tasks waking up on the same CPU.
+ *
+ * Nevertheless, cfs_rq.avg.util_avg can be higher than capacity_curr or even
+ * higher than capacity_orig because of unfortunate rounding in
+ * cfs.avg.util_avg or just after migrating tasks and new task wakeups until
+ * the average stabilizes with the new running time. We need to check that the
+ * utilization stays within the range of [0..capacity_orig] and cap it if
+ * necessary. Without utilization capping, a group could be seen as overloaded
+ * (CPU0 utilization at 121% + CPU1 utilization at 80%) whereas CPU1 has 20% of
+ * available capacity. We allow utilization to overshoot capacity_curr (but not
+ * capacity_orig) as it useful for predicting the capacity required after task
+ * migrations (scheduler-driven DVFS).
+ *
+ * Return: the (estimated) utilization for the specified CPU
+ */
+static inline unsigned long cpu_util(int cpu)
+{
+ struct cfs_rq *cfs_rq;
+ unsigned int util;
+
+ cfs_rq = &cpu_rq(cpu)->cfs;
+ util = READ_ONCE(cfs_rq->avg.util_avg);
+
+ if (sched_feat(UTIL_EST))
+ util = max(util, READ_ONCE(cfs_rq->avg.util_est.enqueued));
+
+ return min_t(unsigned long, util, capacity_orig_of(cpu));
+}
+
+/*
+ * cpu_util_without: compute cpu utilization without any contributions from *p
+ * @cpu: the CPU which utilization is requested
+ * @p: the task which utilization should be discounted
+ *
+ * The utilization of a CPU is defined by the utilization of tasks currently
+ * enqueued on that CPU as well as tasks which are currently sleeping after an
+ * execution on that CPU.
+ *
+ * This method returns the utilization of the specified CPU by discounting the
+ * utilization of the specified task, whenever the task is currently
+ * contributing to the CPU utilization.
+ */
+static unsigned long cpu_util_without(int cpu, struct task_struct *p)
+{
+ struct cfs_rq *cfs_rq;
+ unsigned int util;
+
+ /* Task has no contribution or is new */
+ if (cpu != task_cpu(p) || !READ_ONCE(p->se.avg.last_update_time))
+ return cpu_util(cpu);
+
+ cfs_rq = &cpu_rq(cpu)->cfs;
+ util = READ_ONCE(cfs_rq->avg.util_avg);
+
+ /* Discount task's util from CPU's util */
+ lsub_positive(&util, task_util(p));
+
+ /*
+ * Covered cases:
+ *
+ * a) if *p is the only task sleeping on this CPU, then:
+ * cpu_util (== task_util) > util_est (== 0)
+ * and thus we return:
+ * cpu_util_without = (cpu_util - task_util) = 0
+ *
+ * b) if other tasks are SLEEPING on this CPU, which is now exiting
+ * IDLE, then:
+ * cpu_util >= task_util
+ * cpu_util > util_est (== 0)
+ * and thus we discount *p's blocked utilization to return:
+ * cpu_util_without = (cpu_util - task_util) >= 0
+ *
+ * c) if other tasks are RUNNABLE on that CPU and
+ * util_est > cpu_util
+ * then we use util_est since it returns a more restrictive
+ * estimation of the spare capacity on that CPU, by just
+ * considering the expected utilization of tasks already
+ * runnable on that CPU.
+ *
+ * Cases a) and b) are covered by the above code, while case c) is
+ * covered by the following code when estimated utilization is
+ * enabled.
+ */
+ if (sched_feat(UTIL_EST)) {
+ unsigned int estimated =
+ READ_ONCE(cfs_rq->avg.util_est.enqueued);
+
+ /*
+ * Despite the following checks we still have a small window
+ * for a possible race, when an execl's select_task_rq_fair()
+ * races with LB's detach_task():
+ *
+ * detach_task()
+ * p->on_rq = TASK_ON_RQ_MIGRATING;
+ * ---------------------------------- A
+ * deactivate_task() \
+ * dequeue_task() + RaceTime
+ * util_est_dequeue() /
+ * ---------------------------------- B
+ *
+ * The additional check on "current == p" it's required to
+ * properly fix the execl regression and it helps in further
+ * reducing the chances for the above race.
+ */
+ if (unlikely(task_on_rq_queued(p) || current == p))
+ lsub_positive(&estimated, _task_util_est(p));
+
+ util = max(util, estimated);
+ }
+
+ /*
+ * Utilization (estimated) can exceed the CPU capacity, thus let's
+ * clamp to the maximum CPU capacity to ensure consistency with
+ * the cpu_util call.
+ */
+ return min_t(unsigned long, util, capacity_orig_of(cpu));
+}
+
+/*
+ * Predicts what cpu_util(@cpu) would return if @p was migrated (and enqueued)
+ * to @dst_cpu.
+ */
+static unsigned long cpu_util_next(int cpu, struct task_struct *p, int dst_cpu)
+{
+ struct cfs_rq *cfs_rq = &cpu_rq(cpu)->cfs;
+ unsigned long util_est, util = READ_ONCE(cfs_rq->avg.util_avg);
+
+ /*
+ * If @p migrates from @cpu to another, remove its contribution. Or,
+ * if @p migrates from another CPU to @cpu, add its contribution. In
+ * the other cases, @cpu is not impacted by the migration, so the
+ * util_avg should already be correct.
+ */
+ if (task_cpu(p) == cpu && dst_cpu != cpu)
+ sub_positive(&util, task_util(p));
+ else if (task_cpu(p) != cpu && dst_cpu == cpu)
+ util += task_util(p);
+
+ if (sched_feat(UTIL_EST)) {
+ util_est = READ_ONCE(cfs_rq->avg.util_est.enqueued);
+
+ /*
+ * During wake-up, the task isn't enqueued yet and doesn't
+ * appear in the cfs_rq->avg.util_est.enqueued of any rq,
+ * so just add it (if needed) to "simulate" what will be
+ * cpu_util() after the task has been enqueued.
+ */
+ if (dst_cpu == cpu)
+ util_est += _task_util_est(p);
+
+ util = max(util, util_est);
+ }
+
+ return min(util, capacity_orig_of(cpu));
+}
+
+/*
+ * compute_energy(): Estimates the energy that @pd would consume if @p was
+ * migrated to @dst_cpu. compute_energy() predicts what will be the utilization
+ * landscape of @pd's CPUs after the task migration, and uses the Energy Model
+ * to compute what would be the energy if we decided to actually migrate that
+ * task.
+ */
+static long
+compute_energy(struct task_struct *p, int dst_cpu, struct perf_domain *pd)
+{
+ struct cpumask *pd_mask = perf_domain_span(pd);
+ unsigned long cpu_cap = arch_scale_cpu_capacity(cpumask_first(pd_mask));
+ unsigned long max_util = 0, sum_util = 0;
+ unsigned long energy = 0;
+ int cpu;
+
+ /*
+ * The capacity state of CPUs of the current rd can be driven by CPUs
+ * of another rd if they belong to the same pd. So, account for the
+ * utilization of these CPUs too by masking pd with cpu_online_mask
+ * instead of the rd span.
+ *
+ * If an entire pd is outside of the current rd, it will not appear in
+ * its pd list and will not be accounted by compute_energy().
+ */
+ for_each_cpu_and(cpu, pd_mask, cpu_online_mask) {
+ unsigned long cpu_util, util_cfs = cpu_util_next(cpu, p, dst_cpu);
+ struct task_struct *tsk = cpu == dst_cpu ? p : NULL;
+
+ /*
+ * Busy time computation: utilization clamping is not
+ * required since the ratio (sum_util / cpu_capacity)
+ * is already enough to scale the EM reported power
+ * consumption at the (eventually clamped) cpu_capacity.
+ */
+ sum_util += schedutil_cpu_util(cpu, util_cfs, cpu_cap,
+ ENERGY_UTIL, NULL);
+
+ /*
+ * Performance domain frequency: utilization clamping
+ * must be considered since it affects the selection
+ * of the performance domain frequency.
+ * NOTE: in case RT tasks are running, by default the
+ * FREQUENCY_UTIL's utilization can be max OPP.
+ */
+ cpu_util = schedutil_cpu_util(cpu, util_cfs, cpu_cap,
+ FREQUENCY_UTIL, tsk);
+ max_util = max(max_util, cpu_util);
+ }
+
+ trace_android_vh_em_pd_energy(pd->em_pd, max_util, sum_util, &energy);
+ if (!energy)
+ energy = em_pd_energy(pd->em_pd, max_util, sum_util);
+
+ return energy;
+}
+
+/*
+ * find_energy_efficient_cpu(): Find most energy-efficient target CPU for the
+ * waking task. find_energy_efficient_cpu() looks for the CPU with maximum
+ * spare capacity in each performance domain and uses it as a potential
+ * candidate to execute the task. Then, it uses the Energy Model to figure
+ * out which of the CPU candidates is the most energy-efficient.
+ *
+ * The rationale for this heuristic is as follows. In a performance domain,
+ * all the most energy efficient CPU candidates (according to the Energy
+ * Model) are those for which we'll request a low frequency. When there are
+ * several CPUs for which the frequency request will be the same, we don't
+ * have enough data to break the tie between them, because the Energy Model
+ * only includes active power costs. With this model, if we assume that
+ * frequency requests follow utilization (e.g. using schedutil), the CPU with
+ * the maximum spare capacity in a performance domain is guaranteed to be among
+ * the best candidates of the performance domain.
+ *
+ * In practice, it could be preferable from an energy standpoint to pack
+ * small tasks on a CPU in order to let other CPUs go in deeper idle states,
+ * but that could also hurt our chances to go cluster idle, and we have no
+ * ways to tell with the current Energy Model if this is actually a good
+ * idea or not. So, find_energy_efficient_cpu() basically favors
+ * cluster-packing, and spreading inside a cluster. That should at least be
+ * a good thing for latency, and this is consistent with the idea that most
+ * of the energy savings of EAS come from the asymmetry of the system, and
+ * not so much from breaking the tie between identical CPUs. That's also the
+ * reason why EAS is enabled in the topology code only for systems where
+ * SD_ASYM_CPUCAPACITY is set.
+ *
+ * NOTE: Forkees are not accepted in the energy-aware wake-up path because
+ * they don't have any useful utilization data yet and it's not possible to
+ * forecast their impact on energy consumption. Consequently, they will be
+ * placed by find_idlest_cpu() on the least loaded CPU, which might turn out
+ * to be energy-inefficient in some use-cases. The alternative would be to
+ * bias new tasks towards specific types of CPUs first, or to try to infer
+ * their util_avg from the parent task, but those heuristics could hurt
+ * other use-cases too. So, until someone finds a better way to solve this,
+ * let's keep things simple by re-using the existing slow path.
+ */
+static int find_energy_efficient_cpu(struct task_struct *p, int prev_cpu, int sync)
+{
+ unsigned long prev_delta = ULONG_MAX, best_delta = ULONG_MAX;
+ struct root_domain *rd = cpu_rq(smp_processor_id())->rd;
+ int max_spare_cap_cpu_ls = prev_cpu, best_idle_cpu = -1;
+ unsigned long max_spare_cap_ls = 0, target_cap;
+ unsigned long cpu_cap, util, base_energy = 0;
+ bool boosted, latency_sensitive = false;
+ unsigned int min_exit_lat = UINT_MAX;
+ int cpu, best_energy_cpu = prev_cpu;
+ struct cpuidle_state *idle;
+ struct sched_domain *sd;
+ struct perf_domain *pd;
+
+ rcu_read_lock();
+ pd = rcu_dereference(rd->pd);
+ if (!pd || READ_ONCE(rd->overutilized))
+ goto fail;
+
+ cpu = smp_processor_id();
+ if (sync && cpu_rq(cpu)->nr_running == 1 &&
+ cpumask_test_cpu(cpu, p->cpus_ptr)) {
+ rcu_read_unlock();
+ return cpu;
+ }
+
+ /*
+ * Energy-aware wake-up happens on the lowest sched_domain starting
+ * from sd_asym_cpucapacity spanning over this_cpu and prev_cpu.
+ */
+ sd = rcu_dereference(*this_cpu_ptr(&sd_asym_cpucapacity));
+ while (sd && !cpumask_test_cpu(prev_cpu, sched_domain_span(sd)))
+ sd = sd->parent;
+ if (!sd)
+ goto fail;
+
+ sync_entity_load_avg(&p->se);
+ if (!task_util_est(p))
+ goto unlock;
+
+ latency_sensitive = uclamp_latency_sensitive(p);
+ boosted = uclamp_boosted(p);
+ target_cap = boosted ? 0 : ULONG_MAX;
+
+ for (; pd; pd = pd->next) {
+ unsigned long cur_delta, spare_cap, max_spare_cap = 0;
+ unsigned long base_energy_pd;
+ int max_spare_cap_cpu = -1;
+
+ /* Compute the 'base' energy of the pd, without @p */
+ base_energy_pd = compute_energy(p, -1, pd);
+ base_energy += base_energy_pd;
+
+ for_each_cpu_and(cpu, perf_domain_span(pd), sched_domain_span(sd)) {
+ if (!cpumask_test_cpu(cpu, p->cpus_ptr))
+ continue;
+
+ util = cpu_util_next(cpu, p, cpu);
+ cpu_cap = capacity_of(cpu);
+ spare_cap = cpu_cap;
+ lsub_positive(&spare_cap, util);
+
+ /*
+ * Skip CPUs that cannot satisfy the capacity request.
+ * IOW, placing the task there would make the CPU
+ * overutilized. Take uclamp into account to see how
+ * much capacity we can get out of the CPU; this is
+ * aligned with schedutil_cpu_util().
+ */
+ util = uclamp_rq_util_with(cpu_rq(cpu), util, p);
+ if (!fits_capacity(util, cpu_cap))
+ continue;
+
+ /* Always use prev_cpu as a candidate. */
+ if (!latency_sensitive && cpu == prev_cpu) {
+ prev_delta = compute_energy(p, prev_cpu, pd);
+ prev_delta -= base_energy_pd;
+ best_delta = min(best_delta, prev_delta);
+ }
+
+ /*
+ * Find the CPU with the maximum spare capacity in
+ * the performance domain
+ */
+ if (spare_cap > max_spare_cap) {
+ max_spare_cap = spare_cap;
+ max_spare_cap_cpu = cpu;
+ }
+
+ if (!latency_sensitive)
+ continue;
+
+ if (idle_cpu(cpu)) {
+ cpu_cap = capacity_orig_of(cpu);
+ if (boosted && cpu_cap < target_cap)
+ continue;
+ if (!boosted && cpu_cap > target_cap)
+ continue;
+ idle = idle_get_state(cpu_rq(cpu));
+ if (idle && idle->exit_latency > min_exit_lat &&
+ cpu_cap == target_cap)
+ continue;
+
+ if (idle)
+ min_exit_lat = idle->exit_latency;
+ target_cap = cpu_cap;
+ best_idle_cpu = cpu;
+ } else if (spare_cap > max_spare_cap_ls) {
+ max_spare_cap_ls = spare_cap;
+ max_spare_cap_cpu_ls = cpu;
+ }
+ }
+
+ /* Evaluate the energy impact of using this CPU. */
+ if (!latency_sensitive && max_spare_cap_cpu >= 0 &&
+ max_spare_cap_cpu != prev_cpu) {
+ cur_delta = compute_energy(p, max_spare_cap_cpu, pd);
+ cur_delta -= base_energy_pd;
+ if (cur_delta < best_delta) {
+ best_delta = cur_delta;
+ best_energy_cpu = max_spare_cap_cpu;
+ }
+ }
+ }
+unlock:
+ rcu_read_unlock();
+
+ if (latency_sensitive)
+ return best_idle_cpu >= 0 ? best_idle_cpu : max_spare_cap_cpu_ls;
+
+ /*
+ * Pick the best CPU if prev_cpu cannot be used, or if it saves at
+ * least 6% of the energy used by prev_cpu.
+ */
+ if (prev_delta == ULONG_MAX)
+ return best_energy_cpu;
+
+ if ((prev_delta - best_delta) > ((prev_delta + base_energy) >> 4))
+ return best_energy_cpu;
+
+ return prev_cpu;
+
+fail:
+ rcu_read_unlock();
+
+ return -1;
+}
+
+/*
+ * select_task_rq_fair: Select target runqueue for the waking task in domains
+ * that have the 'sd_flag' flag set. In practice, this is SD_BALANCE_WAKE,
+ * SD_BALANCE_FORK, or SD_BALANCE_EXEC.
+ *
+ * Balances load by selecting the idlest CPU in the idlest group, or under
+ * certain conditions an idle sibling CPU if the domain has SD_WAKE_AFFINE set.
+ *
+ * Returns the target CPU number.
+ *
+ * preempt must be disabled.
+ */
+static int
+select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_flags)
+{
+ struct sched_domain *tmp, *sd = NULL;
+ int cpu = smp_processor_id();
+ int new_cpu = prev_cpu;
+ int want_affine = 0;
+ int sync = (wake_flags & WF_SYNC) && !(current->flags & PF_EXITING);
+ int target_cpu = -1;
+
+ trace_android_rvh_select_task_rq_fair(p, prev_cpu, sd_flag,
+ wake_flags, &target_cpu);
+ if (target_cpu >= 0)
+ return target_cpu;
+
+ if (sd_flag & SD_BALANCE_WAKE) {
+ record_wakee(p);
+
+ if (sched_energy_enabled()) {
+ new_cpu = find_energy_efficient_cpu(p, prev_cpu, sync);
+ if (new_cpu >= 0)
+ return new_cpu;
+ new_cpu = prev_cpu;
+ }
+
+ want_affine = !wake_wide(p) && cpumask_test_cpu(cpu, p->cpus_ptr);
+ }
+
+ rcu_read_lock();
+ for_each_domain(cpu, tmp) {
+ if (!(tmp->flags & SD_LOAD_BALANCE))
+ break;
+
+ /*
+ * If both 'cpu' and 'prev_cpu' are part of this domain,
+ * cpu is a valid SD_WAKE_AFFINE target.
+ */
+ if (want_affine && (tmp->flags & SD_WAKE_AFFINE) &&
+ cpumask_test_cpu(prev_cpu, sched_domain_span(tmp))) {
+ if (cpu != prev_cpu)
+ new_cpu = wake_affine(tmp, p, cpu, prev_cpu, sync);
+
+ sd = NULL; /* Prefer wake_affine over balance flags */
+ break;
+ }
+
+ if (tmp->flags & sd_flag)
+ sd = tmp;
+ else if (!want_affine)
+ break;
+ }
+
+ if (unlikely(sd)) {
+ /* Slow path */
+ new_cpu = find_idlest_cpu(sd, p, cpu, prev_cpu, sd_flag);
+ } else if (sd_flag & SD_BALANCE_WAKE) { /* XXX always ? */
+ /* Fast path */
+
+ new_cpu = select_idle_sibling(p, prev_cpu, new_cpu);
+
+ if (want_affine)
+ current->recent_used_cpu = cpu;
+ }
+ rcu_read_unlock();
+
+ return new_cpu;
+}
+
+static void detach_entity_cfs_rq(struct sched_entity *se);
+
+/*
+ * Called immediately before a task is migrated to a new CPU; task_cpu(p) and
+ * cfs_rq_of(p) references at time of call are still valid and identify the
+ * previous CPU. The caller guarantees p->pi_lock or task_rq(p)->lock is held.
+ */
+static void migrate_task_rq_fair(struct task_struct *p, int new_cpu)
+{
+ /*
+ * As blocked tasks retain absolute vruntime the migration needs to
+ * deal with this by subtracting the old and adding the new
+ * min_vruntime -- the latter is done by enqueue_entity() when placing
+ * the task on the new runqueue.
+ */
+ if (p->state == TASK_WAKING) {
+ struct sched_entity *se = &p->se;
+ struct cfs_rq *cfs_rq = cfs_rq_of(se);
+ u64 min_vruntime;
+
+#ifndef CONFIG_64BIT
+ u64 min_vruntime_copy;
+
+ do {
+ min_vruntime_copy = cfs_rq->min_vruntime_copy;
+ smp_rmb();
+ min_vruntime = cfs_rq->min_vruntime;
+ } while (min_vruntime != min_vruntime_copy);
+#else
+ min_vruntime = cfs_rq->min_vruntime;
+#endif
+
+ se->vruntime -= min_vruntime;
+ }
+
+ if (p->on_rq == TASK_ON_RQ_MIGRATING) {
+ /*
+ * In case of TASK_ON_RQ_MIGRATING we in fact hold the 'old'
+ * rq->lock and can modify state directly.
+ */
+ lockdep_assert_held(&task_rq(p)->lock);
+ detach_entity_cfs_rq(&p->se);
+
+ } else {
+ /*
+ * We are supposed to update the task to "current" time, then
+ * its up to date and ready to go to new CPU/cfs_rq. But we
+ * have difficulty in getting what current time is, so simply
+ * throw away the out-of-date time. This will result in the
+ * wakee task is less decayed, but giving the wakee more load
+ * sounds not bad.
+ */
+ remove_entity_load_avg(&p->se);
+ }
+
+ /* Tell new CPU we are migrated */
+ p->se.avg.last_update_time = 0;
+
+ update_scan_period(p, new_cpu);
+}
+
+static void task_dead_fair(struct task_struct *p)
+{
+ remove_entity_load_avg(&p->se);
+}
+
+static int
+balance_fair(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
+{
+ if (rq->nr_running)
+ return 1;
+
+ return newidle_balance(rq, rf) != 0;
+}
+#endif /* CONFIG_SMP */
+
+static unsigned long wakeup_gran(struct sched_entity *se)
+{
+ unsigned long gran = sysctl_sched_wakeup_granularity;
+
+ /*
+ * Since its curr running now, convert the gran from real-time
+ * to virtual-time in his units.
+ *
+ * By using 'se' instead of 'curr' we penalize light tasks, so
+ * they get preempted easier. That is, if 'se' < 'curr' then
+ * the resulting gran will be larger, therefore penalizing the
+ * lighter, if otoh 'se' > 'curr' then the resulting gran will
+ * be smaller, again penalizing the lighter task.
+ *
+ * This is especially important for buddies when the leftmost
+ * task is higher priority than the buddy.
+ */
+ return calc_delta_fair(gran, se);
+}
+
+/*
+ * Should 'se' preempt 'curr'.
+ *
+ * |s1
+ * |s2
+ * |s3
+ * g
+ * |<--->|c
+ *
+ * w(c, s1) = -1
+ * w(c, s2) = 0
+ * w(c, s3) = 1
+ *
+ */
+static int
+wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se)
+{
+ s64 gran, vdiff = curr->vruntime - se->vruntime;
+
+ if (vdiff <= 0)
+ return -1;
+
+ gran = wakeup_gran(se);
+ if (vdiff > gran)
+ return 1;
+
+ return 0;
+}
+
+static void set_last_buddy(struct sched_entity *se)
+{
+ if (entity_is_task(se) && unlikely(task_has_idle_policy(task_of(se))))
+ return;
+
+ for_each_sched_entity(se) {
+ if (SCHED_WARN_ON(!se->on_rq))
+ return;
+ cfs_rq_of(se)->last = se;
+ }
+}
+
+static void set_next_buddy(struct sched_entity *se)
+{
+ if (entity_is_task(se) && unlikely(task_has_idle_policy(task_of(se))))
+ return;
+
+ for_each_sched_entity(se) {
+ if (SCHED_WARN_ON(!se->on_rq))
+ return;
+ cfs_rq_of(se)->next = se;
+ }
+}
+
+static void set_skip_buddy(struct sched_entity *se)
+{
+ for_each_sched_entity(se)
+ cfs_rq_of(se)->skip = se;
+}
+
+/*
+ * Preempt the current task with a newly woken task if needed:
+ */
+static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_flags)
+{
+ struct task_struct *curr = rq->curr;
+ struct sched_entity *se = &curr->se, *pse = &p->se;
+ struct cfs_rq *cfs_rq = task_cfs_rq(curr);
+ int scale = cfs_rq->nr_running >= sched_nr_latency;
+ int next_buddy_marked = 0;
+
+ if (unlikely(se == pse))
+ return;
+
+ /*
+ * This is possible from callers such as attach_tasks(), in which we
+ * unconditionally check_prempt_curr() after an enqueue (which may have
+ * lead to a throttle). This both saves work and prevents false
+ * next-buddy nomination below.
+ */
+ if (unlikely(throttled_hierarchy(cfs_rq_of(pse))))
+ return;
+
+ if (sched_feat(NEXT_BUDDY) && scale && !(wake_flags & WF_FORK)) {
+ set_next_buddy(pse);
+ next_buddy_marked = 1;
+ }
+
+ /*
+ * We can come here with TIF_NEED_RESCHED already set from new task
+ * wake up path.
+ *
+ * Note: this also catches the edge-case of curr being in a throttled
+ * group (e.g. via set_curr_task), since update_curr() (in the
+ * enqueue of curr) will have resulted in resched being set. This
+ * prevents us from potentially nominating it as a false LAST_BUDDY
+ * below.
+ */
+ if (test_tsk_need_resched(curr))
+ return;
+
+ /* Idle tasks are by definition preempted by non-idle tasks. */
+ if (unlikely(task_has_idle_policy(curr)) &&
+ likely(!task_has_idle_policy(p)))
+ goto preempt;
+
+ /*
+ * Batch and idle tasks do not preempt non-idle tasks (their preemption
+ * is driven by the tick):
+ */
+ if (unlikely(p->policy != SCHED_NORMAL) || !sched_feat(WAKEUP_PREEMPTION))
+ return;
+
+ find_matching_se(&se, &pse);
+ update_curr(cfs_rq_of(se));
+ BUG_ON(!pse);
+ if (wakeup_preempt_entity(se, pse) == 1) {
+ /*
+ * Bias pick_next to pick the sched entity that is
+ * triggering this preemption.
+ */
+ if (!next_buddy_marked)
+ set_next_buddy(pse);
+ goto preempt;
+ }
+
+ return;
+
+preempt:
+ resched_curr(rq);
+ /*
+ * Only set the backward buddy when the current task is still
+ * on the rq. This can happen when a wakeup gets interleaved
+ * with schedule on the ->pre_schedule() or idle_balance()
+ * point, either of which can * drop the rq lock.
+ *
+ * Also, during early boot the idle thread is in the fair class,
+ * for obvious reasons its a bad idea to schedule back to it.
+ */
+ if (unlikely(!se->on_rq || curr == rq->idle))
+ return;
+
+ if (sched_feat(LAST_BUDDY) && scale && entity_is_task(se))
+ set_last_buddy(se);
+}
+
+static struct task_struct *
+pick_next_task_fair(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
+{
+ struct cfs_rq *cfs_rq = &rq->cfs;
+ struct sched_entity *se;
+ struct task_struct *p;
+ int new_tasks;
+
+again:
+ if (!sched_fair_runnable(rq))
+ goto idle;
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+ if (!prev || prev->sched_class != &fair_sched_class)
+ goto simple;
+
+ /*
+ * Because of the set_next_buddy() in dequeue_task_fair() it is rather
+ * likely that a next task is from the same cgroup as the current.
+ *
+ * Therefore attempt to avoid putting and setting the entire cgroup
+ * hierarchy, only change the part that actually changes.
+ */
+
+ do {
+ struct sched_entity *curr = cfs_rq->curr;
+
+ /*
+ * Since we got here without doing put_prev_entity() we also
+ * have to consider cfs_rq->curr. If it is still a runnable
+ * entity, update_curr() will update its vruntime, otherwise
+ * forget we've ever seen it.
+ */
+ if (curr) {
+ if (curr->on_rq)
+ update_curr(cfs_rq);
+ else
+ curr = NULL;
+
+ /*
+ * This call to check_cfs_rq_runtime() will do the
+ * throttle and dequeue its entity in the parent(s).
+ * Therefore the nr_running test will indeed
+ * be correct.
+ */
+ if (unlikely(check_cfs_rq_runtime(cfs_rq))) {
+ cfs_rq = &rq->cfs;
+
+ if (!cfs_rq->nr_running)
+ goto idle;
+
+ goto simple;
+ }
+ }
+
+ se = pick_next_entity(cfs_rq, curr);
+ cfs_rq = group_cfs_rq(se);
+ } while (cfs_rq);
+
+ p = task_of(se);
+
+ /*
+ * Since we haven't yet done put_prev_entity and if the selected task
+ * is a different task than we started out with, try and touch the
+ * least amount of cfs_rqs.
+ */
+ if (prev != p) {
+ struct sched_entity *pse = &prev->se;
+
+ while (!(cfs_rq = is_same_group(se, pse))) {
+ int se_depth = se->depth;
+ int pse_depth = pse->depth;
+
+ if (se_depth <= pse_depth) {
+ put_prev_entity(cfs_rq_of(pse), pse);
+ pse = parent_entity(pse);
+ }
+ if (se_depth >= pse_depth) {
+ set_next_entity(cfs_rq_of(se), se);
+ se = parent_entity(se);
+ }
+ }
+
+ put_prev_entity(cfs_rq, pse);
+ set_next_entity(cfs_rq, se);
+ }
+
+ goto done;
+simple:
+#endif
+ if (prev)
+ put_prev_task(rq, prev);
+
+ do {
+ se = pick_next_entity(cfs_rq, NULL);
+ set_next_entity(cfs_rq, se);
+ cfs_rq = group_cfs_rq(se);
+ } while (cfs_rq);
+
+ p = task_of(se);
+
+done: __maybe_unused;
+#ifdef CONFIG_SMP
+ /*
+ * Move the next running task to the front of
+ * the list, so our cfs_tasks list becomes MRU
+ * one.
+ */
+ list_move(&p->se.group_node, &rq->cfs_tasks);
+#endif
+
+ if (hrtick_enabled(rq))
+ hrtick_start_fair(rq, p);
+
+ update_misfit_status(p, rq);
+
+ return p;
+
+idle:
+ if (!rf)
+ return NULL;
+
+ new_tasks = newidle_balance(rq, rf);
+
+ /*
+ * Because newidle_balance() releases (and re-acquires) rq->lock, it is
+ * possible for any higher priority task to appear. In that case we
+ * must re-start the pick_next_entity() loop.
+ */
+ if (new_tasks < 0)
+ return RETRY_TASK;
+
+ if (new_tasks > 0)
+ goto again;
+
+ /*
+ * rq is about to be idle, check if we need to update the
+ * lost_idle_time of clock_pelt
+ */
+ update_idle_rq_clock_pelt(rq);
+
+ return NULL;
+}
+
+/*
+ * Account for a descheduled task:
+ */
+static void put_prev_task_fair(struct rq *rq, struct task_struct *prev)
+{
+ struct sched_entity *se = &prev->se;
+ struct cfs_rq *cfs_rq;
+
+ for_each_sched_entity(se) {
+ cfs_rq = cfs_rq_of(se);
+ put_prev_entity(cfs_rq, se);
+ }
+}
+
+/*
+ * sched_yield() is very simple
+ *
+ * The magic of dealing with the ->skip buddy is in pick_next_entity.
+ */
+static void yield_task_fair(struct rq *rq)
+{
+ struct task_struct *curr = rq->curr;
+ struct cfs_rq *cfs_rq = task_cfs_rq(curr);
+ struct sched_entity *se = &curr->se;
+
+ /*
+ * Are we the only task in the tree?
+ */
+ if (unlikely(rq->nr_running == 1))
+ return;
+
+ clear_buddies(cfs_rq, se);
+
+ if (curr->policy != SCHED_BATCH) {
+ update_rq_clock(rq);
+ /*
+ * Update run-time statistics of the 'current'.
+ */
+ update_curr(cfs_rq);
+ /*
+ * Tell update_rq_clock() that we've just updated,
+ * so we don't do microscopic update in schedule()
+ * and double the fastpath cost.
+ */
+ rq_clock_skip_update(rq);
+ }
+
+ set_skip_buddy(se);
+}
+
+static bool yield_to_task_fair(struct rq *rq, struct task_struct *p, bool preempt)
+{
+ struct sched_entity *se = &p->se;
+
+ /* throttled hierarchies are not runnable */
+ if (!se->on_rq || throttled_hierarchy(cfs_rq_of(se)))
+ return false;
+
+ /* Tell the scheduler that we'd really like pse to run next. */
+ set_next_buddy(se);
+
+ yield_task_fair(rq);
+
+ return true;
+}
+
+#ifdef CONFIG_SMP
+/**************************************************
+ * Fair scheduling class load-balancing methods.
+ *
+ * BASICS
+ *
+ * The purpose of load-balancing is to achieve the same basic fairness the
+ * per-CPU scheduler provides, namely provide a proportional amount of compute
+ * time to each task. This is expressed in the following equation:
+ *
+ * W_i,n/P_i == W_j,n/P_j for all i,j (1)
+ *
+ * Where W_i,n is the n-th weight average for CPU i. The instantaneous weight
+ * W_i,0 is defined as:
+ *
+ * W_i,0 = \Sum_j w_i,j (2)
+ *
+ * Where w_i,j is the weight of the j-th runnable task on CPU i. This weight
+ * is derived from the nice value as per sched_prio_to_weight[].
+ *
+ * The weight average is an exponential decay average of the instantaneous
+ * weight:
+ *
+ * W'_i,n = (2^n - 1) / 2^n * W_i,n + 1 / 2^n * W_i,0 (3)
+ *
+ * C_i is the compute capacity of CPU i, typically it is the
+ * fraction of 'recent' time available for SCHED_OTHER task execution. But it
+ * can also include other factors [XXX].
+ *
+ * To achieve this balance we define a measure of imbalance which follows
+ * directly from (1):
+ *
+ * imb_i,j = max{ avg(W/C), W_i/C_i } - min{ avg(W/C), W_j/C_j } (4)
+ *
+ * We them move tasks around to minimize the imbalance. In the continuous
+ * function space it is obvious this converges, in the discrete case we get
+ * a few fun cases generally called infeasible weight scenarios.
+ *
+ * [XXX expand on:
+ * - infeasible weights;
+ * - local vs global optima in the discrete case. ]
+ *
+ *
+ * SCHED DOMAINS
+ *
+ * In order to solve the imbalance equation (4), and avoid the obvious O(n^2)
+ * for all i,j solution, we create a tree of CPUs that follows the hardware
+ * topology where each level pairs two lower groups (or better). This results
+ * in O(log n) layers. Furthermore we reduce the number of CPUs going up the
+ * tree to only the first of the previous level and we decrease the frequency
+ * of load-balance at each level inv. proportional to the number of CPUs in
+ * the groups.
+ *
+ * This yields:
+ *
+ * log_2 n 1 n
+ * \Sum { --- * --- * 2^i } = O(n) (5)
+ * i = 0 2^i 2^i
+ * `- size of each group
+ * | | `- number of CPUs doing load-balance
+ * | `- freq
+ * `- sum over all levels
+ *
+ * Coupled with a limit on how many tasks we can migrate every balance pass,
+ * this makes (5) the runtime complexity of the balancer.
+ *
+ * An important property here is that each CPU is still (indirectly) connected
+ * to every other CPU in at most O(log n) steps:
+ *
+ * The adjacency matrix of the resulting graph is given by:
+ *
+ * log_2 n
+ * A_i,j = \Union (i % 2^k == 0) && i / 2^(k+1) == j / 2^(k+1) (6)
+ * k = 0
+ *
+ * And you'll find that:
+ *
+ * A^(log_2 n)_i,j != 0 for all i,j (7)
+ *
+ * Showing there's indeed a path between every CPU in at most O(log n) steps.
+ * The task movement gives a factor of O(m), giving a convergence complexity
+ * of:
+ *
+ * O(nm log n), n := nr_cpus, m := nr_tasks (8)
+ *
+ *
+ * WORK CONSERVING
+ *
+ * In order to avoid CPUs going idle while there's still work to do, new idle
+ * balancing is more aggressive and has the newly idle CPU iterate up the domain
+ * tree itself instead of relying on other CPUs to bring it work.
+ *
+ * This adds some complexity to both (5) and (8) but it reduces the total idle
+ * time.
+ *
+ * [XXX more?]
+ *
+ *
+ * CGROUPS
+ *
+ * Cgroups make a horror show out of (2), instead of a simple sum we get:
+ *
+ * s_k,i
+ * W_i,0 = \Sum_j \Prod_k w_k * ----- (9)
+ * S_k
+ *
+ * Where
+ *
+ * s_k,i = \Sum_j w_i,j,k and S_k = \Sum_i s_k,i (10)
+ *
+ * w_i,j,k is the weight of the j-th runnable task in the k-th cgroup on CPU i.
+ *
+ * The big problem is S_k, its a global sum needed to compute a local (W_i)
+ * property.
+ *
+ * [XXX write more on how we solve this.. _after_ merging pjt's patches that
+ * rewrite all of this once again.]
+ */
+
+static unsigned long __read_mostly max_load_balance_interval = HZ/10;
+
+enum fbq_type { regular, remote, all };
+
+enum group_type {
+ group_other = 0,
+ group_misfit_task,
+ group_imbalanced,
+ group_overloaded,
+};
+
+#define LBF_ALL_PINNED 0x01
+#define LBF_NEED_BREAK 0x02
+#define LBF_DST_PINNED 0x04
+#define LBF_SOME_PINNED 0x08
+#define LBF_NOHZ_STATS 0x10
+#define LBF_NOHZ_AGAIN 0x20
+
+struct lb_env {
+ struct sched_domain *sd;
+
+ struct rq *src_rq;
+ int src_cpu;
+
+ int dst_cpu;
+ struct rq *dst_rq;
+
+ struct cpumask *dst_grpmask;
+ int new_dst_cpu;
+ enum cpu_idle_type idle;
+ long imbalance;
+ unsigned int src_grp_nr_running;
+ /* The set of CPUs under consideration for load-balancing */
+ struct cpumask *cpus;
+
+ unsigned int flags;
+
+ unsigned int loop;
+ unsigned int loop_break;
+ unsigned int loop_max;
+
+ enum fbq_type fbq_type;
+ enum group_type src_grp_type;
+ struct list_head tasks;
+};
+
+/*
+ * Is this task likely cache-hot:
+ */
+static int task_hot(struct task_struct *p, struct lb_env *env)
+{
+ s64 delta;
+
+ lockdep_assert_held(&env->src_rq->lock);
+
+ if (p->sched_class != &fair_sched_class)
+ return 0;
+
+ if (unlikely(task_has_idle_policy(p)))
+ return 0;
+
+ /*
+ * Buddy candidates are cache hot:
+ */
+ if (sched_feat(CACHE_HOT_BUDDY) && env->dst_rq->nr_running &&
+ (&p->se == cfs_rq_of(&p->se)->next ||
+ &p->se == cfs_rq_of(&p->se)->last))
+ return 1;
+
+ if (sysctl_sched_migration_cost == -1)
+ return 1;
+ if (sysctl_sched_migration_cost == 0)
+ return 0;
+
+ delta = rq_clock_task(env->src_rq) - p->se.exec_start;
+
+ return delta < (s64)sysctl_sched_migration_cost;
+}
+
+#ifdef CONFIG_NUMA_BALANCING
+/*
+ * Returns 1, if task migration degrades locality
+ * Returns 0, if task migration improves locality i.e migration preferred.
+ * Returns -1, if task migration is not affected by locality.
+ */
+static int migrate_degrades_locality(struct task_struct *p, struct lb_env *env)
+{
+ struct numa_group *numa_group = rcu_dereference(p->numa_group);
+ unsigned long src_weight, dst_weight;
+ int src_nid, dst_nid, dist;
+
+ if (!static_branch_likely(&sched_numa_balancing))
+ return -1;
+
+ if (!p->numa_faults || !(env->sd->flags & SD_NUMA))
+ return -1;
+
+ src_nid = cpu_to_node(env->src_cpu);
+ dst_nid = cpu_to_node(env->dst_cpu);
+
+ if (src_nid == dst_nid)
+ return -1;
+
+ /* Migrating away from the preferred node is always bad. */
+ if (src_nid == p->numa_preferred_nid) {
+ if (env->src_rq->nr_running > env->src_rq->nr_preferred_running)
+ return 1;
+ else
+ return -1;
+ }
+
+ /* Encourage migration to the preferred node. */
+ if (dst_nid == p->numa_preferred_nid)
+ return 0;
+
+ /* Leaving a core idle is often worse than degrading locality. */
+ if (env->idle == CPU_IDLE)
+ return -1;
+
+ dist = node_distance(src_nid, dst_nid);
+ if (numa_group) {
+ src_weight = group_weight(p, src_nid, dist);
+ dst_weight = group_weight(p, dst_nid, dist);
+ } else {
+ src_weight = task_weight(p, src_nid, dist);
+ dst_weight = task_weight(p, dst_nid, dist);
+ }
+
+ return dst_weight < src_weight;
+}
+
+#else
+static inline int migrate_degrades_locality(struct task_struct *p,
+ struct lb_env *env)
+{
+ return -1;
+}
+#endif
+
+/*
+ * can_migrate_task - may task p from runqueue rq be migrated to this_cpu?
+ */
+static
+int can_migrate_task(struct task_struct *p, struct lb_env *env)
+{
+ int tsk_cache_hot;
+ int can_migrate = 1;
+
+ lockdep_assert_held(&env->src_rq->lock);
+
+ trace_android_rvh_can_migrate_task(p, env->dst_cpu, &can_migrate);
+ if (!can_migrate)
+ return 0;
+
+ /*
+ * We do not migrate tasks that are:
+ * 1) throttled_lb_pair, or
+ * 2) cannot be migrated to this CPU due to cpus_ptr, or
+ * 3) running (obviously), or
+ * 4) are cache-hot on their current CPU.
+ */
+ if (throttled_lb_pair(task_group(p), env->src_cpu, env->dst_cpu))
+ return 0;
+
+ /* Disregard pcpu kthreads; they are where they need to be. */
+ if (kthread_is_per_cpu(p))
+ return 0;
+
+ if (!cpumask_test_cpu(env->dst_cpu, p->cpus_ptr)) {
+ int cpu;
+
+ schedstat_inc(p->se.statistics.nr_failed_migrations_affine);
+
+ env->flags |= LBF_SOME_PINNED;
+
+ /*
+ * Remember if this task can be migrated to any other CPU in
+ * our sched_group. We may want to revisit it if we couldn't
+ * meet load balance goals by pulling other tasks on src_cpu.
+ *
+ * Avoid computing new_dst_cpu for NEWLY_IDLE or if we have
+ * already computed one in current iteration.
+ */
+ if (env->idle == CPU_NEWLY_IDLE || (env->flags & LBF_DST_PINNED))
+ return 0;
+
+ /* Prevent to re-select dst_cpu via env's CPUs: */
+ for_each_cpu_and(cpu, env->dst_grpmask, env->cpus) {
+ if (cpumask_test_cpu(cpu, p->cpus_ptr)) {
+ env->flags |= LBF_DST_PINNED;
+ env->new_dst_cpu = cpu;
+ break;
+ }
+ }
+
+ return 0;
+ }
+
+ /* Record that we found atleast one task that could run on dst_cpu */
+ env->flags &= ~LBF_ALL_PINNED;
+
+ if (task_running(env->src_rq, p)) {
+ schedstat_inc(p->se.statistics.nr_failed_migrations_running);
+ return 0;
+ }
+
+ /*
+ * Aggressive migration if:
+ * 1) destination numa is preferred
+ * 2) task is cache cold, or
+ * 3) too many balance attempts have failed.
+ */
+ tsk_cache_hot = migrate_degrades_locality(p, env);
+ if (tsk_cache_hot == -1)
+ tsk_cache_hot = task_hot(p, env);
+
+ if (tsk_cache_hot <= 0 ||
+ env->sd->nr_balance_failed > env->sd->cache_nice_tries) {
+ if (tsk_cache_hot == 1) {
+ schedstat_inc(env->sd->lb_hot_gained[env->idle]);
+ schedstat_inc(p->se.statistics.nr_forced_migrations);
+ }
+ return 1;
+ }
+
+ schedstat_inc(p->se.statistics.nr_failed_migrations_hot);
+ return 0;
+}
+
+/*
+ * detach_task() -- detach the task for the migration specified in env
+ */
+static void detach_task(struct task_struct *p, struct lb_env *env)
+{
+ lockdep_assert_held(&env->src_rq->lock);
+
+ deactivate_task(env->src_rq, p, DEQUEUE_NOCLOCK);
+ set_task_cpu(p, env->dst_cpu);
+}
+
+/*
+ * detach_one_task() -- tries to dequeue exactly one task from env->src_rq, as
+ * part of active balancing operations within "domain".
+ *
+ * Returns a task if successful and NULL otherwise.
+ */
+static struct task_struct *detach_one_task(struct lb_env *env)
+{
+ struct task_struct *p;
+
+ lockdep_assert_held(&env->src_rq->lock);
+
+ list_for_each_entry_reverse(p,
+ &env->src_rq->cfs_tasks, se.group_node) {
+ if (!can_migrate_task(p, env))
+ continue;
+
+ detach_task(p, env);
+
+ /*
+ * Right now, this is only the second place where
+ * lb_gained[env->idle] is updated (other is detach_tasks)
+ * so we can safely collect stats here rather than
+ * inside detach_tasks().
+ */
+ schedstat_inc(env->sd->lb_gained[env->idle]);
+ return p;
+ }
+ return NULL;
+}
+
+static const unsigned int sched_nr_migrate_break = 32;
+
+/*
+ * detach_tasks() -- tries to detach up to imbalance runnable load from
+ * busiest_rq, as part of a balancing operation within domain "sd".
+ *
+ * Returns number of detached tasks if successful and 0 otherwise.
+ */
+static int detach_tasks(struct lb_env *env)
+{
+ struct list_head *tasks = &env->src_rq->cfs_tasks;
+ struct task_struct *p;
+ unsigned long load;
+ int detached = 0;
+
+ lockdep_assert_held(&env->src_rq->lock);
+
+ if (env->imbalance <= 0)
+ return 0;
+
+ while (!list_empty(tasks)) {
+ /*
+ * We don't want to steal all, otherwise we may be treated likewise,
+ * which could at worst lead to a livelock crash.
+ */
+ if (env->idle != CPU_NOT_IDLE && env->src_rq->nr_running <= 1)
+ break;
+
+ p = list_last_entry(tasks, struct task_struct, se.group_node);
+
+ env->loop++;
+ /* We've more or less seen every task there is, call it quits */
+ if (env->loop > env->loop_max)
+ break;
+
+ /* take a breather every nr_migrate tasks */
+ if (env->loop > env->loop_break) {
+ env->loop_break += sched_nr_migrate_break;
+ env->flags |= LBF_NEED_BREAK;
+ break;
+ }
+
+ if (!can_migrate_task(p, env))
+ goto next;
+
+ /*
+ * Depending of the number of CPUs and tasks and the
+ * cgroup hierarchy, task_h_load() can return a null
+ * value. Make sure that env->imbalance decreases
+ * otherwise detach_tasks() will stop only after
+ * detaching up to loop_max tasks.
+ */
+ load = max_t(unsigned long, task_h_load(p), 1);
+
+
+ if (sched_feat(LB_MIN) && load < 16 && !env->sd->nr_balance_failed)
+ goto next;
+
+ if ((load / 2) > env->imbalance)
+ goto next;
+
+ detach_task(p, env);
+ list_add(&p->se.group_node, &env->tasks);
+
+ detached++;
+ env->imbalance -= load;
+
+#ifdef CONFIG_PREEMPTION
+ /*
+ * NEWIDLE balancing is a source of latency, so preemptible
+ * kernels will stop after the first task is detached to minimize
+ * the critical section.
+ */
+ if (env->idle == CPU_NEWLY_IDLE)
+ break;
+#endif
+
+ /*
+ * We only want to steal up to the prescribed amount of
+ * runnable load.
+ */
+ if (env->imbalance <= 0)
+ break;
+
+ continue;
+next:
+ list_move(&p->se.group_node, tasks);
+ }
+
+ /*
+ * Right now, this is one of only two places we collect this stat
+ * so we can safely collect detach_one_task() stats here rather
+ * than inside detach_one_task().
+ */
+ schedstat_add(env->sd->lb_gained[env->idle], detached);
+
+ return detached;
+}
+
+/*
+ * attach_task() -- attach the task detached by detach_task() to its new rq.
+ */
+static void attach_task(struct rq *rq, struct task_struct *p)
+{
+ lockdep_assert_held(&rq->lock);
+
+ BUG_ON(task_rq(p) != rq);
+ activate_task(rq, p, ENQUEUE_NOCLOCK);
+ check_preempt_curr(rq, p, 0);
+}
+
+/*
+ * attach_one_task() -- attaches the task returned from detach_one_task() to
+ * its new rq.
+ */
+static void attach_one_task(struct rq *rq, struct task_struct *p)
+{
+ struct rq_flags rf;
+
+ rq_lock(rq, &rf);
+ update_rq_clock(rq);
+ attach_task(rq, p);
+ rq_unlock(rq, &rf);
+}
+
+/*
+ * attach_tasks() -- attaches all tasks detached by detach_tasks() to their
+ * new rq.
+ */
+static void attach_tasks(struct lb_env *env)
+{
+ struct list_head *tasks = &env->tasks;
+ struct task_struct *p;
+ struct rq_flags rf;
+
+ rq_lock(env->dst_rq, &rf);
+ update_rq_clock(env->dst_rq);
+
+ while (!list_empty(tasks)) {
+ p = list_first_entry(tasks, struct task_struct, se.group_node);
+ list_del_init(&p->se.group_node);
+
+ attach_task(env->dst_rq, p);
+ }
+
+ rq_unlock(env->dst_rq, &rf);
+}
+
+#ifdef CONFIG_NO_HZ_COMMON
+static inline bool cfs_rq_has_blocked(struct cfs_rq *cfs_rq)
+{
+ if (cfs_rq->avg.load_avg)
+ return true;
+
+ if (cfs_rq->avg.util_avg)
+ return true;
+
+ return false;
+}
+
+static inline bool others_have_blocked(struct rq *rq)
+{
+ if (READ_ONCE(rq->avg_rt.util_avg))
+ return true;
+
+ if (READ_ONCE(rq->avg_dl.util_avg))
+ return true;
+
+#ifdef CONFIG_HAVE_SCHED_AVG_IRQ
+ if (READ_ONCE(rq->avg_irq.util_avg))
+ return true;
+#endif
+
+ return false;
+}
+
+static inline void update_blocked_load_status(struct rq *rq, bool has_blocked)
+{
+ rq->last_blocked_load_update_tick = jiffies;
+
+ if (!has_blocked)
+ rq->has_blocked_load = 0;
+}
+#else
+static inline bool cfs_rq_has_blocked(struct cfs_rq *cfs_rq) { return false; }
+static inline bool others_have_blocked(struct rq *rq) { return false; }
+static inline void update_blocked_load_status(struct rq *rq, bool has_blocked) {}
+#endif
+
+static bool __update_blocked_others(struct rq *rq, bool *done)
+{
+ const struct sched_class *curr_class;
+ u64 now = rq_clock_pelt(rq);
+ bool decayed;
+
+ /*
+ * update_load_avg() can call cpufreq_update_util(). Make sure that RT,
+ * DL and IRQ signals have been updated before updating CFS.
+ */
+ curr_class = rq->curr->sched_class;
+
+ decayed = update_rt_rq_load_avg(now, rq, curr_class == &rt_sched_class) |
+ update_dl_rq_load_avg(now, rq, curr_class == &dl_sched_class) |
+ update_irq_load_avg(rq, 0);
+
+ if (others_have_blocked(rq))
+ *done = false;
+
+ return decayed;
+}
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+
+static inline bool cfs_rq_is_decayed(struct cfs_rq *cfs_rq)
+{
+ if (cfs_rq->load.weight)
+ return false;
+
+ if (cfs_rq->avg.load_sum)
+ return false;
+
+ if (cfs_rq->avg.util_sum)
+ return false;
+
+ if (cfs_rq->avg.runnable_load_sum)
+ return false;
+
+ return true;
+}
+
+static bool __update_blocked_fair(struct rq *rq, bool *done)
+{
+ struct cfs_rq *cfs_rq, *pos;
+ bool decayed = false;
+ int cpu = cpu_of(rq);
+
+ /*
+ * Iterates the task_group tree in a bottom up fashion, see
+ * list_add_leaf_cfs_rq() for details.
+ */
+ for_each_leaf_cfs_rq_safe(rq, cfs_rq, pos) {
+ struct sched_entity *se;
+
+ if (update_cfs_rq_load_avg(cfs_rq_clock_pelt(cfs_rq), cfs_rq)) {
+ update_tg_load_avg(cfs_rq, 0);
+
+ if (cfs_rq == &rq->cfs)
+ decayed = true;
+ }
+
+ /* Propagate pending load changes to the parent, if any: */
+ se = cfs_rq->tg->se[cpu];
+ if (se && !skip_blocked_update(se))
+ update_load_avg(cfs_rq_of(se), se, UPDATE_TG);
+
+ /*
+ * There can be a lot of idle CPU cgroups. Don't let fully
+ * decayed cfs_rqs linger on the list.
+ */
+ if (cfs_rq_is_decayed(cfs_rq))
+ list_del_leaf_cfs_rq(cfs_rq);
+
+ /* Don't need periodic decay once load/util_avg are null */
+ if (cfs_rq_has_blocked(cfs_rq))
+ *done = false;
+ }
+
+ return decayed;
+}
+
+/*
+ * Compute the hierarchical load factor for cfs_rq and all its ascendants.
+ * This needs to be done in a top-down fashion because the load of a child
+ * group is a fraction of its parents load.
+ */
+static void update_cfs_rq_h_load(struct cfs_rq *cfs_rq)
+{
+ struct rq *rq = rq_of(cfs_rq);
+ struct sched_entity *se = cfs_rq->tg->se[cpu_of(rq)];
+ unsigned long now = jiffies;
+ unsigned long load;
+
+ if (cfs_rq->last_h_load_update == now)
+ return;
+
+ WRITE_ONCE(cfs_rq->h_load_next, NULL);
+ for_each_sched_entity(se) {
+ cfs_rq = cfs_rq_of(se);
+ WRITE_ONCE(cfs_rq->h_load_next, se);
+ if (cfs_rq->last_h_load_update == now)
+ break;
+ }
+
+ if (!se) {
+ cfs_rq->h_load = cfs_rq_load_avg(cfs_rq);
+ cfs_rq->last_h_load_update = now;
+ }
+
+ while ((se = READ_ONCE(cfs_rq->h_load_next)) != NULL) {
+ load = cfs_rq->h_load;
+ load = div64_ul(load * se->avg.load_avg,
+ cfs_rq_load_avg(cfs_rq) + 1);
+ cfs_rq = group_cfs_rq(se);
+ cfs_rq->h_load = load;
+ cfs_rq->last_h_load_update = now;
+ }
+}
+
+static unsigned long task_h_load(struct task_struct *p)
+{
+ struct cfs_rq *cfs_rq = task_cfs_rq(p);
+
+ update_cfs_rq_h_load(cfs_rq);
+ return div64_ul(p->se.avg.load_avg * cfs_rq->h_load,
+ cfs_rq_load_avg(cfs_rq) + 1);
+}
+#else
+static bool __update_blocked_fair(struct rq *rq, bool *done)
+{
+ struct cfs_rq *cfs_rq = &rq->cfs;
+ bool decayed;
+
+ decayed = update_cfs_rq_load_avg(cfs_rq_clock_pelt(cfs_rq), cfs_rq);
+ if (cfs_rq_has_blocked(cfs_rq))
+ *done = false;
+
+ return decayed;
+}
+
+static unsigned long task_h_load(struct task_struct *p)
+{
+ return p->se.avg.load_avg;
+}
+#endif
+
+static void update_blocked_averages(int cpu)
+{
+ bool decayed = false, done = true;
+ struct rq *rq = cpu_rq(cpu);
+ struct rq_flags rf;
+
+ rq_lock_irqsave(rq, &rf);
+ update_rq_clock(rq);
+
+ decayed |= __update_blocked_others(rq, &done);
+ decayed |= __update_blocked_fair(rq, &done);
+
+ update_blocked_load_status(rq, !done);
+ if (decayed)
+ cpufreq_update_util(rq, 0);
+ rq_unlock_irqrestore(rq, &rf);
+}
+
+/********** Helpers for find_busiest_group ************************/
+
+/*
+ * sg_lb_stats - stats of a sched_group required for load_balancing
+ */
+struct sg_lb_stats {
+ unsigned long avg_load; /*Avg load across the CPUs of the group */
+ unsigned long group_load; /* Total load over the CPUs of the group */
+ unsigned long load_per_task;
+ unsigned long group_capacity;
+ unsigned long group_util; /* Total utilization of the group */
+ unsigned int sum_nr_running; /* Nr tasks running in the group */
+ unsigned int idle_cpus;
+ unsigned int group_weight;
+ enum group_type group_type;
+ int group_no_capacity;
+ unsigned long group_misfit_task_load; /* A CPU has a task too big for its capacity */
+#ifdef CONFIG_NUMA_BALANCING
+ unsigned int nr_numa_running;
+ unsigned int nr_preferred_running;
+#endif
+};
+
+/*
+ * sd_lb_stats - Structure to store the statistics of a sched_domain
+ * during load balancing.
+ */
+struct sd_lb_stats {
+ struct sched_group *busiest; /* Busiest group in this sd */
+ struct sched_group *local; /* Local group in this sd */
+ unsigned long total_running;
+ unsigned long total_load; /* Total load of all groups in sd */
+ unsigned long total_capacity; /* Total capacity of all groups in sd */
+ unsigned long avg_load; /* Average load across all groups in sd */
+
+ struct sg_lb_stats busiest_stat;/* Statistics of the busiest group */
+ struct sg_lb_stats local_stat; /* Statistics of the local group */
+};
+
+static inline void init_sd_lb_stats(struct sd_lb_stats *sds)
+{
+ /*
+ * Skimp on the clearing to avoid duplicate work. We can avoid clearing
+ * local_stat because update_sg_lb_stats() does a full clear/assignment.
+ * We must however clear busiest_stat::avg_load because
+ * update_sd_pick_busiest() reads this before assignment.
+ */
+ *sds = (struct sd_lb_stats){
+ .busiest = NULL,
+ .local = NULL,
+ .total_running = 0UL,
+ .total_load = 0UL,
+ .total_capacity = 0UL,
+ .busiest_stat = {
+ .avg_load = 0UL,
+ .sum_nr_running = 0,
+ .group_type = group_other,
+ },
+ };
+}
+
+static unsigned long scale_rt_capacity(int cpu, unsigned long max)
+{
+ struct rq *rq = cpu_rq(cpu);
+ unsigned long used, free;
+ unsigned long irq;
+
+ irq = cpu_util_irq(rq);
+
+ if (unlikely(irq >= max))
+ return 1;
+
+ used = READ_ONCE(rq->avg_rt.util_avg);
+ used += READ_ONCE(rq->avg_dl.util_avg);
+
+ if (unlikely(used >= max))
+ return 1;
+
+ free = max - used;
+
+ return scale_irq_capacity(free, irq, max);
+}
+
+void init_max_cpu_capacity(struct max_cpu_capacity *mcc) {
+ raw_spin_lock_init(&mcc->lock);
+ mcc->val = 0;
+ mcc->cpu = -1;
+}
+
+static void update_cpu_capacity(struct sched_domain *sd, int cpu)
+{
+ unsigned long capacity = arch_scale_cpu_capacity(cpu);
+ struct sched_group *sdg = sd->groups;
+ struct max_cpu_capacity *mcc;
+ unsigned long max_capacity;
+ int max_cap_cpu;
+ unsigned long flags;
+
+ cpu_rq(cpu)->cpu_capacity_orig = capacity;
+
+ capacity *= arch_scale_max_freq_capacity(sd, cpu);
+ capacity >>= SCHED_CAPACITY_SHIFT;
+
+ mcc = &cpu_rq(cpu)->rd->max_cpu_capacity;
+
+ raw_spin_lock_irqsave(&mcc->lock, flags);
+ max_capacity = mcc->val;
+ max_cap_cpu = mcc->cpu;
+
+ if ((max_capacity > capacity && max_cap_cpu == cpu) ||
+ (max_capacity < capacity)) {
+ mcc->val = capacity;
+ mcc->cpu = cpu;
+#ifdef CONFIG_SCHED_DEBUG
+ raw_spin_unlock_irqrestore(&mcc->lock, flags);
+ printk_deferred(KERN_INFO "CPU%d: update max cpu_capacity %lu\n",
+ cpu, capacity);
+ goto skip_unlock;
+#endif
+ }
+ raw_spin_unlock_irqrestore(&mcc->lock, flags);
+
+skip_unlock: __attribute__ ((unused));
+ capacity = scale_rt_capacity(cpu, capacity);
+
+ if (!capacity)
+ capacity = 1;
+
+ cpu_rq(cpu)->cpu_capacity = capacity;
+ sdg->sgc->capacity = capacity;
+ sdg->sgc->min_capacity = capacity;
+ sdg->sgc->max_capacity = capacity;
+}
+
+void update_group_capacity(struct sched_domain *sd, int cpu)
+{
+ struct sched_domain *child = sd->child;
+ struct sched_group *group, *sdg = sd->groups;
+ unsigned long capacity, min_capacity, max_capacity;
+ unsigned long interval;
+
+ interval = msecs_to_jiffies(sd->balance_interval);
+ interval = clamp(interval, 1UL, max_load_balance_interval);
+ sdg->sgc->next_update = jiffies + interval;
+
+ if (!child) {
+ update_cpu_capacity(sd, cpu);
+ return;
+ }
+
+ capacity = 0;
+ min_capacity = ULONG_MAX;
+ max_capacity = 0;
+
+ if (child->flags & SD_OVERLAP) {
+ /*
+ * SD_OVERLAP domains cannot assume that child groups
+ * span the current group.
+ */
+
+ for_each_cpu(cpu, sched_group_span(sdg)) {
+ struct sched_group_capacity *sgc;
+ struct rq *rq = cpu_rq(cpu);
+
+ /*
+ * build_sched_domains() -> init_sched_groups_capacity()
+ * gets here before we've attached the domains to the
+ * runqueues.
+ *
+ * Use capacity_of(), which is set irrespective of domains
+ * in update_cpu_capacity().
+ *
+ * This avoids capacity from being 0 and
+ * causing divide-by-zero issues on boot.
+ */
+ if (unlikely(!rq->sd)) {
+ capacity += capacity_of(cpu);
+ } else {
+ sgc = rq->sd->groups->sgc;
+ capacity += sgc->capacity;
+ }
+
+ min_capacity = min(capacity, min_capacity);
+ max_capacity = max(capacity, max_capacity);
+ }
+ } else {
+ /*
+ * !SD_OVERLAP domains can assume that child groups
+ * span the current group.
+ */
+
+ group = child->groups;
+ do {
+ struct sched_group_capacity *sgc = group->sgc;
+
+ capacity += sgc->capacity;
+ min_capacity = min(sgc->min_capacity, min_capacity);
+ max_capacity = max(sgc->max_capacity, max_capacity);
+ group = group->next;
+ } while (group != child->groups);
+ }
+
+ sdg->sgc->capacity = capacity;
+ sdg->sgc->min_capacity = min_capacity;
+ sdg->sgc->max_capacity = max_capacity;
+}
+
+/*
+ * Check whether the capacity of the rq has been noticeably reduced by side
+ * activity. The imbalance_pct is used for the threshold.
+ * Return true is the capacity is reduced
+ */
+static inline int
+check_cpu_capacity(struct rq *rq, struct sched_domain *sd)
+{
+ return ((rq->cpu_capacity * sd->imbalance_pct) <
+ (rq->cpu_capacity_orig * 100));
+}
+
+/*
+ * Check whether a rq has a misfit task and if it looks like we can actually
+ * help that task: we can migrate the task to a CPU of higher capacity, or
+ * the task's current CPU is heavily pressured.
+ */
+static inline int check_misfit_status(struct rq *rq, struct sched_domain *sd)
+{
+ return rq->misfit_task_load &&
+ (rq->cpu_capacity_orig < rq->rd->max_cpu_capacity.val ||
+ check_cpu_capacity(rq, sd));
+}
+
+/*
+ * Group imbalance indicates (and tries to solve) the problem where balancing
+ * groups is inadequate due to ->cpus_ptr constraints.
+ *
+ * Imagine a situation of two groups of 4 CPUs each and 4 tasks each with a
+ * cpumask covering 1 CPU of the first group and 3 CPUs of the second group.
+ * Something like:
+ *
+ * { 0 1 2 3 } { 4 5 6 7 }
+ * * * * *
+ *
+ * If we were to balance group-wise we'd place two tasks in the first group and
+ * two tasks in the second group. Clearly this is undesired as it will overload
+ * cpu 3 and leave one of the CPUs in the second group unused.
+ *
+ * The current solution to this issue is detecting the skew in the first group
+ * by noticing the lower domain failed to reach balance and had difficulty
+ * moving tasks due to affinity constraints.
+ *
+ * When this is so detected; this group becomes a candidate for busiest; see
+ * update_sd_pick_busiest(). And calculate_imbalance() and
+ * find_busiest_group() avoid some of the usual balance conditions to allow it
+ * to create an effective group imbalance.
+ *
+ * This is a somewhat tricky proposition since the next run might not find the
+ * group imbalance and decide the groups need to be balanced again. A most
+ * subtle and fragile situation.
+ */
+
+static inline int sg_imbalanced(struct sched_group *group)
+{
+ return group->sgc->imbalance;
+}
+
+/*
+ * group_has_capacity returns true if the group has spare capacity that could
+ * be used by some tasks.
+ * We consider that a group has spare capacity if the * number of task is
+ * smaller than the number of CPUs or if the utilization is lower than the
+ * available capacity for CFS tasks.
+ * For the latter, we use a threshold to stabilize the state, to take into
+ * account the variance of the tasks' load and to return true if the available
+ * capacity in meaningful for the load balancer.
+ * As an example, an available capacity of 1% can appear but it doesn't make
+ * any benefit for the load balance.
+ */
+static inline bool
+group_has_capacity(struct lb_env *env, struct sg_lb_stats *sgs)
+{
+ if (sgs->sum_nr_running < sgs->group_weight)
+ return true;
+
+ if ((sgs->group_capacity * 100) >
+ (sgs->group_util * env->sd->imbalance_pct))
+ return true;
+
+ return false;
+}
+
+/*
+ * group_is_overloaded returns true if the group has more tasks than it can
+ * handle.
+ * group_is_overloaded is not equals to !group_has_capacity because a group
+ * with the exact right number of tasks, has no more spare capacity but is not
+ * overloaded so both group_has_capacity and group_is_overloaded return
+ * false.
+ */
+static inline bool
+group_is_overloaded(struct lb_env *env, struct sg_lb_stats *sgs)
+{
+ if (sgs->sum_nr_running <= sgs->group_weight)
+ return false;
+
+ if ((sgs->group_capacity * 100) <
+ (sgs->group_util * env->sd->imbalance_pct))
+ return true;
+
+ return false;
+}
+
+/*
+ * group_smaller_min_cpu_capacity: Returns true if sched_group sg has smaller
+ * per-CPU capacity than sched_group ref.
+ */
+static inline bool
+group_smaller_min_cpu_capacity(struct sched_group *sg, struct sched_group *ref)
+{
+ return fits_capacity(sg->sgc->min_capacity, ref->sgc->min_capacity);
+}
+
+/*
+ * group_smaller_max_cpu_capacity: Returns true if sched_group sg has smaller
+ * per-CPU capacity_orig than sched_group ref.
+ */
+static inline bool
+group_smaller_max_cpu_capacity(struct sched_group *sg, struct sched_group *ref)
+{
+ return fits_capacity(sg->sgc->max_capacity, ref->sgc->max_capacity);
+}
+
+static inline enum
+group_type group_classify(struct sched_group *group,
+ struct sg_lb_stats *sgs)
+{
+ if (sgs->group_no_capacity)
+ return group_overloaded;
+
+ if (sg_imbalanced(group))
+ return group_imbalanced;
+
+ if (sgs->group_misfit_task_load)
+ return group_misfit_task;
+
+ return group_other;
+}
+
+static bool update_nohz_stats(struct rq *rq, bool force)
+{
+#ifdef CONFIG_NO_HZ_COMMON
+ unsigned int cpu = rq->cpu;
+
+ if (!rq->has_blocked_load)
+ return false;
+
+ if (!cpumask_test_cpu(cpu, nohz.idle_cpus_mask))
+ return false;
+
+ if (!force && !time_after(jiffies, rq->last_blocked_load_update_tick))
+ return true;
+
+ update_blocked_averages(cpu);
+
+ return rq->has_blocked_load;
+#else
+ return false;
+#endif
+}
+
+/**
+ * update_sg_lb_stats - Update sched_group's statistics for load balancing.
+ * @env: The load balancing environment.
+ * @group: sched_group whose statistics are to be updated.
+ * @sgs: variable to hold the statistics for this group.
+ * @sg_status: Holds flag indicating the status of the sched_group
+ */
+static inline void update_sg_lb_stats(struct lb_env *env,
+ struct sched_group *group,
+ struct sg_lb_stats *sgs,
+ int *sg_status)
+{
+ int i, nr_running;
+
+ memset(sgs, 0, sizeof(*sgs));
+
+ for_each_cpu_and(i, sched_group_span(group), env->cpus) {
+ struct rq *rq = cpu_rq(i);
+
+ if ((env->flags & LBF_NOHZ_STATS) && update_nohz_stats(rq, false))
+ env->flags |= LBF_NOHZ_AGAIN;
+
+ sgs->group_load += cpu_runnable_load(rq);
+ sgs->group_util += cpu_util(i);
+ sgs->sum_nr_running += rq->cfs.h_nr_running;
+
+ nr_running = rq->nr_running;
+ if (nr_running > 1)
+ *sg_status |= SG_OVERLOAD;
+
+ if (cpu_overutilized(i))
+ *sg_status |= SG_OVERUTILIZED;
+
+#ifdef CONFIG_NUMA_BALANCING
+ sgs->nr_numa_running += rq->nr_numa_running;
+ sgs->nr_preferred_running += rq->nr_preferred_running;
+#endif
+ /*
+ * No need to call idle_cpu() if nr_running is not 0
+ */
+ if (!nr_running && idle_cpu(i))
+ sgs->idle_cpus++;
+
+ if (env->sd->flags & SD_ASYM_CPUCAPACITY &&
+ sgs->group_misfit_task_load < rq->misfit_task_load) {
+ sgs->group_misfit_task_load = rq->misfit_task_load;
+ *sg_status |= SG_OVERLOAD;
+ }
+ }
+
+ /* Adjust by relative CPU capacity of the group */
+ sgs->group_capacity = group->sgc->capacity;
+ sgs->avg_load = (sgs->group_load*SCHED_CAPACITY_SCALE) / sgs->group_capacity;
+
+ if (sgs->sum_nr_running)
+ sgs->load_per_task = sgs->group_load / sgs->sum_nr_running;
+
+ sgs->group_weight = group->group_weight;
+
+ sgs->group_no_capacity = group_is_overloaded(env, sgs);
+ sgs->group_type = group_classify(group, sgs);
+}
+
+/**
+ * update_sd_pick_busiest - return 1 on busiest group
+ * @env: The load balancing environment.
+ * @sds: sched_domain statistics
+ * @sg: sched_group candidate to be checked for being the busiest
+ * @sgs: sched_group statistics
+ *
+ * Determine if @sg is a busier group than the previously selected
+ * busiest group.
+ *
+ * Return: %true if @sg is a busier group than the previously selected
+ * busiest group. %false otherwise.
+ */
+static bool update_sd_pick_busiest(struct lb_env *env,
+ struct sd_lb_stats *sds,
+ struct sched_group *sg,
+ struct sg_lb_stats *sgs)
+{
+ struct sg_lb_stats *busiest = &sds->busiest_stat;
+
+ /*
+ * Don't try to pull misfit tasks we can't help.
+ * We can use max_capacity here as reduction in capacity on some
+ * CPUs in the group should either be possible to resolve
+ * internally or be covered by avg_load imbalance (eventually).
+ */
+ if (sgs->group_type == group_misfit_task &&
+ (!group_smaller_max_cpu_capacity(sg, sds->local) ||
+ !group_has_capacity(env, &sds->local_stat)))
+ return false;
+
+ if (sgs->group_type > busiest->group_type)
+ return true;
+
+ if (sgs->group_type < busiest->group_type)
+ return false;
+
+ if (sgs->avg_load <= busiest->avg_load)
+ return false;
+
+ if (!(env->sd->flags & SD_ASYM_CPUCAPACITY))
+ goto asym_packing;
+
+ /*
+ * Candidate sg has no more than one task per CPU and
+ * has higher per-CPU capacity. Migrating tasks to less
+ * capable CPUs may harm throughput. Maximize throughput,
+ * power/energy consequences are not considered.
+ */
+ if (sgs->sum_nr_running <= sgs->group_weight &&
+ group_smaller_min_cpu_capacity(sds->local, sg))
+ return false;
+
+ /*
+ * If we have more than one misfit sg go with the biggest misfit.
+ */
+ if (sgs->group_type == group_misfit_task &&
+ sgs->group_misfit_task_load < busiest->group_misfit_task_load)
+ return false;
+
+asym_packing:
+ /* This is the busiest node in its class. */
+ if (!(env->sd->flags & SD_ASYM_PACKING))
+ return true;
+
+ /* No ASYM_PACKING if target CPU is already busy */
+ if (env->idle == CPU_NOT_IDLE)
+ return true;
+ /*
+ * ASYM_PACKING needs to move all the work to the highest
+ * prority CPUs in the group, therefore mark all groups
+ * of lower priority than ourself as busy.
+ */
+ if (sgs->sum_nr_running &&
+ sched_asym_prefer(env->dst_cpu, sg->asym_prefer_cpu)) {
+ if (!sds->busiest)
+ return true;
+
+ /* Prefer to move from lowest priority CPU's work */
+ if (sched_asym_prefer(sds->busiest->asym_prefer_cpu,
+ sg->asym_prefer_cpu))
+ return true;
+ }
+
+ return false;
+}
+
+#ifdef CONFIG_NUMA_BALANCING
+static inline enum fbq_type fbq_classify_group(struct sg_lb_stats *sgs)
+{
+ if (sgs->sum_nr_running > sgs->nr_numa_running)
+ return regular;
+ if (sgs->sum_nr_running > sgs->nr_preferred_running)
+ return remote;
+ return all;
+}
+
+static inline enum fbq_type fbq_classify_rq(struct rq *rq)
+{
+ if (rq->nr_running > rq->nr_numa_running)
+ return regular;
+ if (rq->nr_running > rq->nr_preferred_running)
+ return remote;
+ return all;
+}
+#else
+static inline enum fbq_type fbq_classify_group(struct sg_lb_stats *sgs)
+{
+ return all;
+}
+
+static inline enum fbq_type fbq_classify_rq(struct rq *rq)
+{
+ return regular;
+}
+#endif /* CONFIG_NUMA_BALANCING */
+
+/**
+ * update_sd_lb_stats - Update sched_domain's statistics for load balancing.
+ * @env: The load balancing environment.
+ * @sds: variable to hold the statistics for this sched_domain.
+ */
+static inline void update_sd_lb_stats(struct lb_env *env, struct sd_lb_stats *sds)
+{
+ struct sched_domain *child = env->sd->child;
+ struct sched_group *sg = env->sd->groups;
+ struct sg_lb_stats *local = &sds->local_stat;
+ struct sg_lb_stats tmp_sgs;
+ bool prefer_sibling = child && child->flags & SD_PREFER_SIBLING;
+ int sg_status = 0;
+
+#ifdef CONFIG_NO_HZ_COMMON
+ if (env->idle == CPU_NEWLY_IDLE && READ_ONCE(nohz.has_blocked))
+ env->flags |= LBF_NOHZ_STATS;
+#endif
+
+ do {
+ struct sg_lb_stats *sgs = &tmp_sgs;
+ int local_group;
+
+ local_group = cpumask_test_cpu(env->dst_cpu, sched_group_span(sg));
+ if (local_group) {
+ sds->local = sg;
+ sgs = local;
+
+ if (env->idle != CPU_NEWLY_IDLE ||
+ time_after_eq(jiffies, sg->sgc->next_update))
+ update_group_capacity(env->sd, env->dst_cpu);
+ }
+
+ update_sg_lb_stats(env, sg, sgs, &sg_status);
+
+ if (local_group)
+ goto next_group;
+
+ /*
+ * In case the child domain prefers tasks go to siblings
+ * first, lower the sg capacity so that we'll try
+ * and move all the excess tasks away. We lower the capacity
+ * of a group only if the local group has the capacity to fit
+ * these excess tasks. The extra check prevents the case where
+ * you always pull from the heaviest group when it is already
+ * under-utilized (possible with a large weight task outweighs
+ * the tasks on the system).
+ */
+ if (prefer_sibling && sds->local &&
+ group_has_capacity(env, local) &&
+ (sgs->sum_nr_running > local->sum_nr_running + 1)) {
+ sgs->group_no_capacity = 1;
+ sgs->group_type = group_classify(sg, sgs);
+ }
+
+ if (update_sd_pick_busiest(env, sds, sg, sgs)) {
+ sds->busiest = sg;
+ sds->busiest_stat = *sgs;
+ }
+
+next_group:
+ /* Now, start updating sd_lb_stats */
+ sds->total_running += sgs->sum_nr_running;
+ sds->total_load += sgs->group_load;
+ sds->total_capacity += sgs->group_capacity;
+
+ sg = sg->next;
+ } while (sg != env->sd->groups);
+
+#ifdef CONFIG_NO_HZ_COMMON
+ if ((env->flags & LBF_NOHZ_AGAIN) &&
+ cpumask_subset(nohz.idle_cpus_mask, sched_domain_span(env->sd))) {
+
+ WRITE_ONCE(nohz.next_blocked,
+ jiffies + msecs_to_jiffies(LOAD_AVG_PERIOD));
+ }
+#endif
+
+ if (env->sd->flags & SD_NUMA)
+ env->fbq_type = fbq_classify_group(&sds->busiest_stat);
+
+ env->src_grp_nr_running = sds->busiest_stat.sum_nr_running;
+
+ if (!env->sd->parent) {
+ struct root_domain *rd = env->dst_rq->rd;
+
+ /* update overload indicator if we are at root domain */
+ WRITE_ONCE(rd->overload, sg_status & SG_OVERLOAD);
+
+ /* Update over-utilization (tipping point, U >= 0) indicator */
+ WRITE_ONCE(rd->overutilized, sg_status & SG_OVERUTILIZED);
+ trace_sched_overutilized_tp(rd, sg_status & SG_OVERUTILIZED);
+ } else if (sg_status & SG_OVERUTILIZED) {
+ struct root_domain *rd = env->dst_rq->rd;
+
+ WRITE_ONCE(rd->overutilized, SG_OVERUTILIZED);
+ trace_sched_overutilized_tp(rd, SG_OVERUTILIZED);
+ }
+}
+
+/**
+ * check_asym_packing - Check to see if the group is packed into the
+ * sched domain.
+ *
+ * This is primarily intended to used at the sibling level. Some
+ * cores like POWER7 prefer to use lower numbered SMT threads. In the
+ * case of POWER7, it can move to lower SMT modes only when higher
+ * threads are idle. When in lower SMT modes, the threads will
+ * perform better since they share less core resources. Hence when we
+ * have idle threads, we want them to be the higher ones.
+ *
+ * This packing function is run on idle threads. It checks to see if
+ * the busiest CPU in this domain (core in the P7 case) has a higher
+ * CPU number than the packing function is being run on. Here we are
+ * assuming lower CPU number will be equivalent to lower a SMT thread
+ * number.
+ *
+ * Return: 1 when packing is required and a task should be moved to
+ * this CPU. The amount of the imbalance is returned in env->imbalance.
+ *
+ * @env: The load balancing environment.
+ * @sds: Statistics of the sched_domain which is to be packed
+ */
+static int check_asym_packing(struct lb_env *env, struct sd_lb_stats *sds)
+{
+ int busiest_cpu;
+
+ if (!(env->sd->flags & SD_ASYM_PACKING))
+ return 0;
+
+ if (env->idle == CPU_NOT_IDLE)
+ return 0;
+
+ if (!sds->busiest)
+ return 0;
+
+ busiest_cpu = sds->busiest->asym_prefer_cpu;
+ if (sched_asym_prefer(busiest_cpu, env->dst_cpu))
+ return 0;
+
+ env->imbalance = sds->busiest_stat.group_load;
+
+ return 1;
+}
+
+/**
+ * fix_small_imbalance - Calculate the minor imbalance that exists
+ * amongst the groups of a sched_domain, during
+ * load balancing.
+ * @env: The load balancing environment.
+ * @sds: Statistics of the sched_domain whose imbalance is to be calculated.
+ */
+static inline
+void fix_small_imbalance(struct lb_env *env, struct sd_lb_stats *sds)
+{
+ unsigned long tmp, capa_now = 0, capa_move = 0;
+ unsigned int imbn = 2;
+ unsigned long scaled_busy_load_per_task;
+ struct sg_lb_stats *local, *busiest;
+
+ local = &sds->local_stat;
+ busiest = &sds->busiest_stat;
+
+ if (!local->sum_nr_running)
+ local->load_per_task = cpu_avg_load_per_task(env->dst_cpu);
+ else if (busiest->load_per_task > local->load_per_task)
+ imbn = 1;
+
+ scaled_busy_load_per_task =
+ (busiest->load_per_task * SCHED_CAPACITY_SCALE) /
+ busiest->group_capacity;
+
+ if (busiest->avg_load + scaled_busy_load_per_task >=
+ local->avg_load + (scaled_busy_load_per_task * imbn)) {
+ env->imbalance = busiest->load_per_task;
+ return;
+ }
+
+ /*
+ * OK, we don't have enough imbalance to justify moving tasks,
+ * however we may be able to increase total CPU capacity used by
+ * moving them.
+ */
+
+ capa_now += busiest->group_capacity *
+ min(busiest->load_per_task, busiest->avg_load);
+ capa_now += local->group_capacity *
+ min(local->load_per_task, local->avg_load);
+ capa_now /= SCHED_CAPACITY_SCALE;
+
+ /* Amount of load we'd subtract */
+ if (busiest->avg_load > scaled_busy_load_per_task) {
+ capa_move += busiest->group_capacity *
+ min(busiest->load_per_task,
+ busiest->avg_load - scaled_busy_load_per_task);
+ }
+
+ /* Amount of load we'd add */
+ if (busiest->avg_load * busiest->group_capacity <
+ busiest->load_per_task * SCHED_CAPACITY_SCALE) {
+ tmp = (busiest->avg_load * busiest->group_capacity) /
+ local->group_capacity;
+ } else {
+ tmp = (busiest->load_per_task * SCHED_CAPACITY_SCALE) /
+ local->group_capacity;
+ }
+ capa_move += local->group_capacity *
+ min(local->load_per_task, local->avg_load + tmp);
+ capa_move /= SCHED_CAPACITY_SCALE;
+
+ /* Move if we gain throughput */
+ if (capa_move > capa_now) {
+ env->imbalance = busiest->load_per_task;
+ return;
+ }
+
+ /* We can't see throughput improvement with the load-based
+ * method, but it is possible depending upon group size and
+ * capacity range that there might still be an underutilized
+ * cpu available in an asymmetric capacity system. Do one last
+ * check just in case.
+ */
+ if (env->sd->flags & SD_ASYM_CPUCAPACITY &&
+ busiest->group_type == group_overloaded &&
+ busiest->sum_nr_running > busiest->group_weight &&
+ local->sum_nr_running < local->group_weight &&
+ local->group_capacity < busiest->group_capacity)
+ env->imbalance = busiest->load_per_task;
+}
+
+/**
+ * calculate_imbalance - Calculate the amount of imbalance present within the
+ * groups of a given sched_domain during load balance.
+ * @env: load balance environment
+ * @sds: statistics of the sched_domain whose imbalance is to be calculated.
+ */
+static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *sds)
+{
+ unsigned long max_pull, load_above_capacity = ~0UL;
+ struct sg_lb_stats *local, *busiest;
+
+ local = &sds->local_stat;
+ busiest = &sds->busiest_stat;
+
+ if (busiest->group_type == group_imbalanced) {
+ /*
+ * In the group_imb case we cannot rely on group-wide averages
+ * to ensure CPU-load equilibrium, look at wider averages. XXX
+ */
+ busiest->load_per_task =
+ min(busiest->load_per_task, sds->avg_load);
+ }
+
+ /*
+ * Avg load of busiest sg can be less and avg load of local sg can
+ * be greater than avg load across all sgs of sd because avg load
+ * factors in sg capacity and sgs with smaller group_type are
+ * skipped when updating the busiest sg:
+ */
+ if (busiest->group_type != group_misfit_task &&
+ (busiest->avg_load <= sds->avg_load ||
+ local->avg_load >= sds->avg_load)) {
+ env->imbalance = 0;
+ return fix_small_imbalance(env, sds);
+ }
+
+ /*
+ * If there aren't any idle CPUs, avoid creating some.
+ */
+ if (busiest->group_type == group_overloaded &&
+ local->group_type == group_overloaded) {
+ load_above_capacity = busiest->sum_nr_running * SCHED_CAPACITY_SCALE;
+ if (load_above_capacity > busiest->group_capacity) {
+ load_above_capacity -= busiest->group_capacity;
+ load_above_capacity *= scale_load_down(NICE_0_LOAD);
+ load_above_capacity /= busiest->group_capacity;
+ } else
+ load_above_capacity = ~0UL;
+ }
+
+ /*
+ * We're trying to get all the CPUs to the average_load, so we don't
+ * want to push ourselves above the average load, nor do we wish to
+ * reduce the max loaded CPU below the average load. At the same time,
+ * we also don't want to reduce the group load below the group
+ * capacity. Thus we look for the minimum possible imbalance.
+ */
+ max_pull = min(busiest->avg_load - sds->avg_load, load_above_capacity);
+
+ /* How much load to actually move to equalise the imbalance */
+ env->imbalance = min(
+ max_pull * busiest->group_capacity,
+ (sds->avg_load - local->avg_load) * local->group_capacity
+ ) / SCHED_CAPACITY_SCALE;
+
+ /* Boost imbalance to allow misfit task to be balanced.
+ * Always do this if we are doing a NEWLY_IDLE balance
+ * on the assumption that any tasks we have must not be
+ * long-running (and hence we cannot rely upon load).
+ * However if we are not idle, we should assume the tasks
+ * we have are longer running and not override load-based
+ * calculations above unless we are sure that the local
+ * group is underutilized.
+ */
+ if (busiest->group_type == group_misfit_task &&
+ (env->idle == CPU_NEWLY_IDLE ||
+ local->sum_nr_running < local->group_weight)) {
+ env->imbalance = max_t(long, env->imbalance,
+ busiest->group_misfit_task_load);
+ }
+
+ /*
+ * if *imbalance is less than the average load per runnable task
+ * there is no guarantee that any tasks will be moved so we'll have
+ * a think about bumping its value to force at least one task to be
+ * moved
+ */
+ if (env->imbalance < busiest->load_per_task)
+ return fix_small_imbalance(env, sds);
+}
+
+/******* find_busiest_group() helpers end here *********************/
+
+/**
+ * find_busiest_group - Returns the busiest group within the sched_domain
+ * if there is an imbalance.
+ *
+ * Also calculates the amount of runnable load which should be moved
+ * to restore balance.
+ *
+ * @env: The load balancing environment.
+ *
+ * Return: - The busiest group if imbalance exists.
+ */
+static struct sched_group *find_busiest_group(struct lb_env *env)
+{
+ struct sg_lb_stats *local, *busiest;
+ struct sd_lb_stats sds;
+
+ init_sd_lb_stats(&sds);
+
+ /*
+ * Compute the various statistics relavent for load balancing at
+ * this level.
+ */
+ update_sd_lb_stats(env, &sds);
+
+ if (sched_energy_enabled()) {
+ struct root_domain *rd = env->dst_rq->rd;
+ int out_balance = 1;
+
+ trace_android_rvh_find_busiest_group(sds.busiest, env->dst_rq,
+ &out_balance);
+ if (rcu_dereference(rd->pd) && !READ_ONCE(rd->overutilized)
+ && out_balance)
+ goto out_balanced;
+ }
+
+ local = &sds.local_stat;
+ busiest = &sds.busiest_stat;
+
+ /* ASYM feature bypasses nice load balance check */
+ if (check_asym_packing(env, &sds))
+ return sds.busiest;
+
+ /* There is no busy sibling group to pull tasks from */
+ if (!sds.busiest || busiest->sum_nr_running == 0)
+ goto out_balanced;
+
+ /* XXX broken for overlapping NUMA groups */
+ sds.avg_load = (SCHED_CAPACITY_SCALE * sds.total_load)
+ / sds.total_capacity;
+
+ /*
+ * If the busiest group is imbalanced the below checks don't
+ * work because they assume all things are equal, which typically
+ * isn't true due to cpus_ptr constraints and the like.
+ */
+ if (busiest->group_type == group_imbalanced)
+ goto force_balance;
+
+ /*
+ * When dst_cpu is idle, prevent SMP nice and/or asymmetric group
+ * capacities from resulting in underutilization due to avg_load.
+ */
+ if (env->idle != CPU_NOT_IDLE && group_has_capacity(env, local) &&
+ busiest->group_no_capacity)
+ goto force_balance;
+
+ /* Misfit tasks should be dealt with regardless of the avg load */
+ if (busiest->group_type == group_misfit_task)
+ goto force_balance;
+
+ /*
+ * If the local group is busier than the selected busiest group
+ * don't try and pull any tasks.
+ */
+ if (local->avg_load >= busiest->avg_load)
+ goto out_balanced;
+
+ /*
+ * Don't pull any tasks if this group is already above the domain
+ * average load.
+ */
+ if (local->avg_load >= sds.avg_load)
+ goto out_balanced;
+
+ if (env->idle == CPU_IDLE) {
+ /*
+ * This CPU is idle. If the busiest group is not overloaded
+ * and there is no imbalance between this and busiest group
+ * wrt idle CPUs, it is balanced. The imbalance becomes
+ * significant if the diff is greater than 1 otherwise we
+ * might end up to just move the imbalance on another group
+ */
+ if ((busiest->group_type != group_overloaded) &&
+ (local->idle_cpus <= (busiest->idle_cpus + 1)))
+ goto out_balanced;
+ } else {
+ /*
+ * In the CPU_NEWLY_IDLE, CPU_NOT_IDLE cases, use
+ * imbalance_pct to be conservative.
+ */
+ if (100 * busiest->avg_load <=
+ env->sd->imbalance_pct * local->avg_load)
+ goto out_balanced;
+ }
+
+force_balance:
+ /* Looks like there is an imbalance. Compute it */
+ env->src_grp_type = busiest->group_type;
+ calculate_imbalance(env, &sds);
+ return env->imbalance ? sds.busiest : NULL;
+
+out_balanced:
+ env->imbalance = 0;
+ return NULL;
+}
+
+/*
+ * find_busiest_queue - find the busiest runqueue among the CPUs in the group.
+ */
+static struct rq *find_busiest_queue(struct lb_env *env,
+ struct sched_group *group)
+{
+ struct rq *busiest = NULL, *rq;
+ unsigned long busiest_load = 0, busiest_capacity = 1;
+ int i;
+
+ for_each_cpu_and(i, sched_group_span(group), env->cpus) {
+ unsigned long capacity, load;
+ enum fbq_type rt;
+
+ rq = cpu_rq(i);
+ rt = fbq_classify_rq(rq);
+
+ /*
+ * We classify groups/runqueues into three groups:
+ * - regular: there are !numa tasks
+ * - remote: there are numa tasks that run on the 'wrong' node
+ * - all: there is no distinction
+ *
+ * In order to avoid migrating ideally placed numa tasks,
+ * ignore those when there's better options.
+ *
+ * If we ignore the actual busiest queue to migrate another
+ * task, the next balance pass can still reduce the busiest
+ * queue by moving tasks around inside the node.
+ *
+ * If we cannot move enough load due to this classification
+ * the next pass will adjust the group classification and
+ * allow migration of more tasks.
+ *
+ * Both cases only affect the total convergence complexity.
+ */
+ if (rt > env->fbq_type)
+ continue;
+
+ /*
+ * For ASYM_CPUCAPACITY domains with misfit tasks we simply
+ * seek the "biggest" misfit task.
+ */
+ if (env->src_grp_type == group_misfit_task) {
+ if (rq->misfit_task_load > busiest_load) {
+ busiest_load = rq->misfit_task_load;
+ busiest = rq;
+ }
+
+ continue;
+ }
+
+ capacity = capacity_of(i);
+
+ /*
+ * For ASYM_CPUCAPACITY domains, don't pick a CPU that could
+ * eventually lead to active_balancing high->low capacity.
+ * Higher per-CPU capacity is considered better than balancing
+ * average load.
+ */
+ if (env->sd->flags & SD_ASYM_CPUCAPACITY &&
+ capacity_of(env->dst_cpu) < capacity &&
+ rq->nr_running == 1)
+ continue;
+
+ load = cpu_runnable_load(rq);
+
+ /*
+ * When comparing with imbalance, use cpu_runnable_load()
+ * which is not scaled with the CPU capacity.
+ */
+
+ if (rq->nr_running == 1 && load > env->imbalance &&
+ !check_cpu_capacity(rq, env->sd))
+ continue;
+
+ /*
+ * For the load comparisons with the other CPU's, consider
+ * the cpu_runnable_load() scaled with the CPU capacity, so
+ * that the load can be moved away from the CPU that is
+ * potentially running at a lower capacity.
+ *
+ * Thus we're looking for max(load_i / capacity_i), crosswise
+ * multiplication to rid ourselves of the division works out
+ * to: load_i * capacity_j > load_j * capacity_i; where j is
+ * our previous maximum.
+ */
+ if (load * busiest_capacity > busiest_load * capacity) {
+ busiest_load = load;
+ busiest_capacity = capacity;
+ busiest = rq;
+ }
+ }
+
+ return busiest;
+}
+
+/*
+ * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but
+ * so long as it is large enough.
+ */
+#define MAX_PINNED_INTERVAL 512
+
+static inline bool
+asym_active_balance(struct lb_env *env)
+{
+ /*
+ * ASYM_PACKING needs to force migrate tasks from busy but
+ * lower priority CPUs in order to pack all tasks in the
+ * highest priority CPUs.
+ */
+ return env->idle != CPU_NOT_IDLE && (env->sd->flags & SD_ASYM_PACKING) &&
+ sched_asym_prefer(env->dst_cpu, env->src_cpu);
+}
+
+static inline bool
+voluntary_active_balance(struct lb_env *env)
+{
+ struct sched_domain *sd = env->sd;
+
+ if (asym_active_balance(env))
+ return 1;
+
+ /*
+ * The dst_cpu is idle and the src_cpu CPU has only 1 CFS task.
+ * It's worth migrating the task if the src_cpu's capacity is reduced
+ * because of other sched_class or IRQs if more capacity stays
+ * available on dst_cpu.
+ */
+ if ((env->idle != CPU_NOT_IDLE) &&
+ (env->src_rq->cfs.h_nr_running == 1)) {
+ if ((check_cpu_capacity(env->src_rq, sd)) &&
+ (capacity_of(env->src_cpu)*sd->imbalance_pct < capacity_of(env->dst_cpu)*100))
+ return 1;
+ }
+
+ if (env->src_grp_type == group_misfit_task)
+ return 1;
+
+ return 0;
+}
+
+static int need_active_balance(struct lb_env *env)
+{
+ struct sched_domain *sd = env->sd;
+
+ if (voluntary_active_balance(env))
+ return 1;
+
+ if (env->src_grp_type == group_overloaded && env->src_rq->misfit_task_load)
+ return 1;
+
+ return unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2);
+}
+
+static int active_load_balance_cpu_stop(void *data);
+
+static int should_we_balance(struct lb_env *env)
+{
+ struct sched_group *sg = env->sd->groups;
+ int cpu, balance_cpu = -1;
+
+ /*
+ * Ensure the balancing environment is consistent; can happen
+ * when the softirq triggers 'during' hotplug.
+ */
+ if (!cpumask_test_cpu(env->dst_cpu, env->cpus))
+ return 0;
+
+ /*
+ * In the newly idle case, we will allow all the CPUs
+ * to do the newly idle load balance.
+ */
+ if (env->idle == CPU_NEWLY_IDLE)
+ return 1;
+
+ /* Try to find first idle CPU */
+ for_each_cpu_and(cpu, group_balance_mask(sg), env->cpus) {
+ if (!idle_cpu(cpu))
+ continue;
+
+ balance_cpu = cpu;
+ break;
+ }
+
+ if (balance_cpu == -1)
+ balance_cpu = group_balance_cpu(sg);
+
+ /*
+ * First idle CPU or the first CPU(busiest) in this sched group
+ * is eligible for doing load balancing at this and above domains.
+ */
+ return balance_cpu == env->dst_cpu;
+}
+
+/*
+ * Check this_cpu to ensure it is balanced within domain. Attempt to move
+ * tasks if there is an imbalance.
+ */
+static int load_balance(int this_cpu, struct rq *this_rq,
+ struct sched_domain *sd, enum cpu_idle_type idle,
+ int *continue_balancing)
+{
+ int ld_moved, cur_ld_moved, active_balance = 0;
+ struct sched_domain *sd_parent = sd->parent;
+ struct sched_group *group;
+ struct rq *busiest;
+ struct rq_flags rf;
+ struct cpumask *cpus = this_cpu_cpumask_var_ptr(load_balance_mask);
+
+ struct lb_env env = {
+ .sd = sd,
+ .dst_cpu = this_cpu,
+ .dst_rq = this_rq,
+ .dst_grpmask = group_balance_mask(sd->groups),
+ .idle = idle,
+ .loop_break = sched_nr_migrate_break,
+ .cpus = cpus,
+ .fbq_type = all,
+ .tasks = LIST_HEAD_INIT(env.tasks),
+ };
+
+ cpumask_and(cpus, sched_domain_span(sd), cpu_active_mask);
+
+ schedstat_inc(sd->lb_count[idle]);
+
+redo:
+ if (!should_we_balance(&env)) {
+ *continue_balancing = 0;
+ goto out_balanced;
+ }
+
+ group = find_busiest_group(&env);
+ if (!group) {
+ schedstat_inc(sd->lb_nobusyg[idle]);
+ goto out_balanced;
+ }
+
+ busiest = find_busiest_queue(&env, group);
+ if (!busiest) {
+ schedstat_inc(sd->lb_nobusyq[idle]);
+ goto out_balanced;
+ }
+
+ BUG_ON(busiest == env.dst_rq);
+
+ schedstat_add(sd->lb_imbalance[idle], env.imbalance);
+
+ env.src_cpu = busiest->cpu;
+ env.src_rq = busiest;
+
+ ld_moved = 0;
+ if (busiest->nr_running > 1) {
+ /*
+ * Attempt to move tasks. If find_busiest_group has found
+ * an imbalance but busiest->nr_running <= 1, the group is
+ * still unbalanced. ld_moved simply stays zero, so it is
+ * correctly treated as an imbalance.
+ */
+ env.flags |= LBF_ALL_PINNED;
+ env.loop_max = min(sysctl_sched_nr_migrate, busiest->nr_running);
+
+more_balance:
+ rq_lock_irqsave(busiest, &rf);
+ update_rq_clock(busiest);
+
+ /*
+ * cur_ld_moved - load moved in current iteration
+ * ld_moved - cumulative load moved across iterations
+ */
+ cur_ld_moved = detach_tasks(&env);
+
+ /*
+ * We've detached some tasks from busiest_rq. Every
+ * task is masked "TASK_ON_RQ_MIGRATING", so we can safely
+ * unlock busiest->lock, and we are able to be sure
+ * that nobody can manipulate the tasks in parallel.
+ * See task_rq_lock() family for the details.
+ */
+
+ rq_unlock(busiest, &rf);
+
+ if (cur_ld_moved) {
+ attach_tasks(&env);
+ ld_moved += cur_ld_moved;
+ }
+
+ local_irq_restore(rf.flags);
+
+ if (env.flags & LBF_NEED_BREAK) {
+ env.flags &= ~LBF_NEED_BREAK;
+ goto more_balance;
+ }
+
+ /*
+ * Revisit (affine) tasks on src_cpu that couldn't be moved to
+ * us and move them to an alternate dst_cpu in our sched_group
+ * where they can run. The upper limit on how many times we
+ * iterate on same src_cpu is dependent on number of CPUs in our
+ * sched_group.
+ *
+ * This changes load balance semantics a bit on who can move
+ * load to a given_cpu. In addition to the given_cpu itself
+ * (or a ilb_cpu acting on its behalf where given_cpu is
+ * nohz-idle), we now have balance_cpu in a position to move
+ * load to given_cpu. In rare situations, this may cause
+ * conflicts (balance_cpu and given_cpu/ilb_cpu deciding
+ * _independently_ and at _same_ time to move some load to
+ * given_cpu) causing exceess load to be moved to given_cpu.
+ * This however should not happen so much in practice and
+ * moreover subsequent load balance cycles should correct the
+ * excess load moved.
+ */
+ if ((env.flags & LBF_DST_PINNED) && env.imbalance > 0) {
+
+ /* Prevent to re-select dst_cpu via env's CPUs */
+ __cpumask_clear_cpu(env.dst_cpu, env.cpus);
+
+ env.dst_rq = cpu_rq(env.new_dst_cpu);
+ env.dst_cpu = env.new_dst_cpu;
+ env.flags &= ~LBF_DST_PINNED;
+ env.loop = 0;
+ env.loop_break = sched_nr_migrate_break;
+
+ /*
+ * Go back to "more_balance" rather than "redo" since we
+ * need to continue with same src_cpu.
+ */
+ goto more_balance;
+ }
+
+ /*
+ * We failed to reach balance because of affinity.
+ */
+ if (sd_parent) {
+ int *group_imbalance = &sd_parent->groups->sgc->imbalance;
+
+ if ((env.flags & LBF_SOME_PINNED) && env.imbalance > 0)
+ *group_imbalance = 1;
+ }
+
+ /* All tasks on this runqueue were pinned by CPU affinity */
+ if (unlikely(env.flags & LBF_ALL_PINNED)) {
+ __cpumask_clear_cpu(cpu_of(busiest), cpus);
+ /*
+ * Attempting to continue load balancing at the current
+ * sched_domain level only makes sense if there are
+ * active CPUs remaining as possible busiest CPUs to
+ * pull load from which are not contained within the
+ * destination group that is receiving any migrated
+ * load.
+ */
+ if (!cpumask_subset(cpus, env.dst_grpmask)) {
+ env.loop = 0;
+ env.loop_break = sched_nr_migrate_break;
+ goto redo;
+ }
+ goto out_all_pinned;
+ }
+ }
+
+ if (!ld_moved) {
+ schedstat_inc(sd->lb_failed[idle]);
+ /*
+ * Increment the failure counter only on periodic balance.
+ * We do not want newidle balance, which can be very
+ * frequent, pollute the failure counter causing
+ * excessive cache_hot migrations and active balances.
+ */
+ if (idle != CPU_NEWLY_IDLE)
+ if (env.src_grp_nr_running > 1)
+ sd->nr_balance_failed++;
+
+ if (need_active_balance(&env)) {
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&busiest->lock, flags);
+
+ /*
+ * Don't kick the active_load_balance_cpu_stop,
+ * if the curr task on busiest CPU can't be
+ * moved to this_cpu:
+ */
+ if (!cpumask_test_cpu(this_cpu, busiest->curr->cpus_ptr)) {
+ raw_spin_unlock_irqrestore(&busiest->lock,
+ flags);
+ env.flags |= LBF_ALL_PINNED;
+ goto out_one_pinned;
+ }
+
+ /*
+ * ->active_balance synchronizes accesses to
+ * ->active_balance_work. Once set, it's cleared
+ * only after active load balance is finished.
+ */
+ if (!busiest->active_balance) {
+ busiest->active_balance = 1;
+ busiest->push_cpu = this_cpu;
+ active_balance = 1;
+ }
+ raw_spin_unlock_irqrestore(&busiest->lock, flags);
+
+ if (active_balance) {
+ stop_one_cpu_nowait(cpu_of(busiest),
+ active_load_balance_cpu_stop, busiest,
+ &busiest->active_balance_work);
+ }
+
+ /* We've kicked active balancing, force task migration. */
+ sd->nr_balance_failed = sd->cache_nice_tries+1;
+ }
+ } else
+ sd->nr_balance_failed = 0;
+
+ if (likely(!active_balance) || voluntary_active_balance(&env)) {
+ /* We were unbalanced, so reset the balancing interval */
+ sd->balance_interval = sd->min_interval;
+ } else {
+ /*
+ * If we've begun active balancing, start to back off. This
+ * case may not be covered by the all_pinned logic if there
+ * is only 1 task on the busy runqueue (because we don't call
+ * detach_tasks).
+ */
+ if (sd->balance_interval < sd->max_interval)
+ sd->balance_interval *= 2;
+ }
+
+ goto out;
+
+out_balanced:
+ /*
+ * We reach balance although we may have faced some affinity
+ * constraints. Clear the imbalance flag only if other tasks got
+ * a chance to move and fix the imbalance.
+ */
+ if (sd_parent && !(env.flags & LBF_ALL_PINNED)) {
+ int *group_imbalance = &sd_parent->groups->sgc->imbalance;
+
+ if (*group_imbalance)
+ *group_imbalance = 0;
+ }
+
+out_all_pinned:
+ /*
+ * We reach balance because all tasks are pinned at this level so
+ * we can't migrate them. Let the imbalance flag set so parent level
+ * can try to migrate them.
+ */
+ schedstat_inc(sd->lb_balanced[idle]);
+
+ sd->nr_balance_failed = 0;
+
+out_one_pinned:
+ ld_moved = 0;
+
+ /*
+ * newidle_balance() disregards balance intervals, so we could
+ * repeatedly reach this code, which would lead to balance_interval
+ * skyrocketting in a short amount of time. Skip the balance_interval
+ * increase logic to avoid that.
+ */
+ if (env.idle == CPU_NEWLY_IDLE)
+ goto out;
+
+ /* tune up the balancing interval */
+ if ((env.flags & LBF_ALL_PINNED &&
+ sd->balance_interval < MAX_PINNED_INTERVAL) ||
+ sd->balance_interval < sd->max_interval)
+ sd->balance_interval *= 2;
+out:
+ return ld_moved;
+}
+
+static inline unsigned long
+get_sd_balance_interval(struct sched_domain *sd, int cpu_busy)
+{
+ unsigned long interval = sd->balance_interval;
+
+ if (cpu_busy)
+ interval *= sd->busy_factor;
+
+ /* scale ms to jiffies */
+ interval = msecs_to_jiffies(interval);
+ interval = clamp(interval, 1UL, max_load_balance_interval);
+
+ return interval;
+}
+
+static inline void
+update_next_balance(struct sched_domain *sd, unsigned long *next_balance)
+{
+ unsigned long interval, next;
+
+ /* used by idle balance, so cpu_busy = 0 */
+ interval = get_sd_balance_interval(sd, 0);
+ next = sd->last_balance + interval;
+
+ if (time_after(*next_balance, next))
+ *next_balance = next;
+}
+
+/*
+ * active_load_balance_cpu_stop is run by the CPU stopper. It pushes
+ * running tasks off the busiest CPU onto idle CPUs. It requires at
+ * least 1 task to be running on each physical CPU where possible, and
+ * avoids physical / logical imbalances.
+ */
+static int active_load_balance_cpu_stop(void *data)
+{
+ struct rq *busiest_rq = data;
+ int busiest_cpu = cpu_of(busiest_rq);
+ int target_cpu = busiest_rq->push_cpu;
+ struct rq *target_rq = cpu_rq(target_cpu);
+ struct sched_domain *sd;
+ struct task_struct *p = NULL;
+ struct rq_flags rf;
+
+ rq_lock_irq(busiest_rq, &rf);
+ /*
+ * Between queueing the stop-work and running it is a hole in which
+ * CPUs can become inactive. We should not move tasks from or to
+ * inactive CPUs.
+ */
+ if (!cpu_active(busiest_cpu) || !cpu_active(target_cpu))
+ goto out_unlock;
+
+ /* Make sure the requested CPU hasn't gone down in the meantime: */
+ if (unlikely(busiest_cpu != smp_processor_id() ||
+ !busiest_rq->active_balance))
+ goto out_unlock;
+
+ /* Is there any task to move? */
+ if (busiest_rq->nr_running <= 1)
+ goto out_unlock;
+
+ /*
+ * This condition is "impossible", if it occurs
+ * we need to fix it. Originally reported by
+ * Bjorn Helgaas on a 128-CPU setup.
+ */
+ BUG_ON(busiest_rq == target_rq);
+
+ /* Search for an sd spanning us and the target CPU. */
+ rcu_read_lock();
+ for_each_domain(target_cpu, sd) {
+ if ((sd->flags & SD_LOAD_BALANCE) &&
+ cpumask_test_cpu(busiest_cpu, sched_domain_span(sd)))
+ break;
+ }
+
+ if (likely(sd)) {
+ struct lb_env env = {
+ .sd = sd,
+ .dst_cpu = target_cpu,
+ .dst_rq = target_rq,
+ .src_cpu = busiest_rq->cpu,
+ .src_rq = busiest_rq,
+ .idle = CPU_IDLE,
+ /*
+ * can_migrate_task() doesn't need to compute new_dst_cpu
+ * for active balancing. Since we have CPU_IDLE, but no
+ * @dst_grpmask we need to make that test go away with lying
+ * about DST_PINNED.
+ */
+ .flags = LBF_DST_PINNED,
+ };
+
+ schedstat_inc(sd->alb_count);
+ update_rq_clock(busiest_rq);
+
+ p = detach_one_task(&env);
+ if (p) {
+ schedstat_inc(sd->alb_pushed);
+ /* Active balancing done, reset the failure counter. */
+ sd->nr_balance_failed = 0;
+ } else {
+ schedstat_inc(sd->alb_failed);
+ }
+ }
+ rcu_read_unlock();
+out_unlock:
+ busiest_rq->active_balance = 0;
+ rq_unlock(busiest_rq, &rf);
+
+ if (p)
+ attach_one_task(target_rq, p);
+
+ local_irq_enable();
+
+ return 0;
+}
+
+static DEFINE_SPINLOCK(balancing);
+
+/*
+ * Scale the max load_balance interval with the number of CPUs in the system.
+ * This trades load-balance latency on larger machines for less cross talk.
+ */
+void update_max_interval(void)
+{
+ max_load_balance_interval = HZ*num_online_cpus()/10;
+}
+
+/*
+ * It checks each scheduling domain to see if it is due to be balanced,
+ * and initiates a balancing operation if so.
+ *
+ * Balancing parameters are set up in init_sched_domains.
+ */
+static void rebalance_domains(struct rq *rq, enum cpu_idle_type idle)
+{
+ int continue_balancing = 1;
+ int cpu = rq->cpu;
+ unsigned long interval;
+ struct sched_domain *sd;
+ /* Earliest time when we have to do rebalance again */
+ unsigned long next_balance = jiffies + 60*HZ;
+ int update_next_balance = 0;
+ int need_serialize, need_decay = 0;
+ u64 max_cost = 0;
+
+ rcu_read_lock();
+ for_each_domain(cpu, sd) {
+ /*
+ * Decay the newidle max times here because this is a regular
+ * visit to all the domains. Decay ~1% per second.
+ */
+ if (time_after(jiffies, sd->next_decay_max_lb_cost)) {
+ sd->max_newidle_lb_cost =
+ (sd->max_newidle_lb_cost * 253) / 256;
+ sd->next_decay_max_lb_cost = jiffies + HZ;
+ need_decay = 1;
+ }
+ max_cost += sd->max_newidle_lb_cost;
+
+ if (!(sd->flags & SD_LOAD_BALANCE))
+ continue;
+
+ /*
+ * Stop the load balance at this level. There is another
+ * CPU in our sched group which is doing load balancing more
+ * actively.
+ */
+ if (!continue_balancing) {
+ if (need_decay)
+ continue;
+ break;
+ }
+
+ interval = get_sd_balance_interval(sd, idle != CPU_IDLE);
+
+ need_serialize = sd->flags & SD_SERIALIZE;
+ if (need_serialize) {
+ if (!spin_trylock(&balancing))
+ goto out;
+ }
+
+ if (time_after_eq(jiffies, sd->last_balance + interval)) {
+ if (load_balance(cpu, rq, sd, idle, &continue_balancing)) {
+ /*
+ * The LBF_DST_PINNED logic could have changed
+ * env->dst_cpu, so we can't know our idle
+ * state even if we migrated tasks. Update it.
+ */
+ idle = idle_cpu(cpu) ? CPU_IDLE : CPU_NOT_IDLE;
+ }
+ sd->last_balance = jiffies;
+ interval = get_sd_balance_interval(sd, idle != CPU_IDLE);
+ }
+ if (need_serialize)
+ spin_unlock(&balancing);
+out:
+ if (time_after(next_balance, sd->last_balance + interval)) {
+ next_balance = sd->last_balance + interval;
+ update_next_balance = 1;
+ }
+ }
+ if (need_decay) {
+ /*
+ * Ensure the rq-wide value also decays but keep it at a
+ * reasonable floor to avoid funnies with rq->avg_idle.
+ */
+ rq->max_idle_balance_cost =
+ max((u64)sysctl_sched_migration_cost, max_cost);
+ }
+ rcu_read_unlock();
+
+ /*
+ * next_balance will be updated only when there is a need.
+ * When the cpu is attached to null domain for ex, it will not be
+ * updated.
+ */
+ if (likely(update_next_balance)) {
+ rq->next_balance = next_balance;
+
+#ifdef CONFIG_NO_HZ_COMMON
+ /*
+ * If this CPU has been elected to perform the nohz idle
+ * balance. Other idle CPUs have already rebalanced with
+ * nohz_idle_balance() and nohz.next_balance has been
+ * updated accordingly. This CPU is now running the idle load
+ * balance for itself and we need to update the
+ * nohz.next_balance accordingly.
+ */
+ if ((idle == CPU_IDLE) && time_after(nohz.next_balance, rq->next_balance))
+ nohz.next_balance = rq->next_balance;
+#endif
+ }
+}
+
+static inline int on_null_domain(struct rq *rq)
+{
+ return unlikely(!rcu_dereference_sched(rq->sd));
+}
+
+#ifdef CONFIG_NO_HZ_COMMON
+/*
+ * idle load balancing details
+ * - When one of the busy CPUs notice that there may be an idle rebalancing
+ * needed, they will kick the idle load balancer, which then does idle
+ * load balancing for all the idle CPUs.
+ * - HK_FLAG_MISC CPUs are used for this task, because HK_FLAG_SCHED not set
+ * anywhere yet.
+ */
+
+static inline int find_new_ilb(void)
+{
+ int ilb;
+
+ for_each_cpu_and(ilb, nohz.idle_cpus_mask,
+ housekeeping_cpumask(HK_FLAG_MISC)) {
+ if (idle_cpu(ilb))
+ return ilb;
+ }
+
+ return nr_cpu_ids;
+}
+
+/*
+ * Kick a CPU to do the nohz balancing, if it is time for it. We pick any
+ * idle CPU in the HK_FLAG_MISC housekeeping set (if there is one).
+ */
+static void kick_ilb(unsigned int flags)
+{
+ int ilb_cpu;
+
+ /*
+ * Increase nohz.next_balance only when if full ilb is triggered but
+ * not if we only update stats.
+ */
+ if (flags & NOHZ_BALANCE_KICK)
+ nohz.next_balance = jiffies+1;
+
+ ilb_cpu = find_new_ilb();
+
+ if (ilb_cpu >= nr_cpu_ids)
+ return;
+
+ flags = atomic_fetch_or(flags, nohz_flags(ilb_cpu));
+ if (flags & NOHZ_KICK_MASK)
+ return;
+
+ /*
+ * Use smp_send_reschedule() instead of resched_cpu().
+ * This way we generate a sched IPI on the target CPU which
+ * is idle. And the softirq performing nohz idle load balance
+ * will be run before returning from the IPI.
+ */
+ smp_send_reschedule(ilb_cpu);
+}
+
+/*
+ * Current decision point for kicking the idle load balancer in the presence
+ * of idle CPUs in the system.
+ */
+static void nohz_balancer_kick(struct rq *rq)
+{
+ unsigned long now = jiffies;
+ struct sched_domain_shared *sds;
+ struct sched_domain *sd;
+ int nr_busy, i, cpu = rq->cpu;
+ unsigned int flags = 0;
+
+ if (unlikely(rq->idle_balance))
+ return;
+
+ /*
+ * We may be recently in ticked or tickless idle mode. At the first
+ * busy tick after returning from idle, we will update the busy stats.
+ */
+ nohz_balance_exit_idle(rq);
+
+ /*
+ * None are in tickless mode and hence no need for NOHZ idle load
+ * balancing.
+ */
+ if (likely(!atomic_read(&nohz.nr_cpus)))
+ return;
+
+ if (READ_ONCE(nohz.has_blocked) &&
+ time_after(now, READ_ONCE(nohz.next_blocked)))
+ flags = NOHZ_STATS_KICK;
+
+ if (time_before(now, nohz.next_balance))
+ goto out;
+
+ if (rq->nr_running >= 2) {
+ flags = NOHZ_KICK_MASK;
+ goto out;
+ }
+
+ rcu_read_lock();
+
+ sd = rcu_dereference(rq->sd);
+ if (sd) {
+ /*
+ * If there's a CFS task and the current CPU has reduced
+ * capacity; kick the ILB to see if there's a better CPU to run
+ * on.
+ */
+ if (rq->cfs.h_nr_running >= 1 && check_cpu_capacity(rq, sd)) {
+ flags = NOHZ_KICK_MASK;
+ goto unlock;
+ }
+ }
+
+ sd = rcu_dereference(per_cpu(sd_asym_packing, cpu));
+ if (sd) {
+ /*
+ * When ASYM_PACKING; see if there's a more preferred CPU
+ * currently idle; in which case, kick the ILB to move tasks
+ * around.
+ */
+ for_each_cpu_and(i, sched_domain_span(sd), nohz.idle_cpus_mask) {
+ if (sched_asym_prefer(i, cpu)) {
+ flags = NOHZ_KICK_MASK;
+ goto unlock;
+ }
+ }
+ }
+
+ sd = rcu_dereference(per_cpu(sd_asym_cpucapacity, cpu));
+ if (sd) {
+ /*
+ * When ASYM_CPUCAPACITY; see if there's a higher capacity CPU
+ * to run the misfit task on.
+ */
+ if (check_misfit_status(rq, sd)) {
+ flags = NOHZ_KICK_MASK;
+ goto unlock;
+ }
+
+ /*
+ * For asymmetric systems, we do not want to nicely balance
+ * cache use, instead we want to embrace asymmetry and only
+ * ensure tasks have enough CPU capacity.
+ *
+ * Skip the LLC logic because it's not relevant in that case.
+ */
+ goto unlock;
+ }
+
+ sds = rcu_dereference(per_cpu(sd_llc_shared, cpu));
+ if (sds) {
+ /*
+ * If there is an imbalance between LLC domains (IOW we could
+ * increase the overall cache use), we need some less-loaded LLC
+ * domain to pull some load. Likewise, we may need to spread
+ * load within the current LLC domain (e.g. packed SMT cores but
+ * other CPUs are idle). We can't really know from here how busy
+ * the others are - so just get a nohz balance going if it looks
+ * like this LLC domain has tasks we could move.
+ */
+ nr_busy = atomic_read(&sds->nr_busy_cpus);
+ if (nr_busy > 1) {
+ flags = NOHZ_KICK_MASK;
+ goto unlock;
+ }
+ }
+unlock:
+ rcu_read_unlock();
+out:
+ if (flags)
+ kick_ilb(flags);
+}
+
+static void set_cpu_sd_state_busy(int cpu)
+{
+ struct sched_domain *sd;
+
+ rcu_read_lock();
+ sd = rcu_dereference(per_cpu(sd_llc, cpu));
+
+ if (!sd || !sd->nohz_idle)
+ goto unlock;
+ sd->nohz_idle = 0;
+
+ atomic_inc(&sd->shared->nr_busy_cpus);
+unlock:
+ rcu_read_unlock();
+}
+
+void nohz_balance_exit_idle(struct rq *rq)
+{
+ SCHED_WARN_ON(rq != this_rq());
+
+ if (likely(!rq->nohz_tick_stopped))
+ return;
+
+ rq->nohz_tick_stopped = 0;
+ cpumask_clear_cpu(rq->cpu, nohz.idle_cpus_mask);
+ atomic_dec(&nohz.nr_cpus);
+
+ set_cpu_sd_state_busy(rq->cpu);
+}
+
+static void set_cpu_sd_state_idle(int cpu)
+{
+ struct sched_domain *sd;
+
+ rcu_read_lock();
+ sd = rcu_dereference(per_cpu(sd_llc, cpu));
+
+ if (!sd || sd->nohz_idle)
+ goto unlock;
+ sd->nohz_idle = 1;
+
+ atomic_dec(&sd->shared->nr_busy_cpus);
+unlock:
+ rcu_read_unlock();
+}
+
+/*
+ * This routine will record that the CPU is going idle with tick stopped.
+ * This info will be used in performing idle load balancing in the future.
+ */
+void nohz_balance_enter_idle(int cpu)
+{
+ struct rq *rq = cpu_rq(cpu);
+
+ SCHED_WARN_ON(cpu != smp_processor_id());
+
+ /* If this CPU is going down, then nothing needs to be done: */
+ if (!cpu_active(cpu))
+ return;
+
+ /* Spare idle load balancing on CPUs that don't want to be disturbed: */
+ if (!housekeeping_cpu(cpu, HK_FLAG_SCHED))
+ return;
+
+ /*
+ * Can be set safely without rq->lock held
+ * If a clear happens, it will have evaluated last additions because
+ * rq->lock is held during the check and the clear
+ */
+ rq->has_blocked_load = 1;
+
+ /*
+ * The tick is still stopped but load could have been added in the
+ * meantime. We set the nohz.has_blocked flag to trig a check of the
+ * *_avg. The CPU is already part of nohz.idle_cpus_mask so the clear
+ * of nohz.has_blocked can only happen after checking the new load
+ */
+ if (rq->nohz_tick_stopped)
+ goto out;
+
+ /* If we're a completely isolated CPU, we don't play: */
+ if (on_null_domain(rq))
+ return;
+
+ rq->nohz_tick_stopped = 1;
+
+ cpumask_set_cpu(cpu, nohz.idle_cpus_mask);
+ atomic_inc(&nohz.nr_cpus);
+
+ /*
+ * Ensures that if nohz_idle_balance() fails to observe our
+ * @idle_cpus_mask store, it must observe the @has_blocked
+ * store.
+ */
+ smp_mb__after_atomic();
+
+ set_cpu_sd_state_idle(cpu);
+
+out:
+ /*
+ * Each time a cpu enter idle, we assume that it has blocked load and
+ * enable the periodic update of the load of idle cpus
+ */
+ WRITE_ONCE(nohz.has_blocked, 1);
+}
+
+/*
+ * Internal function that runs load balance for all idle cpus. The load balance
+ * can be a simple update of blocked load or a complete load balance with
+ * tasks movement depending of flags.
+ * The function returns false if the loop has stopped before running
+ * through all idle CPUs.
+ */
+static bool _nohz_idle_balance(struct rq *this_rq, unsigned int flags,
+ enum cpu_idle_type idle)
+{
+ /* Earliest time when we have to do rebalance again */
+ unsigned long now = jiffies;
+ unsigned long next_balance = now + 60*HZ;
+ bool has_blocked_load = false;
+ int update_next_balance = 0;
+ int this_cpu = this_rq->cpu;
+ int balance_cpu;
+ int ret = false;
+ struct rq *rq;
+
+ SCHED_WARN_ON((flags & NOHZ_KICK_MASK) == NOHZ_BALANCE_KICK);
+
+ /*
+ * We assume there will be no idle load after this update and clear
+ * the has_blocked flag. If a cpu enters idle in the mean time, it will
+ * set the has_blocked flag and trig another update of idle load.
+ * Because a cpu that becomes idle, is added to idle_cpus_mask before
+ * setting the flag, we are sure to not clear the state and not
+ * check the load of an idle cpu.
+ */
+ WRITE_ONCE(nohz.has_blocked, 0);
+
+ /*
+ * Ensures that if we miss the CPU, we must see the has_blocked
+ * store from nohz_balance_enter_idle().
+ */
+ smp_mb();
+
+ for_each_cpu(balance_cpu, nohz.idle_cpus_mask) {
+ if (balance_cpu == this_cpu || !idle_cpu(balance_cpu))
+ continue;
+
+ /*
+ * If this CPU gets work to do, stop the load balancing
+ * work being done for other CPUs. Next load
+ * balancing owner will pick it up.
+ */
+ if (need_resched()) {
+ has_blocked_load = true;
+ goto abort;
+ }
+
+ rq = cpu_rq(balance_cpu);
+
+ has_blocked_load |= update_nohz_stats(rq, true);
+
+ /*
+ * If time for next balance is due,
+ * do the balance.
+ */
+ if (time_after_eq(jiffies, rq->next_balance)) {
+ struct rq_flags rf;
+
+ rq_lock_irqsave(rq, &rf);
+ update_rq_clock(rq);
+ rq_unlock_irqrestore(rq, &rf);
+
+ if (flags & NOHZ_BALANCE_KICK)
+ rebalance_domains(rq, CPU_IDLE);
+ }
+
+ if (time_after(next_balance, rq->next_balance)) {
+ next_balance = rq->next_balance;
+ update_next_balance = 1;
+ }
+ }
+
+ /*
+ * next_balance will be updated only when there is a need.
+ * When the CPU is attached to null domain for ex, it will not be
+ * updated.
+ */
+ if (likely(update_next_balance))
+ nohz.next_balance = next_balance;
+
+ /* Newly idle CPU doesn't need an update */
+ if (idle != CPU_NEWLY_IDLE) {
+ update_blocked_averages(this_cpu);
+ has_blocked_load |= this_rq->has_blocked_load;
+ }
+
+ if (flags & NOHZ_BALANCE_KICK)
+ rebalance_domains(this_rq, CPU_IDLE);
+
+ WRITE_ONCE(nohz.next_blocked,
+ now + msecs_to_jiffies(LOAD_AVG_PERIOD));
+
+ /* The full idle balance loop has been done */
+ ret = true;
+
+abort:
+ /* There is still blocked load, enable periodic update */
+ if (has_blocked_load)
+ WRITE_ONCE(nohz.has_blocked, 1);
+
+ return ret;
+}
+
+/*
+ * In CONFIG_NO_HZ_COMMON case, the idle balance kickee will do the
+ * rebalancing for all the cpus for whom scheduler ticks are stopped.
+ */
+static bool nohz_idle_balance(struct rq *this_rq, enum cpu_idle_type idle)
+{
+ int this_cpu = this_rq->cpu;
+ unsigned int flags;
+
+ if (!(atomic_read(nohz_flags(this_cpu)) & NOHZ_KICK_MASK))
+ return false;
+
+ if (idle != CPU_IDLE) {
+ atomic_andnot(NOHZ_KICK_MASK, nohz_flags(this_cpu));
+ return false;
+ }
+
+ /* could be _relaxed() */
+ flags = atomic_fetch_andnot(NOHZ_KICK_MASK, nohz_flags(this_cpu));
+ if (!(flags & NOHZ_KICK_MASK))
+ return false;
+
+ _nohz_idle_balance(this_rq, flags, idle);
+
+ return true;
+}
+
+static void nohz_newidle_balance(struct rq *this_rq)
+{
+ int this_cpu = this_rq->cpu;
+
+ /*
+ * This CPU doesn't want to be disturbed by scheduler
+ * housekeeping
+ */
+ if (!housekeeping_cpu(this_cpu, HK_FLAG_SCHED))
+ return;
+
+ /* Will wake up very soon. No time for doing anything else*/
+ if (this_rq->avg_idle < sysctl_sched_migration_cost)
+ return;
+
+ /* Don't need to update blocked load of idle CPUs*/
+ if (!READ_ONCE(nohz.has_blocked) ||
+ time_before(jiffies, READ_ONCE(nohz.next_blocked)))
+ return;
+
+ raw_spin_unlock(&this_rq->lock);
+ /*
+ * This CPU is going to be idle and blocked load of idle CPUs
+ * need to be updated. Run the ilb locally as it is a good
+ * candidate for ilb instead of waking up another idle CPU.
+ * Kick an normal ilb if we failed to do the update.
+ */
+ if (!_nohz_idle_balance(this_rq, NOHZ_STATS_KICK, CPU_NEWLY_IDLE))
+ kick_ilb(NOHZ_STATS_KICK);
+ raw_spin_lock(&this_rq->lock);
+}
+
+#else /* !CONFIG_NO_HZ_COMMON */
+static inline void nohz_balancer_kick(struct rq *rq) { }
+
+static inline bool nohz_idle_balance(struct rq *this_rq, enum cpu_idle_type idle)
+{
+ return false;
+}
+
+static inline void nohz_newidle_balance(struct rq *this_rq) { }
+#endif /* CONFIG_NO_HZ_COMMON */
+
+/*
+ * idle_balance is called by schedule() if this_cpu is about to become
+ * idle. Attempts to pull tasks from other CPUs.
+ */
+int newidle_balance(struct rq *this_rq, struct rq_flags *rf)
+{
+ unsigned long next_balance = jiffies + HZ;
+ int this_cpu = this_rq->cpu;
+ struct sched_domain *sd;
+ int pulled_task = 0;
+ u64 curr_cost = 0;
+
+ update_misfit_status(NULL, this_rq);
+ /*
+ * We must set idle_stamp _before_ calling idle_balance(), such that we
+ * measure the duration of idle_balance() as idle time.
+ */
+ this_rq->idle_stamp = rq_clock(this_rq);
+
+ /*
+ * Do not pull tasks towards !active CPUs...
+ */
+ if (!cpu_active(this_cpu))
+ return 0;
+
+ /*
+ * This is OK, because current is on_cpu, which avoids it being picked
+ * for load-balance and preemption/IRQs are still disabled avoiding
+ * further scheduler activity on it and we're being very careful to
+ * re-start the picking loop.
+ */
+ rq_unpin_lock(this_rq, rf);
+
+ if (this_rq->avg_idle < sysctl_sched_migration_cost ||
+ !READ_ONCE(this_rq->rd->overload)) {
+
+ rcu_read_lock();
+ sd = rcu_dereference_check_sched_domain(this_rq->sd);
+ if (sd)
+ update_next_balance(sd, &next_balance);
+ rcu_read_unlock();
+
+ nohz_newidle_balance(this_rq);
+
+ goto out;
+ }
+
+ raw_spin_unlock(&this_rq->lock);
+
+ update_blocked_averages(this_cpu);
+ rcu_read_lock();
+ for_each_domain(this_cpu, sd) {
+ int continue_balancing = 1;
+ u64 t0, domain_cost;
+
+ if (!(sd->flags & SD_LOAD_BALANCE))
+ continue;
+
+ if (this_rq->avg_idle < curr_cost + sd->max_newidle_lb_cost) {
+ update_next_balance(sd, &next_balance);
+ break;
+ }
+
+ if (sd->flags & SD_BALANCE_NEWIDLE) {
+ t0 = sched_clock_cpu(this_cpu);
+
+ pulled_task = load_balance(this_cpu, this_rq,
+ sd, CPU_NEWLY_IDLE,
+ &continue_balancing);
+
+ domain_cost = sched_clock_cpu(this_cpu) - t0;
+ if (domain_cost > sd->max_newidle_lb_cost)
+ sd->max_newidle_lb_cost = domain_cost;
+
+ curr_cost += domain_cost;
+ }
+
+ update_next_balance(sd, &next_balance);
+
+ /*
+ * Stop searching for tasks to pull if there are
+ * now runnable tasks on this rq.
+ */
+ if (pulled_task || this_rq->nr_running > 0)
+ break;
+ }
+ rcu_read_unlock();
+
+ raw_spin_lock(&this_rq->lock);
+
+ if (curr_cost > this_rq->max_idle_balance_cost)
+ this_rq->max_idle_balance_cost = curr_cost;
+
+out:
+ /*
+ * While browsing the domains, we released the rq lock, a task could
+ * have been enqueued in the meantime. Since we're not going idle,
+ * pretend we pulled a task.
+ */
+ if (this_rq->cfs.h_nr_running && !pulled_task)
+ pulled_task = 1;
+
+ /* Move the next balance forward */
+ if (time_after(this_rq->next_balance, next_balance))
+ this_rq->next_balance = next_balance;
+
+ /* Is there a task of a high priority class? */
+ if (this_rq->nr_running != this_rq->cfs.h_nr_running)
+ pulled_task = -1;
+
+ if (pulled_task)
+ this_rq->idle_stamp = 0;
+
+ rq_repin_lock(this_rq, rf);
+
+ return pulled_task;
+}
+
+/*
+ * run_rebalance_domains is triggered when needed from the scheduler tick.
+ * Also triggered for nohz idle balancing (with nohz_balancing_kick set).
+ */
+static __latent_entropy void run_rebalance_domains(struct softirq_action *h)
+{
+ struct rq *this_rq = this_rq();
+ enum cpu_idle_type idle = this_rq->idle_balance ?
+ CPU_IDLE : CPU_NOT_IDLE;
+
+ /*
+ * If this CPU has a pending nohz_balance_kick, then do the
+ * balancing on behalf of the other idle CPUs whose ticks are
+ * stopped. Do nohz_idle_balance *before* rebalance_domains to
+ * give the idle CPUs a chance to load balance. Else we may
+ * load balance only within the local sched_domain hierarchy
+ * and abort nohz_idle_balance altogether if we pull some load.
+ */
+ if (nohz_idle_balance(this_rq, idle))
+ return;
+
+ /* normal load balance */
+ update_blocked_averages(this_rq->cpu);
+ rebalance_domains(this_rq, idle);
+}
+
+/*
+ * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing.
+ */
+void trigger_load_balance(struct rq *rq)
+{
+ /* Don't need to rebalance while attached to NULL domain */
+ if (unlikely(on_null_domain(rq)))
+ return;
+
+ if (time_after_eq(jiffies, rq->next_balance))
+ raise_softirq(SCHED_SOFTIRQ);
+
+ nohz_balancer_kick(rq);
+}
+
+static void rq_online_fair(struct rq *rq)
+{
+ update_sysctl();
+
+ update_runtime_enabled(rq);
+}
+
+static void rq_offline_fair(struct rq *rq)
+{
+ update_sysctl();
+
+ /* Ensure any throttled groups are reachable by pick_next_task */
+ unthrottle_offline_cfs_rqs(rq);
+}
+
+#endif /* CONFIG_SMP */
+
+/*
+ * scheduler tick hitting a task of our scheduling class.
+ *
+ * NOTE: This function can be called remotely by the tick offload that
+ * goes along full dynticks. Therefore no local assumption can be made
+ * and everything must be accessed through the @rq and @curr passed in
+ * parameters.
+ */
+static void task_tick_fair(struct rq *rq, struct task_struct *curr, int queued)
+{
+ struct cfs_rq *cfs_rq;
+ struct sched_entity *se = &curr->se;
+
+ for_each_sched_entity(se) {
+ cfs_rq = cfs_rq_of(se);
+ entity_tick(cfs_rq, se, queued);
+ }
+
+ if (static_branch_unlikely(&sched_numa_balancing))
+ task_tick_numa(rq, curr);
+
+ update_misfit_status(curr, rq);
+ update_overutilized_status(task_rq(curr));
+}
+
+/*
+ * called on fork with the child task as argument from the parent's context
+ * - child not yet on the tasklist
+ * - preemption disabled
+ */
+static void task_fork_fair(struct task_struct *p)
+{
+ struct cfs_rq *cfs_rq;
+ struct sched_entity *se = &p->se, *curr;
+ struct rq *rq = this_rq();
+ struct rq_flags rf;
+
+ rq_lock(rq, &rf);
+ update_rq_clock(rq);
+
+ cfs_rq = task_cfs_rq(current);
+ curr = cfs_rq->curr;
+ if (curr) {
+ update_curr(cfs_rq);
+ se->vruntime = curr->vruntime;
+ }
+ place_entity(cfs_rq, se, 1);
+
+ if (sysctl_sched_child_runs_first && curr && entity_before(curr, se)) {
+ /*
+ * Upon rescheduling, sched_class::put_prev_task() will place
+ * 'current' within the tree based on its new key value.
+ */
+ swap(curr->vruntime, se->vruntime);
+ resched_curr(rq);
+ }
+
+ se->vruntime -= cfs_rq->min_vruntime;
+ rq_unlock(rq, &rf);
+}
+
+/*
+ * Priority of the task has changed. Check to see if we preempt
+ * the current task.
+ */
+static void
+prio_changed_fair(struct rq *rq, struct task_struct *p, int oldprio)
+{
+ if (!task_on_rq_queued(p))
+ return;
+
+ /*
+ * Reschedule if we are currently running on this runqueue and
+ * our priority decreased, or if we are not currently running on
+ * this runqueue and our priority is higher than the current's
+ */
+ if (rq->curr == p) {
+ if (p->prio > oldprio)
+ resched_curr(rq);
+ } else
+ check_preempt_curr(rq, p, 0);
+}
+
+static inline bool vruntime_normalized(struct task_struct *p)
+{
+ struct sched_entity *se = &p->se;
+
+ /*
+ * In both the TASK_ON_RQ_QUEUED and TASK_ON_RQ_MIGRATING cases,
+ * the dequeue_entity(.flags=0) will already have normalized the
+ * vruntime.
+ */
+ if (p->on_rq)
+ return true;
+
+ /*
+ * When !on_rq, vruntime of the task has usually NOT been normalized.
+ * But there are some cases where it has already been normalized:
+ *
+ * - A forked child which is waiting for being woken up by
+ * wake_up_new_task().
+ * - A task which has been woken up by try_to_wake_up() and
+ * waiting for actually being woken up by sched_ttwu_pending().
+ */
+ if (!se->sum_exec_runtime ||
+ (p->state == TASK_WAKING && p->sched_remote_wakeup))
+ return true;
+
+ return false;
+}
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+/*
+ * Propagate the changes of the sched_entity across the tg tree to make it
+ * visible to the root
+ */
+static void propagate_entity_cfs_rq(struct sched_entity *se)
+{
+ struct cfs_rq *cfs_rq;
+
+ list_add_leaf_cfs_rq(cfs_rq_of(se));
+
+ /* Start to propagate at parent */
+ se = se->parent;
+
+ for_each_sched_entity(se) {
+ cfs_rq = cfs_rq_of(se);
+
+ if (!cfs_rq_throttled(cfs_rq)){
+ update_load_avg(cfs_rq, se, UPDATE_TG);
+ list_add_leaf_cfs_rq(cfs_rq);
+ continue;
+ }
+
+ if (list_add_leaf_cfs_rq(cfs_rq))
+ break;
+ }
+}
+#else
+static void propagate_entity_cfs_rq(struct sched_entity *se) { }
+#endif
+
+static void detach_entity_cfs_rq(struct sched_entity *se)
+{
+ struct cfs_rq *cfs_rq = cfs_rq_of(se);
+
+ /* Catch up with the cfs_rq and remove our load when we leave */
+ update_load_avg(cfs_rq, se, 0);
+ detach_entity_load_avg(cfs_rq, se);
+ update_tg_load_avg(cfs_rq, false);
+ propagate_entity_cfs_rq(se);
+}
+
+static void attach_entity_cfs_rq(struct sched_entity *se)
+{
+ struct cfs_rq *cfs_rq = cfs_rq_of(se);
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+ /*
+ * Since the real-depth could have been changed (only FAIR
+ * class maintain depth value), reset depth properly.
+ */
+ se->depth = se->parent ? se->parent->depth + 1 : 0;
+#endif
+
+ /* Synchronize entity with its cfs_rq */
+ update_load_avg(cfs_rq, se, sched_feat(ATTACH_AGE_LOAD) ? 0 : SKIP_AGE_LOAD);
+ attach_entity_load_avg(cfs_rq, se, 0);
+ update_tg_load_avg(cfs_rq, false);
+ propagate_entity_cfs_rq(se);
+}
+
+static void detach_task_cfs_rq(struct task_struct *p)
+{
+ struct sched_entity *se = &p->se;
+ struct cfs_rq *cfs_rq = cfs_rq_of(se);
+
+ if (!vruntime_normalized(p)) {
+ /*
+ * Fix up our vruntime so that the current sleep doesn't
+ * cause 'unlimited' sleep bonus.
+ */
+ place_entity(cfs_rq, se, 0);
+ se->vruntime -= cfs_rq->min_vruntime;
+ }
+
+ detach_entity_cfs_rq(se);
+}
+
+static void attach_task_cfs_rq(struct task_struct *p)
+{
+ struct sched_entity *se = &p->se;
+ struct cfs_rq *cfs_rq = cfs_rq_of(se);
+
+ attach_entity_cfs_rq(se);
+
+ if (!vruntime_normalized(p))
+ se->vruntime += cfs_rq->min_vruntime;
+}
+
+static void switched_from_fair(struct rq *rq, struct task_struct *p)
+{
+ detach_task_cfs_rq(p);
+}
+
+static void switched_to_fair(struct rq *rq, struct task_struct *p)
+{
+ attach_task_cfs_rq(p);
+
+ if (task_on_rq_queued(p)) {
+ /*
+ * We were most likely switched from sched_rt, so
+ * kick off the schedule if running, otherwise just see
+ * if we can still preempt the current task.
+ */
+ if (rq->curr == p)
+ resched_curr(rq);
+ else
+ check_preempt_curr(rq, p, 0);
+ }
+}
+
+/* Account for a task changing its policy or group.
+ *
+ * This routine is mostly called to set cfs_rq->curr field when a task
+ * migrates between groups/classes.
+ */
+static void set_next_task_fair(struct rq *rq, struct task_struct *p, bool first)
+{
+ struct sched_entity *se = &p->se;
+
+#ifdef CONFIG_SMP
+ if (task_on_rq_queued(p)) {
+ /*
+ * Move the next running task to the front of the list, so our
+ * cfs_tasks list becomes MRU one.
+ */
+ list_move(&se->group_node, &rq->cfs_tasks);
+ }
+#endif
+
+ for_each_sched_entity(se) {
+ struct cfs_rq *cfs_rq = cfs_rq_of(se);
+
+ set_next_entity(cfs_rq, se);
+ /* ensure bandwidth has been allocated on our new cfs_rq */
+ account_cfs_rq_runtime(cfs_rq, 0);
+ }
+}
+
+void init_cfs_rq(struct cfs_rq *cfs_rq)
+{
+ cfs_rq->tasks_timeline = RB_ROOT_CACHED;
+ cfs_rq->min_vruntime = (u64)(-(1LL << 20));
+#ifndef CONFIG_64BIT
+ cfs_rq->min_vruntime_copy = cfs_rq->min_vruntime;
+#endif
+#ifdef CONFIG_SMP
+ raw_spin_lock_init(&cfs_rq->removed.lock);
+#endif
+}
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+static void task_set_group_fair(struct task_struct *p)
+{
+ struct sched_entity *se = &p->se;
+
+ set_task_rq(p, task_cpu(p));
+ se->depth = se->parent ? se->parent->depth + 1 : 0;
+}
+
+static void task_move_group_fair(struct task_struct *p)
+{
+ detach_task_cfs_rq(p);
+ set_task_rq(p, task_cpu(p));
+
+#ifdef CONFIG_SMP
+ /* Tell se's cfs_rq has been changed -- migrated */
+ p->se.avg.last_update_time = 0;
+#endif
+ attach_task_cfs_rq(p);
+}
+
+static void task_change_group_fair(struct task_struct *p, int type)
+{
+ switch (type) {
+ case TASK_SET_GROUP:
+ task_set_group_fair(p);
+ break;
+
+ case TASK_MOVE_GROUP:
+ task_move_group_fair(p);
+ break;
+ }
+}
+
+void free_fair_sched_group(struct task_group *tg)
+{
+ int i;
+
+ destroy_cfs_bandwidth(tg_cfs_bandwidth(tg));
+
+ for_each_possible_cpu(i) {
+ if (tg->cfs_rq)
+ kfree(tg->cfs_rq[i]);
+ if (tg->se)
+ kfree(tg->se[i]);
+ }
+
+ kfree(tg->cfs_rq);
+ kfree(tg->se);
+}
+
+int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
+{
+ struct sched_entity *se;
+ struct cfs_rq *cfs_rq;
+ int i;
+
+ tg->cfs_rq = kcalloc(nr_cpu_ids, sizeof(cfs_rq), GFP_KERNEL);
+ if (!tg->cfs_rq)
+ goto err;
+ tg->se = kcalloc(nr_cpu_ids, sizeof(se), GFP_KERNEL);
+ if (!tg->se)
+ goto err;
+
+ tg->shares = NICE_0_LOAD;
+
+ init_cfs_bandwidth(tg_cfs_bandwidth(tg));
+
+ for_each_possible_cpu(i) {
+ cfs_rq = kzalloc_node(sizeof(struct cfs_rq),
+ GFP_KERNEL, cpu_to_node(i));
+ if (!cfs_rq)
+ goto err;
+
+ se = kzalloc_node(sizeof(struct sched_entity),
+ GFP_KERNEL, cpu_to_node(i));
+ if (!se)
+ goto err_free_rq;
+
+ init_cfs_rq(cfs_rq);
+ init_tg_cfs_entry(tg, cfs_rq, se, i, parent->se[i]);
+ init_entity_runnable_average(se);
+ }
+
+ return 1;
+
+err_free_rq:
+ kfree(cfs_rq);
+err:
+ return 0;
+}
+
+void online_fair_sched_group(struct task_group *tg)
+{
+ struct sched_entity *se;
+ struct rq_flags rf;
+ struct rq *rq;
+ int i;
+
+ for_each_possible_cpu(i) {
+ rq = cpu_rq(i);
+ se = tg->se[i];
+ rq_lock_irq(rq, &rf);
+ update_rq_clock(rq);
+ attach_entity_cfs_rq(se);
+ sync_throttle(tg, i);
+ rq_unlock_irq(rq, &rf);
+ }
+}
+
+void unregister_fair_sched_group(struct task_group *tg)
+{
+ unsigned long flags;
+ struct rq *rq;
+ int cpu;
+
+ for_each_possible_cpu(cpu) {
+ if (tg->se[cpu])
+ remove_entity_load_avg(tg->se[cpu]);
+
+ /*
+ * Only empty task groups can be destroyed; so we can speculatively
+ * check on_list without danger of it being re-added.
+ */
+ if (!tg->cfs_rq[cpu]->on_list)
+ continue;
+
+ rq = cpu_rq(cpu);
+
+ raw_spin_lock_irqsave(&rq->lock, flags);
+ list_del_leaf_cfs_rq(tg->cfs_rq[cpu]);
+ raw_spin_unlock_irqrestore(&rq->lock, flags);
+ }
+}
+
+void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq,
+ struct sched_entity *se, int cpu,
+ struct sched_entity *parent)
+{
+ struct rq *rq = cpu_rq(cpu);
+
+ cfs_rq->tg = tg;
+ cfs_rq->rq = rq;
+ init_cfs_rq_runtime(cfs_rq);
+
+ tg->cfs_rq[cpu] = cfs_rq;
+ tg->se[cpu] = se;
+
+ /* se could be NULL for root_task_group */
+ if (!se)
+ return;
+
+ if (!parent) {
+ se->cfs_rq = &rq->cfs;
+ se->depth = 0;
+ } else {
+ se->cfs_rq = parent->my_q;
+ se->depth = parent->depth + 1;
+ }
+
+ se->my_q = cfs_rq;
+ /* guarantee group entities always have weight */
+ update_load_set(&se->load, NICE_0_LOAD);
+ se->parent = parent;
+}
+
+static DEFINE_MUTEX(shares_mutex);
+
+int sched_group_set_shares(struct task_group *tg, unsigned long shares)
+{
+ int i;
+
+ /*
+ * We can't change the weight of the root cgroup.
+ */
+ if (!tg->se[0])
+ return -EINVAL;
+
+ shares = clamp(shares, scale_load(MIN_SHARES), scale_load(MAX_SHARES));
+
+ mutex_lock(&shares_mutex);
+ if (tg->shares == shares)
+ goto done;
+
+ tg->shares = shares;
+ for_each_possible_cpu(i) {
+ struct rq *rq = cpu_rq(i);
+ struct sched_entity *se = tg->se[i];
+ struct rq_flags rf;
+
+ /* Propagate contribution to hierarchy */
+ rq_lock_irqsave(rq, &rf);
+ update_rq_clock(rq);
+ for_each_sched_entity(se) {
+ update_load_avg(cfs_rq_of(se), se, UPDATE_TG);
+ update_cfs_group(se);
+ }
+ rq_unlock_irqrestore(rq, &rf);
+ }
+
+done:
+ mutex_unlock(&shares_mutex);
+ return 0;
+}
+#else /* CONFIG_FAIR_GROUP_SCHED */
+
+void free_fair_sched_group(struct task_group *tg) { }
+
+int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
+{
+ return 1;
+}
+
+void online_fair_sched_group(struct task_group *tg) { }
+
+void unregister_fair_sched_group(struct task_group *tg) { }
+
+#endif /* CONFIG_FAIR_GROUP_SCHED */
+
+
+static unsigned int get_rr_interval_fair(struct rq *rq, struct task_struct *task)
+{
+ struct sched_entity *se = &task->se;
+ unsigned int rr_interval = 0;
+
+ /*
+ * Time slice is 0 for SCHED_OTHER tasks that are on an otherwise
+ * idle runqueue:
+ */
+ if (rq->cfs.load.weight)
+ rr_interval = NS_TO_JIFFIES(sched_slice(cfs_rq_of(se), se));
+
+ return rr_interval;
+}
+
+/*
+ * All the scheduling class methods:
+ */
+const struct sched_class fair_sched_class = {
+ .next = &idle_sched_class,
+ .enqueue_task = enqueue_task_fair,
+ .dequeue_task = dequeue_task_fair,
+ .yield_task = yield_task_fair,
+ .yield_to_task = yield_to_task_fair,
+
+ .check_preempt_curr = check_preempt_wakeup,
+
+ .pick_next_task = pick_next_task_fair,
+ .put_prev_task = put_prev_task_fair,
+ .set_next_task = set_next_task_fair,
+
+#ifdef CONFIG_SMP
+ .balance = balance_fair,
+ .select_task_rq = select_task_rq_fair,
+ .migrate_task_rq = migrate_task_rq_fair,
+
+ .rq_online = rq_online_fair,
+ .rq_offline = rq_offline_fair,
+
+ .task_dead = task_dead_fair,
+ .set_cpus_allowed = set_cpus_allowed_common,
+#endif
+
+ .task_tick = task_tick_fair,
+ .task_fork = task_fork_fair,
+
+ .prio_changed = prio_changed_fair,
+ .switched_from = switched_from_fair,
+ .switched_to = switched_to_fair,
+
+ .get_rr_interval = get_rr_interval_fair,
+
+ .update_curr = update_curr_fair,
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+ .task_change_group = task_change_group_fair,
+#endif
+
+#ifdef CONFIG_UCLAMP_TASK
+ .uclamp_enabled = 1,
+#endif
+};
+
+#ifdef CONFIG_SCHED_DEBUG
+void print_cfs_stats(struct seq_file *m, int cpu)
+{
+ struct cfs_rq *cfs_rq, *pos;
+
+ rcu_read_lock();
+ for_each_leaf_cfs_rq_safe(cpu_rq(cpu), cfs_rq, pos)
+ print_cfs_rq(m, cpu, cfs_rq);
+ rcu_read_unlock();
+}
+
+#ifdef CONFIG_NUMA_BALANCING
+void show_numa_stats(struct task_struct *p, struct seq_file *m)
+{
+ int node;
+ unsigned long tsf = 0, tpf = 0, gsf = 0, gpf = 0;
+ struct numa_group *ng;
+
+ rcu_read_lock();
+ ng = rcu_dereference(p->numa_group);
+ for_each_online_node(node) {
+ if (p->numa_faults) {
+ tsf = p->numa_faults[task_faults_idx(NUMA_MEM, node, 0)];
+ tpf = p->numa_faults[task_faults_idx(NUMA_MEM, node, 1)];
+ }
+ if (ng) {
+ gsf = ng->faults[task_faults_idx(NUMA_MEM, node, 0)],
+ gpf = ng->faults[task_faults_idx(NUMA_MEM, node, 1)];
+ }
+ print_numa_stats(m, node, tsf, tpf, gsf, gpf);
+ }
+ rcu_read_unlock();
+}
+#endif /* CONFIG_NUMA_BALANCING */
+#endif /* CONFIG_SCHED_DEBUG */
+
+__init void init_sched_fair_class(void)
+{
+#ifdef CONFIG_SMP
+ open_softirq(SCHED_SOFTIRQ, run_rebalance_domains);
+
+#ifdef CONFIG_NO_HZ_COMMON
+ nohz.next_balance = jiffies;
+ nohz.next_blocked = jiffies;
+ zalloc_cpumask_var(&nohz.idle_cpus_mask, GFP_NOWAIT);
+#endif
+#endif /* SMP */
+
+}
+
+/*
+ * Helper functions to facilitate extracting info from tracepoints.
+ */
+
+const struct sched_avg *sched_trace_cfs_rq_avg(struct cfs_rq *cfs_rq)
+{
+#ifdef CONFIG_SMP
+ return cfs_rq ? &cfs_rq->avg : NULL;
+#else
+ return NULL;
+#endif
+}
+EXPORT_SYMBOL_GPL(sched_trace_cfs_rq_avg);
+
+char *sched_trace_cfs_rq_path(struct cfs_rq *cfs_rq, char *str, int len)
+{
+ if (!cfs_rq) {
+ if (str)
+ strlcpy(str, "(null)", len);
+ else
+ return NULL;
+ }
+
+ cfs_rq_tg_path(cfs_rq, str, len);
+ return str;
+}
+EXPORT_SYMBOL_GPL(sched_trace_cfs_rq_path);
+
+int sched_trace_cfs_rq_cpu(struct cfs_rq *cfs_rq)
+{
+ return cfs_rq ? cpu_of(rq_of(cfs_rq)) : -1;
+}
+EXPORT_SYMBOL_GPL(sched_trace_cfs_rq_cpu);
+
+const struct sched_avg *sched_trace_rq_avg_rt(struct rq *rq)
+{
+#ifdef CONFIG_SMP
+ return rq ? &rq->avg_rt : NULL;
+#else
+ return NULL;
+#endif
+}
+EXPORT_SYMBOL_GPL(sched_trace_rq_avg_rt);
+
+const struct sched_avg *sched_trace_rq_avg_dl(struct rq *rq)
+{
+#ifdef CONFIG_SMP
+ return rq ? &rq->avg_dl : NULL;
+#else
+ return NULL;
+#endif
+}
+EXPORT_SYMBOL_GPL(sched_trace_rq_avg_dl);
+
+const struct sched_avg *sched_trace_rq_avg_irq(struct rq *rq)
+{
+#if defined(CONFIG_SMP) && defined(CONFIG_HAVE_SCHED_AVG_IRQ)
+ return rq ? &rq->avg_irq : NULL;
+#else
+ return NULL;
+#endif
+}
+EXPORT_SYMBOL_GPL(sched_trace_rq_avg_irq);
+
+int sched_trace_rq_cpu(struct rq *rq)
+{
+ return rq ? cpu_of(rq) : -1;
+}
+EXPORT_SYMBOL_GPL(sched_trace_rq_cpu);
+
+const struct cpumask *sched_trace_rd_span(struct root_domain *rd)
+{
+#ifdef CONFIG_SMP
+ return rd ? rd->span : NULL;
+#else
+ return NULL;
+#endif
+}
+EXPORT_SYMBOL_GPL(sched_trace_rd_span);