[T106][ZXW-22]7520V3SCV2.01.01.02P42U09_VEC_V0.8_AP_VEC origin source commit
Change-Id: Ic6e05d89ecd62fc34f82b23dcf306c93764aec4b
diff --git a/ap/os/linux/linux-3.4.x/kernel/sched/fair.c b/ap/os/linux/linux-3.4.x/kernel/sched/fair.c
new file mode 100644
index 0000000..d21498e
--- /dev/null
+++ b/ap/os/linux/linux-3.4.x/kernel/sched/fair.c
@@ -0,0 +1,5609 @@
+/*
+ * 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 <pzijlstr@redhat.com>
+ */
+
+#include <linux/latencytop.h>
+#include <linux/sched.h>
+#include <linux/cpumask.h>
+#include <linux/slab.h>
+#include <linux/profile.h>
+#include <linux/interrupt.h>
+
+#include <trace/events/sched.h>
+
+#include "sched.h"
+
+/*
+ * Targeted preemption latency for CPU-bound tasks:
+ * (default: 6ms * (1 + ilog(ncpus)), units: nanoseconds)
+ *
+ * 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)
+ */
+unsigned int sysctl_sched_latency = 6000000ULL;
+unsigned int normalized_sysctl_sched_latency = 6000000ULL;
+
+/*
+ * The initial- and re-scaling of tunables is configurable
+ * (default SCHED_TUNABLESCALING_LOG = *(1+ilog(ncpus))
+ *
+ * Options are:
+ * SCHED_TUNABLESCALING_NONE - unscaled, always *1
+ * SCHED_TUNABLESCALING_LOG - scaled logarithmical, *1+ilog(ncpus)
+ * SCHED_TUNABLESCALING_LINEAR - scaled linear, *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;
+unsigned int normalized_sysctl_sched_min_granularity = 750000ULL;
+
+/*
+ * 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.
+ * (default: 1 msec * (1 + ilog(ncpus)), units: nanoseconds)
+ *
+ * This option delays the preemption effects of decoupled workloads
+ * and reduces their over-scheduling. Synchronous workloads will still
+ * have immediate wakeup/sleep latencies.
+ */
+unsigned int sysctl_sched_wakeup_granularity = 1000000UL;
+unsigned int normalized_sysctl_sched_wakeup_granularity = 1000000UL;
+
+const_debug unsigned int sysctl_sched_migration_cost = 500000UL;
+
+/*
+ * The exponential sliding window over which load is averaged for shares
+ * distribution.
+ * (default: 10msec)
+ */
+unsigned int __read_mostly sysctl_sched_shares_window = 10000000UL;
+
+#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
+
+/*
+ * 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 int get_update_sysctl_factor(void)
+{
+ unsigned int cpus = min_t(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();
+}
+
+#if BITS_PER_LONG == 32
+# define WMULT_CONST (~0UL)
+#else
+# define WMULT_CONST (1UL << 32)
+#endif
+
+#define WMULT_SHIFT 32
+
+/*
+ * Shift right and round:
+ */
+#define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y))
+
+/*
+ * delta *= weight / lw
+ */
+static unsigned long
+calc_delta_mine(unsigned long delta_exec, unsigned long weight,
+ struct load_weight *lw)
+{
+ u64 tmp;
+
+ /*
+ * weight can be less than 2^SCHED_LOAD_RESOLUTION for task group sched
+ * entities since MIN_SHARES = 2. Treat weight as 1 if less than
+ * 2^SCHED_LOAD_RESOLUTION.
+ */
+ if (likely(weight > (1UL << SCHED_LOAD_RESOLUTION)))
+ tmp = (u64)delta_exec * scale_load_down(weight);
+ else
+ tmp = (u64)delta_exec;
+
+ if (!lw->inv_weight) {
+ unsigned long 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;
+ }
+
+ /*
+ * Check whether we'd overflow the 64-bit multiplication:
+ */
+ if (unlikely(tmp > WMULT_CONST))
+ tmp = SRR(SRR(tmp, WMULT_SHIFT/2) * lw->inv_weight,
+ WMULT_SHIFT/2);
+ else
+ tmp = SRR(tmp * lw->inv_weight, WMULT_SHIFT);
+
+ return (unsigned long)min(tmp, (u64)(unsigned long)LONG_MAX);
+}
+
+
+const struct sched_class fair_sched_class;
+
+/**************************************************************
+ * CFS operations on generic schedulable entities:
+ */
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+
+/* cpu runqueue to which this cfs_rq is attached */
+static inline struct rq *rq_of(struct cfs_rq *cfs_rq)
+{
+ return cfs_rq->rq;
+}
+
+/* An entity is a task if it doesn't "own" a runqueue */
+#define entity_is_task(se) (!se->my_q)
+
+static inline struct task_struct *task_of(struct sched_entity *se)
+{
+#ifdef CONFIG_SCHED_DEBUG
+ WARN_ON_ONCE(!entity_is_task(se));
+#endif
+ 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 list_add_leaf_cfs_rq(struct cfs_rq *cfs_rq)
+{
+ if (!cfs_rq->on_list) {
+ /*
+ * 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.
+ */
+ if (cfs_rq->tg->parent &&
+ cfs_rq->tg->parent->cfs_rq[cpu_of(rq_of(cfs_rq))]->on_list) {
+ list_add_rcu(&cfs_rq->leaf_cfs_rq_list,
+ &rq_of(cfs_rq)->leaf_cfs_rq_list);
+ } else {
+ list_add_tail_rcu(&cfs_rq->leaf_cfs_rq_list,
+ &rq_of(cfs_rq)->leaf_cfs_rq_list);
+ }
+
+ cfs_rq->on_list = 1;
+ }
+}
+
+static inline void list_del_leaf_cfs_rq(struct cfs_rq *cfs_rq)
+{
+ if (cfs_rq->on_list) {
+ list_del_rcu(&cfs_rq->leaf_cfs_rq_list);
+ cfs_rq->on_list = 0;
+ }
+}
+
+/* Iterate thr' all leaf cfs_rq's on a runqueue */
+#define for_each_leaf_cfs_rq(rq, cfs_rq) \
+ list_for_each_entry_rcu(cfs_rq, &rq->leaf_cfs_rq_list, leaf_cfs_rq_list)
+
+/* Do the two (enqueued) entities belong to the same group ? */
+static inline int
+is_same_group(struct sched_entity *se, struct sched_entity *pse)
+{
+ if (se->cfs_rq == pse->cfs_rq)
+ return 1;
+
+ return 0;
+}
+
+static inline struct sched_entity *parent_entity(struct sched_entity *se)
+{
+ return se->parent;
+}
+
+/* return depth at which a sched entity is present in the hierarchy */
+static inline int depth_se(struct sched_entity *se)
+{
+ int depth = 0;
+
+ for_each_sched_entity(se)
+ depth++;
+
+ return depth;
+}
+
+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 = depth_se(*se);
+ pse_depth = depth_se(*pse);
+
+ 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);
+}
+
+static inline struct rq *rq_of(struct cfs_rq *cfs_rq)
+{
+ return container_of(cfs_rq, struct rq, cfs);
+}
+
+#define entity_is_task(se) 1
+
+#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 list_add_leaf_cfs_rq(struct cfs_rq *cfs_rq)
+{
+}
+
+static inline void list_del_leaf_cfs_rq(struct cfs_rq *cfs_rq)
+{
+}
+
+#define for_each_leaf_cfs_rq(rq, cfs_rq) \
+ for (cfs_rq = &rq->cfs; cfs_rq; cfs_rq = NULL)
+
+static inline int
+is_same_group(struct sched_entity *se, struct sched_entity *pse)
+{
+ return 1;
+}
+
+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, unsigned long delta_exec);
+
+/**************************************************************
+ * Scheduling class tree data structure manipulation methods:
+ */
+
+static inline u64 max_vruntime(u64 min_vruntime, u64 vruntime)
+{
+ s64 delta = (s64)(vruntime - min_vruntime);
+ if (delta > 0)
+ min_vruntime = vruntime;
+
+ return min_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)
+{
+ u64 vruntime = cfs_rq->min_vruntime;
+
+ if (cfs_rq->curr)
+ vruntime = cfs_rq->curr->vruntime;
+
+ if (cfs_rq->rb_leftmost) {
+ struct sched_entity *se = rb_entry(cfs_rq->rb_leftmost,
+ struct sched_entity,
+ run_node);
+
+ if (!cfs_rq->curr)
+ vruntime = se->vruntime;
+ else
+ vruntime = min_vruntime(vruntime, se->vruntime);
+ }
+
+ 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_node;
+ struct rb_node *parent = NULL;
+ struct sched_entity *entry;
+ int leftmost = 1;
+
+ /*
+ * 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 = 0;
+ }
+ }
+
+ /*
+ * Maintain a cache of leftmost tree entries (it is frequently
+ * used):
+ */
+ if (leftmost)
+ cfs_rq->rb_leftmost = &se->run_node;
+
+ rb_link_node(&se->run_node, parent, link);
+ rb_insert_color(&se->run_node, &cfs_rq->tasks_timeline);
+}
+
+static void __dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+ if (cfs_rq->rb_leftmost == &se->run_node) {
+ struct rb_node *next_node;
+
+ next_node = rb_next(&se->run_node);
+ cfs_rq->rb_leftmost = next_node;
+ }
+
+ rb_erase(&se->run_node, &cfs_rq->tasks_timeline);
+}
+
+struct sched_entity *__pick_first_entity(struct cfs_rq *cfs_rq)
+{
+ struct rb_node *left = cfs_rq->rb_leftmost;
+
+ 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);
+
+ 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);
+ 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 unsigned long
+calc_delta_fair(unsigned long delta, struct sched_entity *se)
+{
+ if (unlikely(se->load.weight != NICE_0_LOAD))
+ delta = calc_delta_mine(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 (sysctl_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)
+{
+ u64 period = sysctl_sched_latency;
+ unsigned long nr_latency = sched_nr_latency;
+
+ if (unlikely(nr_running > nr_latency)) {
+ period = sysctl_sched_min_granularity;
+ period *= nr_running;
+ }
+
+ return period;
+}
+
+/*
+ * 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_mine(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);
+}
+
+static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update);
+static void update_cfs_shares(struct cfs_rq *cfs_rq);
+
+/*
+ * Update the current task's runtime statistics. Skip current tasks that
+ * are not in our scheduling class.
+ */
+static inline void
+__update_curr(struct cfs_rq *cfs_rq, struct sched_entity *curr,
+ unsigned long delta_exec)
+{
+ unsigned long delta_exec_weighted;
+
+ schedstat_set(curr->statistics.exec_max,
+ max((u64)delta_exec, curr->statistics.exec_max));
+
+ curr->sum_exec_runtime += delta_exec;
+ schedstat_add(cfs_rq, exec_clock, delta_exec);
+ delta_exec_weighted = calc_delta_fair(delta_exec, curr);
+
+ curr->vruntime += delta_exec_weighted;
+ update_min_vruntime(cfs_rq);
+
+#if defined CONFIG_SMP && defined CONFIG_FAIR_GROUP_SCHED
+ cfs_rq->load_unacc_exec_time += delta_exec;
+#endif
+}
+
+static void update_curr(struct cfs_rq *cfs_rq)
+{
+ struct sched_entity *curr = cfs_rq->curr;
+ u64 now = rq_of(cfs_rq)->clock_task;
+ unsigned long delta_exec;
+
+ if (unlikely(!curr))
+ return;
+
+ /*
+ * Get the amount of time the current task was running
+ * since the last time we changed load (this cannot
+ * overflow on 32 bits):
+ */
+ delta_exec = (unsigned long)(now - curr->exec_start);
+ if (!delta_exec)
+ return;
+
+ __update_curr(cfs_rq, curr, delta_exec);
+ curr->exec_start = now;
+
+ if (entity_is_task(curr)) {
+ struct task_struct *curtask = task_of(curr);
+
+ trace_sched_stat_runtime(curtask, delta_exec, curr->vruntime);
+ cpuacct_charge(curtask, delta_exec);
+ account_group_exec_runtime(curtask, delta_exec);
+ }
+
+ account_cfs_rq_runtime(cfs_rq, delta_exec);
+}
+
+static inline void
+update_stats_wait_start(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+ schedstat_set(se->statistics.wait_start, rq_of(cfs_rq)->clock);
+}
+
+/*
+ * Task is being enqueued - update stats:
+ */
+static void update_stats_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+ /*
+ * 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);
+}
+
+static void
+update_stats_wait_end(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+ schedstat_set(se->statistics.wait_max, max(se->statistics.wait_max,
+ rq_of(cfs_rq)->clock - se->statistics.wait_start));
+ schedstat_set(se->statistics.wait_count, se->statistics.wait_count + 1);
+ schedstat_set(se->statistics.wait_sum, se->statistics.wait_sum +
+ rq_of(cfs_rq)->clock - se->statistics.wait_start);
+#ifdef CONFIG_SCHEDSTATS
+ if (entity_is_task(se)) {
+ trace_sched_stat_wait(task_of(se),
+ rq_of(cfs_rq)->clock - se->statistics.wait_start);
+ }
+#endif
+ schedstat_set(se->statistics.wait_start, 0);
+}
+
+static inline void
+update_stats_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+ /*
+ * Mark the end of the wait period if dequeueing a
+ * waiting task:
+ */
+ if (se != cfs_rq->curr)
+ update_stats_wait_end(cfs_rq, se);
+}
+
+/*
+ * 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_of(cfs_rq)->clock_task;
+}
+
+/**************************************************
+ * Scheduling class queueing methods:
+ */
+
+static void
+account_entity_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+ update_load_add(&cfs_rq->load, se->load.weight);
+ if (!parent_entity(se))
+ update_load_add(&rq_of(cfs_rq)->load, se->load.weight);
+#ifdef CONFIG_SMP
+ if (entity_is_task(se))
+ list_add(&se->group_node, &rq_of(cfs_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);
+ if (!parent_entity(se))
+ update_load_sub(&rq_of(cfs_rq)->load, se->load.weight);
+ if (entity_is_task(se))
+ list_del_init(&se->group_node);
+ cfs_rq->nr_running--;
+}
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+/* we need this in update_cfs_load and load-balance functions below */
+static inline int throttled_hierarchy(struct cfs_rq *cfs_rq);
+# ifdef CONFIG_SMP
+static void update_cfs_rq_load_contribution(struct cfs_rq *cfs_rq,
+ int global_update)
+{
+ struct task_group *tg = cfs_rq->tg;
+ long load_avg;
+
+ load_avg = div64_u64(cfs_rq->load_avg, cfs_rq->load_period+1);
+ load_avg -= cfs_rq->load_contribution;
+
+ if (global_update || abs(load_avg) > cfs_rq->load_contribution / 8) {
+ atomic_add(load_avg, &tg->load_weight);
+ cfs_rq->load_contribution += load_avg;
+ }
+}
+
+static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update)
+{
+ u64 period = sysctl_sched_shares_window;
+ u64 now, delta;
+ unsigned long load = cfs_rq->load.weight;
+
+ if (cfs_rq->tg == &root_task_group || throttled_hierarchy(cfs_rq))
+ return;
+
+ now = rq_of(cfs_rq)->clock_task;
+ delta = now - cfs_rq->load_stamp;
+
+ /* truncate load history at 4 idle periods */
+ if (cfs_rq->load_stamp > cfs_rq->load_last &&
+ now - cfs_rq->load_last > 4 * period) {
+ cfs_rq->load_period = 0;
+ cfs_rq->load_avg = 0;
+ delta = period - 1;
+ }
+
+ cfs_rq->load_stamp = now;
+ cfs_rq->load_unacc_exec_time = 0;
+ cfs_rq->load_period += delta;
+ if (load) {
+ cfs_rq->load_last = now;
+ cfs_rq->load_avg += delta * load;
+ }
+
+ /* consider updating load contribution on each fold or truncate */
+ if (global_update || cfs_rq->load_period > period
+ || !cfs_rq->load_period)
+ update_cfs_rq_load_contribution(cfs_rq, global_update);
+
+ while (cfs_rq->load_period > period) {
+ /*
+ * Inline assembly required to prevent the compiler
+ * optimising this loop into a divmod call.
+ * See __iter_div_u64_rem() for another example of this.
+ */
+ asm("" : "+rm" (cfs_rq->load_period));
+ cfs_rq->load_period /= 2;
+ cfs_rq->load_avg /= 2;
+ }
+
+ if (!cfs_rq->curr && !cfs_rq->nr_running && !cfs_rq->load_avg)
+ list_del_leaf_cfs_rq(cfs_rq);
+}
+
+static inline long calc_tg_weight(struct task_group *tg, struct cfs_rq *cfs_rq)
+{
+ long tg_weight;
+
+ /*
+ * Use this CPU's actual weight instead of the last load_contribution
+ * to gain a more accurate current total weight. See
+ * update_cfs_rq_load_contribution().
+ */
+ tg_weight = atomic_read(&tg->load_weight);
+ tg_weight -= cfs_rq->load_contribution;
+ tg_weight += cfs_rq->load.weight;
+
+ return tg_weight;
+}
+
+static long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg)
+{
+ long tg_weight, load, shares;
+
+ tg_weight = calc_tg_weight(tg, cfs_rq);
+ load = cfs_rq->load.weight;
+
+ shares = (tg->shares * load);
+ if (tg_weight)
+ shares /= tg_weight;
+
+ if (shares < MIN_SHARES)
+ shares = MIN_SHARES;
+ if (shares > tg->shares)
+ shares = tg->shares;
+
+ return shares;
+}
+
+static void update_entity_shares_tick(struct cfs_rq *cfs_rq)
+{
+ if (cfs_rq->load_unacc_exec_time > sysctl_sched_shares_window) {
+ update_cfs_load(cfs_rq, 0);
+ update_cfs_shares(cfs_rq);
+ }
+}
+# else /* CONFIG_SMP */
+static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update)
+{
+}
+
+static inline long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg)
+{
+ return tg->shares;
+}
+
+static inline void update_entity_shares_tick(struct cfs_rq *cfs_rq)
+{
+}
+# endif /* CONFIG_SMP */
+static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se,
+ unsigned long weight)
+{
+ if (se->on_rq) {
+ /* commit outstanding execution time */
+ if (cfs_rq->curr == se)
+ update_curr(cfs_rq);
+ account_entity_dequeue(cfs_rq, se);
+ }
+
+ update_load_set(&se->load, weight);
+
+ if (se->on_rq)
+ account_entity_enqueue(cfs_rq, se);
+}
+
+static void update_cfs_shares(struct cfs_rq *cfs_rq)
+{
+ struct task_group *tg;
+ struct sched_entity *se;
+ long shares;
+
+ tg = cfs_rq->tg;
+ se = tg->se[cpu_of(rq_of(cfs_rq))];
+ if (!se || throttled_hierarchy(cfs_rq))
+ return;
+#ifndef CONFIG_SMP
+ if (likely(se->load.weight == tg->shares))
+ return;
+#endif
+ shares = calc_cfs_shares(cfs_rq, tg);
+
+ reweight_entity(cfs_rq_of(se), se, shares);
+}
+#else /* CONFIG_FAIR_GROUP_SCHED */
+static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update)
+{
+}
+
+static inline void update_cfs_shares(struct cfs_rq *cfs_rq)
+{
+}
+
+static inline void update_entity_shares_tick(struct cfs_rq *cfs_rq)
+{
+}
+#endif /* CONFIG_FAIR_GROUP_SCHED */
+
+static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+#ifdef CONFIG_SCHEDSTATS
+ struct task_struct *tsk = NULL;
+
+ if (entity_is_task(se))
+ tsk = task_of(se);
+
+ if (se->statistics.sleep_start) {
+ u64 delta = rq_of(cfs_rq)->clock - se->statistics.sleep_start;
+
+ if ((s64)delta < 0)
+ delta = 0;
+
+ if (unlikely(delta > se->statistics.sleep_max))
+ se->statistics.sleep_max = delta;
+
+ se->statistics.sleep_start = 0;
+ se->statistics.sum_sleep_runtime += delta;
+
+ if (tsk) {
+ account_scheduler_latency(tsk, delta >> 10, 1);
+ trace_sched_stat_sleep(tsk, delta);
+ }
+ }
+ if (se->statistics.block_start) {
+ u64 delta = rq_of(cfs_rq)->clock - se->statistics.block_start;
+
+ if ((s64)delta < 0)
+ delta = 0;
+
+ if (unlikely(delta > se->statistics.block_max))
+ se->statistics.block_max = delta;
+
+ se->statistics.block_start = 0;
+ se->statistics.sum_sleep_runtime += delta;
+
+ if (tsk) {
+ if (tsk->in_iowait) {
+ se->statistics.iowait_sum += delta;
+ se->statistics.iowait_count++;
+ trace_sched_stat_iowait(tsk, delta);
+ }
+
+ trace_sched_stat_blocked(tsk, delta);
+
+ /*
+ * 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);
+ }
+ }
+#endif
+}
+
+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 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;
+ }
+
+ /* ensure we never gain time by being placed backwards. */
+ vruntime = max_vruntime(se->vruntime, vruntime);
+
+ se->vruntime = vruntime;
+}
+
+static void check_enqueue_throttle(struct cfs_rq *cfs_rq);
+
+static void
+enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
+{
+ /*
+ * Update the normalized vruntime before updating min_vruntime
+ * through callig update_curr().
+ */
+ if (!(flags & ENQUEUE_WAKEUP) || (flags & ENQUEUE_WAKING))
+ se->vruntime += cfs_rq->min_vruntime;
+
+ /*
+ * Update run-time statistics of the 'current'.
+ */
+ update_curr(cfs_rq);
+ update_cfs_load(cfs_rq, 0);
+ account_entity_enqueue(cfs_rq, se);
+ update_cfs_shares(cfs_rq);
+
+ if (flags & ENQUEUE_WAKEUP) {
+ place_entity(cfs_rq, se, 0);
+ enqueue_sleeper(cfs_rq, se);
+ }
+
+ update_stats_enqueue(cfs_rq, se);
+ check_spread(cfs_rq, se);
+ if (se != cfs_rq->curr)
+ __enqueue_entity(cfs_rq, se);
+ se->on_rq = 1;
+
+ if (cfs_rq->nr_running == 1) {
+ list_add_leaf_cfs_rq(cfs_rq);
+ 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)
+ cfs_rq->last = NULL;
+ else
+ break;
+ }
+}
+
+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)
+ cfs_rq->next = NULL;
+ else
+ break;
+ }
+}
+
+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)
+ cfs_rq->skip = NULL;
+ else
+ break;
+ }
+}
+
+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);
+
+ update_stats_dequeue(cfs_rq, se);
+ if (flags & DEQUEUE_SLEEP) {
+#ifdef CONFIG_SCHEDSTATS
+ if (entity_is_task(se)) {
+ struct task_struct *tsk = task_of(se);
+
+ if (tsk->state & TASK_INTERRUPTIBLE)
+ se->statistics.sleep_start = rq_of(cfs_rq)->clock;
+ if (tsk->state & TASK_UNINTERRUPTIBLE)
+ se->statistics.block_start = rq_of(cfs_rq)->clock;
+ }
+#endif
+ }
+
+ clear_buddies(cfs_rq, se);
+
+ if (se != cfs_rq->curr)
+ __dequeue_entity(cfs_rq, se);
+ se->on_rq = 0;
+ update_cfs_load(cfs_rq, 0);
+ account_entity_dequeue(cfs_rq, se);
+
+ /*
+ * Normalize the entity after updating the min_vruntime because the
+ * update can refer to the ->curr item and we need to reflect this
+ * movement in our normalized position.
+ */
+ if (!(flags & DEQUEUE_SLEEP))
+ se->vruntime -= cfs_rq->min_vruntime;
+
+ /* return excess runtime on last dequeue */
+ return_cfs_rq_runtime(cfs_rq);
+
+ update_min_vruntime(cfs_rq);
+ update_cfs_shares(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_task(rq_of(cfs_rq)->curr);
+ /*
+ * 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_task(rq_of(cfs_rq)->curr);
+}
+
+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_stats_curr_start(cfs_rq, se);
+ cfs_rq->curr = se;
+#ifdef CONFIG_SCHEDSTATS
+ /*
+ * 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 (rq_of(cfs_rq)->load.weight >= 2*se->load.weight) {
+ se->statistics.slice_max = max(se->statistics.slice_max,
+ se->sum_exec_runtime - se->prev_sum_exec_runtime);
+ }
+#endif
+ 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 *se = __pick_first_entity(cfs_rq);
+ struct sched_entity *left = se;
+
+ /*
+ * 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 = __pick_next_entity(se);
+ 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 void 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);
+ }
+ 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);
+
+ /*
+ * Update share accounting for long-running entities.
+ */
+ update_entity_shares_tick(cfs_rq);
+
+#ifdef CONFIG_SCHED_HRTICK
+ /*
+ * queued ticks are scheduled to match the slice, so don't bother
+ * validating it and just reschedule.
+ */
+ if (queued) {
+ resched_task(rq_of(cfs_rq)->curr);
+ 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 HAVE_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(&__cfs_bandwidth_used);
+}
+
+void cfs_bandwidth_usage_dec(void)
+{
+ static_key_slow_dec(&__cfs_bandwidth_used);
+}
+#else /* HAVE_JUMP_LABEL */
+static bool cfs_bandwidth_used(void)
+{
+ return true;
+}
+
+void cfs_bandwidth_usage_inc(void) {}
+void cfs_bandwidth_usage_dec(void) {}
+#endif /* HAVE_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 and update expiration time.
+ * 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)
+{
+ u64 now;
+
+ if (cfs_b->quota == RUNTIME_INF)
+ return;
+
+ now = sched_clock_cpu(smp_processor_id());
+ cfs_b->runtime = cfs_b->quota;
+ cfs_b->runtime_expires = now + ktime_to_ns(cfs_b->period);
+}
+
+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_rq *cfs_rq)
+{
+ struct task_group *tg = cfs_rq->tg;
+ struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(tg);
+ u64 amount = 0, min_amount, expires;
+
+ /* note: this is a positive sum as runtime_remaining <= 0 */
+ min_amount = sched_cfs_bandwidth_slice() - cfs_rq->runtime_remaining;
+
+ raw_spin_lock(&cfs_b->lock);
+ if (cfs_b->quota == RUNTIME_INF)
+ amount = min_amount;
+ else {
+ /*
+ * If the bandwidth pool has become inactive, then at least one
+ * period must have elapsed since the last consumption.
+ * Refresh the global state and ensure bandwidth timer becomes
+ * active.
+ */
+ if (!cfs_b->timer_active) {
+ __refill_cfs_bandwidth_runtime(cfs_b);
+ __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;
+ }
+ }
+ expires = cfs_b->runtime_expires;
+ raw_spin_unlock(&cfs_b->lock);
+
+ cfs_rq->runtime_remaining += amount;
+ /*
+ * we may have advanced our local expiration to account for allowed
+ * spread between our sched_clock and the one on which runtime was
+ * issued.
+ */
+ if ((s64)(expires - cfs_rq->runtime_expires) > 0)
+ cfs_rq->runtime_expires = expires;
+
+ return cfs_rq->runtime_remaining > 0;
+}
+
+/*
+ * Note: This depends on the synchronization provided by sched_clock and the
+ * fact that rq->clock snapshots this value.
+ */
+static void expire_cfs_rq_runtime(struct cfs_rq *cfs_rq)
+{
+ struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg);
+ struct rq *rq = rq_of(cfs_rq);
+
+ /* if the deadline is ahead of our clock, nothing to do */
+ if (likely((s64)(rq->clock - cfs_rq->runtime_expires) < 0))
+ return;
+
+ if (cfs_rq->runtime_remaining < 0)
+ return;
+
+ /*
+ * If the local deadline has passed we have to consider the
+ * possibility that our sched_clock is 'fast' and the global deadline
+ * has not truly expired.
+ *
+ * Fortunately we can check determine whether this the case by checking
+ * whether the global deadline has advanced.
+ */
+
+ if ((s64)(cfs_rq->runtime_expires - cfs_b->runtime_expires) >= 0) {
+ /* extend local deadline, drift is bounded above by 2 ticks */
+ cfs_rq->runtime_expires += TICK_NSEC;
+ } else {
+ /* global deadline is ahead, expiration has passed */
+ cfs_rq->runtime_remaining = 0;
+ }
+}
+
+static void __account_cfs_rq_runtime(struct cfs_rq *cfs_rq,
+ unsigned long delta_exec)
+{
+ /* dock delta_exec before expiring quota (as it could span periods) */
+ cfs_rq->runtime_remaining -= delta_exec;
+ expire_cfs_rq_runtime(cfs_rq);
+
+ if (likely(cfs_rq->runtime_remaining > 0))
+ 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_task(rq_of(cfs_rq)->curr);
+}
+
+static __always_inline
+void account_cfs_rq_runtime(struct cfs_rq *cfs_rq, unsigned long 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);
+}
+
+/* updated child weight may affect parent so we have to do this bottom up */
+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--;
+#ifdef CONFIG_SMP
+ if (!cfs_rq->throttle_count) {
+ u64 delta = rq->clock_task - cfs_rq->load_stamp;
+
+ /* leaving throttled state, advance shares averaging windows */
+ cfs_rq->load_stamp += delta;
+ cfs_rq->load_last += delta;
+
+ /* update entity weight now that we are on_rq again */
+ update_cfs_shares(cfs_rq);
+ }
+#endif
+
+ 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, record last load */
+ if (!cfs_rq->throttle_count)
+ update_cfs_load(cfs_rq, 0);
+ cfs_rq->throttle_count++;
+
+ return 0;
+}
+
+static void 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, dequeue = 1;
+
+ se = cfs_rq->tg->se[cpu_of(rq_of(cfs_rq))];
+
+ /* account load preceding throttle */
+ 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;
+ 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;
+
+ if (qcfs_rq->load.weight)
+ dequeue = 0;
+ }
+
+ if (!se)
+ rq->nr_running -= task_delta;
+
+ cfs_rq->throttled = 1;
+ cfs_rq->throttled_timestamp = rq->clock;
+ raw_spin_lock(&cfs_b->lock);
+ list_add_tail_rcu(&cfs_rq->throttled_list, &cfs_b->throttled_cfs_rq);
+ if (!cfs_b->timer_active)
+ __start_cfs_bandwidth(cfs_b);
+ raw_spin_unlock(&cfs_b->lock);
+}
+
+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;
+ int enqueue = 1;
+ long task_delta;
+
+ se = cfs_rq->tg->se[cpu_of(rq_of(cfs_rq))];
+
+ cfs_rq->throttled = 0;
+ raw_spin_lock(&cfs_b->lock);
+ cfs_b->throttled_time += rq->clock - cfs_rq->throttled_timestamp;
+ list_del_rcu(&cfs_rq->throttled_list);
+ raw_spin_unlock(&cfs_b->lock);
+ cfs_rq->throttled_timestamp = 0;
+
+ update_rq_clock(rq);
+ /* 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;
+ for_each_sched_entity(se) {
+ if (se->on_rq)
+ enqueue = 0;
+
+ cfs_rq = cfs_rq_of(se);
+ if (enqueue)
+ enqueue_entity(cfs_rq, se, ENQUEUE_WAKEUP);
+ cfs_rq->h_nr_running += task_delta;
+
+ if (cfs_rq_throttled(cfs_rq))
+ break;
+ }
+
+ if (!se)
+ rq->nr_running += task_delta;
+
+ /* determine whether we need to wake up potentially idle cpu */
+ if (rq->curr == rq->idle && rq->cfs.nr_running)
+ resched_task(rq->curr);
+}
+
+static u64 distribute_cfs_runtime(struct cfs_bandwidth *cfs_b,
+ u64 remaining, u64 expires)
+{
+ struct cfs_rq *cfs_rq;
+ u64 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);
+
+ raw_spin_lock(&rq->lock);
+ if (!cfs_rq_throttled(cfs_rq))
+ goto next;
+
+ runtime = -cfs_rq->runtime_remaining + 1;
+ if (runtime > remaining)
+ runtime = remaining;
+ remaining -= runtime;
+
+ cfs_rq->runtime_remaining += runtime;
+ cfs_rq->runtime_expires = expires;
+
+ /* we check whether we're throttled above */
+ if (cfs_rq->runtime_remaining > 0)
+ unthrottle_cfs_rq(cfs_rq);
+
+next:
+ raw_spin_unlock(&rq->lock);
+
+ if (!remaining)
+ break;
+ }
+ rcu_read_unlock();
+
+ return 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)
+{
+ u64 runtime, runtime_expires;
+ int idle = 1, throttled;
+
+ raw_spin_lock(&cfs_b->lock);
+ /* no need to continue the timer with no bandwidth constraint */
+ if (cfs_b->quota == RUNTIME_INF)
+ goto out_unlock;
+
+ throttled = !list_empty(&cfs_b->throttled_cfs_rq);
+ /* idle depends on !throttled (for the case of a large deficit) */
+ idle = cfs_b->idle && !throttled;
+ cfs_b->nr_periods += overrun;
+
+ /* if we're going inactive then everything else can be deferred */
+ if (idle)
+ goto out_unlock;
+
+ /*
+ * if we have relooped after returning idle once, we need to update our
+ * status as actually running, so that other cpus doing
+ * __start_cfs_bandwidth will stop trying to cancel us.
+ */
+ cfs_b->timer_active = 1;
+
+ __refill_cfs_bandwidth_runtime(cfs_b);
+
+ if (!throttled) {
+ /* mark as potentially idle for the upcoming period */
+ cfs_b->idle = 1;
+ goto out_unlock;
+ }
+
+ /* account preceding periods in which throttling occurred */
+ cfs_b->nr_throttled += overrun;
+
+ /*
+ * There are throttled entities so we must first use the new bandwidth
+ * to unthrottle them before making it generally available. This
+ * ensures that all existing debts will be paid before a new cfs_rq is
+ * allowed to run.
+ */
+ runtime = cfs_b->runtime;
+ runtime_expires = cfs_b->runtime_expires;
+ cfs_b->runtime = 0;
+
+ /*
+ * 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.
+ */
+ while (throttled && runtime > 0) {
+ raw_spin_unlock(&cfs_b->lock);
+ /* we can't nest cfs_b->lock while distributing bandwidth */
+ runtime = distribute_cfs_runtime(cfs_b, runtime,
+ runtime_expires);
+ raw_spin_lock(&cfs_b->lock);
+
+ throttled = !list_empty(&cfs_b->throttled_cfs_rq);
+ }
+
+ /* return (any) remaining runtime */
+ 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;
+out_unlock:
+ if (idle)
+ cfs_b->timer_active = 0;
+ raw_spin_unlock(&cfs_b->lock);
+
+ return idle;
+}
+
+/* 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_range_ns. 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;
+ u64 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 < 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;
+
+ start_bandwidth_timer(&cfs_b->slack_timer,
+ ns_to_ktime(cfs_bandwidth_slack_period));
+}
+
+/* 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_rq->runtime_expires == cfs_b->runtime_expires) {
+ 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();
+ u64 expires;
+
+ /* confirm we're still not at a refresh boundary */
+ raw_spin_lock(&cfs_b->lock);
+ if (runtime_refresh_within(cfs_b, min_bandwidth_expiration)) {
+ raw_spin_unlock(&cfs_b->lock);
+ return;
+ }
+
+ if (cfs_b->quota != RUNTIME_INF && cfs_b->runtime > slice) {
+ runtime = cfs_b->runtime;
+ cfs_b->runtime = 0;
+ }
+ expires = cfs_b->runtime_expires;
+ raw_spin_unlock(&cfs_b->lock);
+
+ if (!runtime)
+ return;
+
+ runtime = distribute_cfs_runtime(cfs_b, runtime, expires);
+
+ raw_spin_lock(&cfs_b->lock);
+ if (expires == cfs_b->runtime_expires)
+ cfs_b->runtime = runtime;
+ raw_spin_unlock(&cfs_b->lock);
+}
+
+/*
+ * 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);
+}
+
+/* conditionally throttle active cfs_rq's from put_prev_entity() */
+static void check_cfs_rq_runtime(struct cfs_rq *cfs_rq)
+{
+ if (!cfs_bandwidth_used())
+ return;
+
+ if (likely(!cfs_rq->runtime_enabled || cfs_rq->runtime_remaining > 0))
+ return;
+
+ /*
+ * 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;
+
+ throttle_cfs_rq(cfs_rq);
+}
+
+static inline u64 default_cfs_period(void);
+static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun);
+static void do_sched_cfs_slack_timer(struct cfs_bandwidth *cfs_b);
+
+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;
+}
+
+static enum hrtimer_restart sched_cfs_period_timer(struct hrtimer *timer)
+{
+ struct cfs_bandwidth *cfs_b =
+ container_of(timer, struct cfs_bandwidth, period_timer);
+ ktime_t now;
+ int overrun;
+ int idle = 0;
+
+ for (;;) {
+ now = hrtimer_cb_get_time(timer);
+ overrun = hrtimer_forward(timer, now, cfs_b->period);
+
+ if (!overrun)
+ break;
+
+ idle = do_sched_cfs_period_timer(cfs_b, overrun);
+ }
+
+ 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_REL);
+ 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;
+}
+
+static void init_cfs_rq_runtime(struct cfs_rq *cfs_rq)
+{
+ cfs_rq->runtime_enabled = 0;
+ INIT_LIST_HEAD(&cfs_rq->throttled_list);
+}
+
+/* requires cfs_b->lock, may release to reprogram timer */
+void __start_cfs_bandwidth(struct cfs_bandwidth *cfs_b)
+{
+ /*
+ * The timer may be active because we're trying to set a new bandwidth
+ * period or because we're racing with the tear-down path
+ * (timer_active==0 becomes visible before the hrtimer call-back
+ * terminates). In either case we ensure that it's re-programmed
+ */
+ while (unlikely(hrtimer_active(&cfs_b->period_timer)) &&
+ hrtimer_try_to_cancel(&cfs_b->period_timer) < 0) {
+ /* bounce the lock to allow do_sched_cfs_period_timer to run */
+ raw_spin_unlock(&cfs_b->lock);
+ cpu_relax();
+ raw_spin_lock(&cfs_b->lock);
+ /* if someone else restarted the timer then we're done */
+ if (cfs_b->timer_active)
+ return;
+ }
+
+ cfs_b->timer_active = 1;
+ start_bandwidth_timer(&cfs_b->period_timer, cfs_b->period);
+}
+
+static void destroy_cfs_bandwidth(struct cfs_bandwidth *cfs_b)
+{
+ hrtimer_cancel(&cfs_b->period_timer);
+ hrtimer_cancel(&cfs_b->slack_timer);
+}
+
+static void unthrottle_offline_cfs_rqs(struct rq *rq)
+{
+ struct cfs_rq *cfs_rq;
+
+ for_each_leaf_cfs_rq(rq, cfs_rq) {
+ struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg);
+
+ 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 = cfs_b->quota;
+ if (cfs_rq_throttled(cfs_rq))
+ unthrottle_cfs_rq(cfs_rq);
+ }
+}
+
+#else /* CONFIG_CFS_BANDWIDTH */
+static __always_inline
+void account_cfs_rq_runtime(struct cfs_rq *cfs_rq, unsigned long delta_exec) {}
+static void check_cfs_rq_runtime(struct cfs_rq *cfs_rq) {}
+static void check_enqueue_throttle(struct cfs_rq *cfs_rq) {}
+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 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);
+
+ WARN_ON(task_rq(p) != rq);
+
+ if (cfs_rq->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_task(p);
+ return;
+ }
+
+ /*
+ * Don't schedule slices shorter than 10000ns, that just
+ * doesn't make sense. Rely on vruntime for fairness.
+ */
+ if (rq->curr != p)
+ delta = max_t(s64, 10000LL, delta);
+
+ 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
+
+/*
+ * 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;
+
+ for_each_sched_entity(se) {
+ if (se->on_rq)
+ break;
+ cfs_rq = cfs_rq_of(se);
+ enqueue_entity(cfs_rq, se, flags);
+
+ /*
+ * end evaluation on encountering a throttled cfs_rq
+ *
+ * note: in the case of encountering a throttled cfs_rq we will
+ * post the final h_nr_running increment below.
+ */
+ if (cfs_rq_throttled(cfs_rq))
+ break;
+ cfs_rq->h_nr_running++;
+
+ flags = ENQUEUE_WAKEUP;
+ }
+
+ for_each_sched_entity(se) {
+ cfs_rq = cfs_rq_of(se);
+ cfs_rq->h_nr_running++;
+
+ if (cfs_rq_throttled(cfs_rq))
+ break;
+
+ update_cfs_load(cfs_rq, 0);
+ update_cfs_shares(cfs_rq);
+ }
+
+ if (!se)
+ inc_nr_running(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;
+
+ for_each_sched_entity(se) {
+ cfs_rq = cfs_rq_of(se);
+ dequeue_entity(cfs_rq, se, flags);
+
+ /*
+ * end evaluation on encountering a throttled cfs_rq
+ *
+ * note: in the case of encountering a throttled cfs_rq we will
+ * post the final h_nr_running decrement below.
+ */
+ if (cfs_rq_throttled(cfs_rq))
+ break;
+ cfs_rq->h_nr_running--;
+
+ /* Don't dequeue parent if it has other entities besides us */
+ if (cfs_rq->load.weight) {
+ /*
+ * 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 && parent_entity(se))
+ set_next_buddy(parent_entity(se));
+
+ /* avoid re-evaluating load for this entity */
+ se = parent_entity(se);
+ break;
+ }
+ flags |= DEQUEUE_SLEEP;
+ }
+
+ for_each_sched_entity(se) {
+ cfs_rq = cfs_rq_of(se);
+ cfs_rq->h_nr_running--;
+
+ if (cfs_rq_throttled(cfs_rq))
+ break;
+
+ update_cfs_load(cfs_rq, 0);
+ update_cfs_shares(cfs_rq);
+ }
+
+ if (!se)
+ dec_nr_running(rq);
+ hrtick_update(rq);
+}
+
+#ifdef CONFIG_SMP
+/* Used instead of source_load when we know the type == 0 */
+static unsigned long weighted_cpuload(const int cpu)
+{
+ return cpu_rq(cpu)->load.weight;
+}
+
+/*
+ * Return a low guess at the load of a migration-source cpu weighted
+ * according to the scheduling class and "nice" value.
+ *
+ * We want to under-estimate the load of migration sources, to
+ * balance conservatively.
+ */
+static unsigned long source_load(int cpu, int type)
+{
+ struct rq *rq = cpu_rq(cpu);
+ unsigned long total = weighted_cpuload(cpu);
+
+ if (type == 0 || !sched_feat(LB_BIAS))
+ return total;
+
+ return min(rq->cpu_load[type-1], total);
+}
+
+/*
+ * Return a high guess at the load of a migration-target cpu weighted
+ * according to the scheduling class and "nice" value.
+ */
+static unsigned long target_load(int cpu, int type)
+{
+ struct rq *rq = cpu_rq(cpu);
+ unsigned long total = weighted_cpuload(cpu);
+
+ if (type == 0 || !sched_feat(LB_BIAS))
+ return total;
+
+ return max(rq->cpu_load[type-1], total);
+}
+
+static unsigned long power_of(int cpu)
+{
+ return cpu_rq(cpu)->cpu_power;
+}
+
+static unsigned long cpu_avg_load_per_task(int cpu)
+{
+ struct rq *rq = cpu_rq(cpu);
+ unsigned long nr_running = ACCESS_ONCE(rq->nr_running);
+
+ if (nr_running)
+ return rq->load.weight / nr_running;
+
+ return 0;
+}
+
+
+static void task_waking_fair(struct task_struct *p)
+{
+ 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;
+}
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+/*
+ * effective_load() calculates the load change as seen from the root_task_group
+ *
+ * Adding load to a group doesn't make a group heavier, but can cause movement
+ * of group shares between cpus. Assuming the shares were perfectly aligned one
+ * can calculate the shift in shares.
+ *
+ * Calculate the effective load difference if @wl is added (subtracted) to @tg
+ * on this @cpu and results in a total addition (subtraction) of @wg to the
+ * total group weight.
+ *
+ * Given a runqueue weight distribution (rw_i) we can compute a shares
+ * distribution (s_i) using:
+ *
+ * s_i = rw_i / \Sum rw_j (1)
+ *
+ * Suppose we have 4 CPUs and our @tg is a direct child of the root group and
+ * has 7 equal weight tasks, distributed as below (rw_i), with the resulting
+ * shares distribution (s_i):
+ *
+ * rw_i = { 2, 4, 1, 0 }
+ * s_i = { 2/7, 4/7, 1/7, 0 }
+ *
+ * As per wake_affine() we're interested in the load of two CPUs (the CPU the
+ * task used to run on and the CPU the waker is running on), we need to
+ * compute the effect of waking a task on either CPU and, in case of a sync
+ * wakeup, compute the effect of the current task going to sleep.
+ *
+ * So for a change of @wl to the local @cpu with an overall group weight change
+ * of @wl we can compute the new shares distribution (s'_i) using:
+ *
+ * s'_i = (rw_i + @wl) / (@wg + \Sum rw_j) (2)
+ *
+ * Suppose we're interested in CPUs 0 and 1, and want to compute the load
+ * differences in waking a task to CPU 0. The additional task changes the
+ * weight and shares distributions like:
+ *
+ * rw'_i = { 3, 4, 1, 0 }
+ * s'_i = { 3/8, 4/8, 1/8, 0 }
+ *
+ * We can then compute the difference in effective weight by using:
+ *
+ * dw_i = S * (s'_i - s_i) (3)
+ *
+ * Where 'S' is the group weight as seen by its parent.
+ *
+ * Therefore the effective change in loads on CPU 0 would be 5/56 (3/8 - 2/7)
+ * times the weight of the group. The effect on CPU 1 would be -4/56 (4/8 -
+ * 4/7) times the weight of the group.
+ */
+static long effective_load(struct task_group *tg, int cpu, long wl, long wg)
+{
+ struct sched_entity *se = tg->se[cpu];
+
+ if (!tg->parent) /* the trivial, non-cgroup case */
+ return wl;
+
+ for_each_sched_entity(se) {
+ long w, W;
+
+ tg = se->my_q->tg;
+
+ /*
+ * W = @wg + \Sum rw_j
+ */
+ W = wg + calc_tg_weight(tg, se->my_q);
+
+ /*
+ * w = rw_i + @wl
+ */
+ w = se->my_q->load.weight + wl;
+
+ /*
+ * wl = S * s'_i; see (2)
+ */
+ if (W > 0 && w < W)
+ wl = (w * tg->shares) / W;
+ else
+ wl = tg->shares;
+
+ /*
+ * Per the above, wl is the new se->load.weight value; since
+ * those are clipped to [MIN_SHARES, ...) do so now. See
+ * calc_cfs_shares().
+ */
+ if (wl < MIN_SHARES)
+ wl = MIN_SHARES;
+
+ /*
+ * wl = dw_i = S * (s'_i - s_i); see (3)
+ */
+ wl -= se->load.weight;
+
+ /*
+ * Recursively apply this logic to all parent groups to compute
+ * the final effective load change on the root group. Since
+ * only the @tg group gets extra weight, all parent groups can
+ * only redistribute existing shares. @wl is the shift in shares
+ * resulting from this level per the above.
+ */
+ wg = 0;
+ }
+
+ return wl;
+}
+#else
+
+static inline unsigned long effective_load(struct task_group *tg, int cpu,
+ unsigned long wl, unsigned long wg)
+{
+ return wl;
+}
+
+#endif
+
+static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync)
+{
+ s64 this_load, load;
+ int idx, this_cpu, prev_cpu;
+ unsigned long tl_per_task;
+ struct task_group *tg;
+ unsigned long weight;
+ int balanced;
+
+ idx = sd->wake_idx;
+ this_cpu = smp_processor_id();
+ prev_cpu = task_cpu(p);
+ load = source_load(prev_cpu, idx);
+ this_load = target_load(this_cpu, idx);
+
+ /*
+ * If sync wakeup then subtract the (maximum possible)
+ * effect of the currently running task from the load
+ * of the current CPU:
+ */
+ if (sync) {
+ tg = task_group(current);
+ weight = current->se.load.weight;
+
+ this_load += effective_load(tg, this_cpu, -weight, -weight);
+ load += effective_load(tg, prev_cpu, 0, -weight);
+ }
+
+ tg = task_group(p);
+ weight = p->se.load.weight;
+
+ /*
+ * In low-load situations, where prev_cpu is idle and this_cpu is idle
+ * due to the sync cause above having dropped this_load to 0, we'll
+ * always have an imbalance, but there's really nothing you can do
+ * about that, so that's good too.
+ *
+ * Otherwise check if either cpus are near enough in load to allow this
+ * task to be woken on this_cpu.
+ */
+ if (this_load > 0) {
+ s64 this_eff_load, prev_eff_load;
+
+ this_eff_load = 100;
+ this_eff_load *= power_of(prev_cpu);
+ this_eff_load *= this_load +
+ effective_load(tg, this_cpu, weight, weight);
+
+ prev_eff_load = 100 + (sd->imbalance_pct - 100) / 2;
+ prev_eff_load *= power_of(this_cpu);
+ prev_eff_load *= load + effective_load(tg, prev_cpu, 0, weight);
+
+ balanced = this_eff_load <= prev_eff_load;
+ } else
+ balanced = true;
+
+ /*
+ * If the currently running task will sleep within
+ * a reasonable amount of time then attract this newly
+ * woken task:
+ */
+ if (sync && balanced)
+ return 1;
+
+ schedstat_inc(p, se.statistics.nr_wakeups_affine_attempts);
+ tl_per_task = cpu_avg_load_per_task(this_cpu);
+
+ if (balanced ||
+ (this_load <= load &&
+ this_load + target_load(prev_cpu, idx) <= tl_per_task)) {
+ /*
+ * This domain has SD_WAKE_AFFINE and
+ * p is cache cold in this domain, and
+ * there is no bad imbalance.
+ */
+ schedstat_inc(sd, ttwu_move_affine);
+ schedstat_inc(p, se.statistics.nr_wakeups_affine);
+
+ return 1;
+ }
+ return 0;
+}
+
+/*
+ * find_idlest_group finds and returns the least busy CPU group within the
+ * domain.
+ */
+static struct sched_group *
+find_idlest_group(struct sched_domain *sd, struct task_struct *p,
+ int this_cpu, int load_idx)
+{
+ struct sched_group *idlest = NULL, *group = sd->groups;
+ unsigned long min_load = ULONG_MAX, this_load = 0;
+ int imbalance = 100 + (sd->imbalance_pct-100)/2;
+
+ do {
+ unsigned long load, avg_load;
+ int local_group;
+ int i;
+
+ /* Skip over this group if it has no CPUs allowed */
+ if (!cpumask_intersects(sched_group_cpus(group),
+ tsk_cpus_allowed(p)))
+ continue;
+
+ local_group = cpumask_test_cpu(this_cpu,
+ sched_group_cpus(group));
+
+ /* Tally up the load of all CPUs in the group */
+ avg_load = 0;
+
+ for_each_cpu(i, sched_group_cpus(group)) {
+ /* Bias balancing toward cpus of our domain */
+ if (local_group)
+ load = source_load(i, load_idx);
+ else
+ load = target_load(i, load_idx);
+
+ avg_load += load;
+ }
+
+ /* Adjust by relative CPU power of the group */
+ avg_load = (avg_load * SCHED_POWER_SCALE) / group->sgp->power;
+
+ if (local_group) {
+ this_load = avg_load;
+ } else if (avg_load < min_load) {
+ min_load = avg_load;
+ idlest = group;
+ }
+ } while (group = group->next, group != sd->groups);
+
+ if (!idlest || 100*this_load < imbalance*min_load)
+ return NULL;
+ return idlest;
+}
+
+/*
+ * find_idlest_cpu - find the idlest cpu among the cpus in group.
+ */
+static int
+find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu)
+{
+ unsigned long load, min_load = ULONG_MAX;
+ int idlest = -1;
+ int i;
+
+ /* Traverse only the allowed CPUs */
+ for_each_cpu_and(i, sched_group_cpus(group), tsk_cpus_allowed(p)) {
+ load = weighted_cpuload(i);
+
+ if (load < min_load || (load == min_load && i == this_cpu)) {
+ min_load = load;
+ idlest = i;
+ }
+ }
+
+ return idlest;
+}
+
+/*
+ * Try and locate an idle CPU in the sched_domain.
+ */
+static int select_idle_sibling(struct task_struct *p, int target)
+{
+ int cpu = smp_processor_id();
+ int prev_cpu = task_cpu(p);
+ struct sched_domain *sd;
+ struct sched_group *sg;
+ int i;
+
+ /*
+ * If the task is going to be woken-up on this cpu and if it is
+ * already idle, then it is the right target.
+ */
+ if (target == cpu && idle_cpu(cpu))
+ return cpu;
+
+ /*
+ * If the task is going to be woken-up on the cpu where it previously
+ * ran and if it is currently idle, then it the right target.
+ */
+ if (target == prev_cpu && idle_cpu(prev_cpu))
+ return prev_cpu;
+
+ /*
+ * Otherwise, iterate the domains and find an elegible idle cpu.
+ */
+ sd = rcu_dereference(per_cpu(sd_llc, target));
+ for_each_lower_domain(sd) {
+ sg = sd->groups;
+ do {
+ if (!cpumask_intersects(sched_group_cpus(sg),
+ tsk_cpus_allowed(p)))
+ goto next;
+
+ for_each_cpu(i, sched_group_cpus(sg)) {
+ if (!idle_cpu(i))
+ goto next;
+ }
+
+ target = cpumask_first_and(sched_group_cpus(sg),
+ tsk_cpus_allowed(p));
+ goto done;
+next:
+ sg = sg->next;
+ } while (sg != sd->groups);
+ }
+done:
+ return target;
+}
+
+/*
+ * sched_balance_self: balance the current task (running on cpu) in domains
+ * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and
+ * SD_BALANCE_EXEC.
+ *
+ * Balance, ie. select the least loaded group.
+ *
+ * Returns the target CPU number, or the same CPU if no balancing is needed.
+ *
+ * preempt must be disabled.
+ */
+static int
+select_task_rq_fair(struct task_struct *p, int sd_flag, int wake_flags)
+{
+ struct sched_domain *tmp, *affine_sd = NULL, *sd = NULL;
+ int cpu = smp_processor_id();
+ int prev_cpu = task_cpu(p);
+ int new_cpu = cpu;
+ int want_affine = 0;
+ int want_sd = 1;
+ int sync = wake_flags & WF_SYNC;
+
+ if (p->rt.nr_cpus_allowed == 1)
+ return prev_cpu;
+
+ if (sd_flag & SD_BALANCE_WAKE) {
+ if (cpumask_test_cpu(cpu, tsk_cpus_allowed(p)))
+ want_affine = 1;
+ new_cpu = prev_cpu;
+ }
+
+ rcu_read_lock();
+ for_each_domain(cpu, tmp) {
+ if (!(tmp->flags & SD_LOAD_BALANCE))
+ continue;
+
+ /*
+ * If power savings logic is enabled for a domain, see if we
+ * are not overloaded, if so, don't balance wider.
+ */
+ if (tmp->flags & (SD_POWERSAVINGS_BALANCE|SD_PREFER_LOCAL)) {
+ unsigned long power = 0;
+ unsigned long nr_running = 0;
+ unsigned long capacity;
+ int i;
+
+ for_each_cpu(i, sched_domain_span(tmp)) {
+ power += power_of(i);
+ nr_running += cpu_rq(i)->cfs.nr_running;
+ }
+
+ capacity = DIV_ROUND_CLOSEST(power, SCHED_POWER_SCALE);
+
+ if (tmp->flags & SD_POWERSAVINGS_BALANCE)
+ nr_running /= 2;
+
+ if (nr_running < capacity)
+ want_sd = 0;
+ }
+
+ /*
+ * 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))) {
+ affine_sd = tmp;
+ want_affine = 0;
+ }
+
+ if (!want_sd && !want_affine)
+ break;
+
+ if (!(tmp->flags & sd_flag))
+ continue;
+
+ if (want_sd)
+ sd = tmp;
+ }
+
+ if (affine_sd) {
+ if (cpu == prev_cpu || wake_affine(affine_sd, p, sync))
+ prev_cpu = cpu;
+
+ new_cpu = select_idle_sibling(p, prev_cpu);
+ goto unlock;
+ }
+
+ while (sd) {
+ int load_idx = sd->forkexec_idx;
+ struct sched_group *group;
+ int weight;
+
+ if (!(sd->flags & sd_flag)) {
+ sd = sd->child;
+ continue;
+ }
+
+ if (sd_flag & SD_BALANCE_WAKE)
+ load_idx = sd->wake_idx;
+
+ group = find_idlest_group(sd, p, cpu, load_idx);
+ if (!group) {
+ sd = sd->child;
+ continue;
+ }
+
+ new_cpu = find_idlest_cpu(group, p, cpu);
+ if (new_cpu == -1 || 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;
+ }
+ /* while loop will break here if sd == NULL */
+ }
+unlock:
+ rcu_read_unlock();
+
+ return new_cpu;
+}
+#endif /* CONFIG_SMP */
+
+static unsigned long
+wakeup_gran(struct sched_entity *curr, 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(curr, se);
+ if (vdiff > gran)
+ return 1;
+
+ return 0;
+}
+
+static void set_last_buddy(struct sched_entity *se)
+{
+ if (entity_is_task(se) && unlikely(task_of(se)->policy == SCHED_IDLE))
+ return;
+
+ for_each_sched_entity(se)
+ cfs_rq_of(se)->last = se;
+}
+
+static void set_next_buddy(struct sched_entity *se)
+{
+ if (entity_is_task(se) && unlikely(task_of(se)->policy == SCHED_IDLE))
+ return;
+
+ for_each_sched_entity(se)
+ 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 move_task(), 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(curr->policy == SCHED_IDLE) &&
+ likely(p->policy != SCHED_IDLE))
+ 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))
+ 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_task(curr);
+ /*
+ * 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 *p;
+ struct cfs_rq *cfs_rq = &rq->cfs;
+ struct sched_entity *se;
+
+ if (!cfs_rq->nr_running)
+ return NULL;
+
+ do {
+ se = pick_next_entity(cfs_rq);
+ set_next_entity(cfs_rq, se);
+ cfs_rq = group_cfs_rq(se);
+ } while (cfs_rq);
+
+ p = task_of(se);
+ if (hrtick_enabled(rq))
+ hrtick_start_fair(rq, p);
+
+ return p;
+}
+
+/*
+ * 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->skip_clock_update = 1;
+ }
+
+ 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:
+ */
+
+static unsigned long __read_mostly max_load_balance_interval = HZ/10;
+
+#define LBF_ALL_PINNED 0x01
+#define LBF_NEED_BREAK 0x02
+
+struct lb_env {
+ struct sched_domain *sd;
+
+ int src_cpu;
+ struct rq *src_rq;
+
+ int dst_cpu;
+ struct rq *dst_rq;
+
+ enum cpu_idle_type idle;
+ long load_move;
+ unsigned int flags;
+
+ unsigned int loop;
+ unsigned int loop_break;
+ unsigned int loop_max;
+};
+
+/*
+ * move_task - move a task from one runqueue to another runqueue.
+ * Both runqueues must be locked.
+ */
+static void move_task(struct task_struct *p, struct lb_env *env)
+{
+ deactivate_task(env->src_rq, p, 0);
+ set_task_cpu(p, env->dst_cpu);
+ activate_task(env->dst_rq, p, 0);
+ check_preempt_curr(env->dst_rq, p, 0);
+}
+
+/*
+ * Is this task likely cache-hot:
+ */
+static int
+task_hot(struct task_struct *p, u64 now, struct sched_domain *sd)
+{
+ s64 delta;
+
+ if (p->sched_class != &fair_sched_class)
+ return 0;
+
+ if (unlikely(p->policy == SCHED_IDLE))
+ return 0;
+
+ /*
+ * Buddy candidates are cache hot:
+ */
+ if (sched_feat(CACHE_HOT_BUDDY) && this_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 = now - p->se.exec_start;
+
+ return delta < (s64)sysctl_sched_migration_cost;
+}
+
+/*
+ * 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 = 0;
+ /*
+ * We do not migrate tasks that are:
+ * 1) running (obviously), or
+ * 2) cannot be migrated to this CPU due to cpus_allowed, or
+ * 3) are cache-hot on their current CPU.
+ */
+ if (!cpumask_test_cpu(env->dst_cpu, tsk_cpus_allowed(p))) {
+ schedstat_inc(p, se.statistics.nr_failed_migrations_affine);
+ return 0;
+ }
+ 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) task is cache cold, or
+ * 2) too many balance attempts have failed.
+ */
+
+ tsk_cache_hot = task_hot(p, env->src_rq->clock_task, env->sd);
+ if (!tsk_cache_hot ||
+ env->sd->nr_balance_failed > env->sd->cache_nice_tries) {
+#ifdef CONFIG_SCHEDSTATS
+ if (tsk_cache_hot) {
+ schedstat_inc(env->sd, lb_hot_gained[env->idle]);
+ schedstat_inc(p, se.statistics.nr_forced_migrations);
+ }
+#endif
+ return 1;
+ }
+
+ if (tsk_cache_hot) {
+ schedstat_inc(p, se.statistics.nr_failed_migrations_hot);
+ return 0;
+ }
+ return 1;
+}
+
+/*
+ * move_one_task tries to move exactly one task from busiest to this_rq, as
+ * part of active balancing operations within "domain".
+ * Returns 1 if successful and 0 otherwise.
+ *
+ * Called with both runqueues locked.
+ */
+static int move_one_task(struct lb_env *env)
+{
+ struct task_struct *p, *n;
+
+ list_for_each_entry_safe(p, n, &env->src_rq->cfs_tasks, se.group_node) {
+ if (throttled_lb_pair(task_group(p), env->src_rq->cpu, env->dst_cpu))
+ continue;
+
+ if (!can_migrate_task(p, env))
+ continue;
+
+ move_task(p, env);
+ /*
+ * Right now, this is only the second place move_task()
+ * is called, so we can safely collect move_task()
+ * stats here rather than inside move_task().
+ */
+ schedstat_inc(env->sd, lb_gained[env->idle]);
+ return 1;
+ }
+ return 0;
+}
+
+static unsigned long task_h_load(struct task_struct *p);
+
+static const unsigned int sched_nr_migrate_break = 32;
+
+/*
+ * move_tasks tries to move up to load_move weighted load from busiest to
+ * this_rq, as part of a balancing operation within domain "sd".
+ * Returns 1 if successful and 0 otherwise.
+ *
+ * Called with both runqueues locked.
+ */
+static int move_tasks(struct lb_env *env)
+{
+ struct list_head *tasks = &env->src_rq->cfs_tasks;
+ struct task_struct *p;
+ unsigned long load;
+ int pulled = 0;
+
+ if (env->load_move <= 0)
+ return 0;
+
+ while (!list_empty(tasks)) {
+ p = list_first_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 (throttled_lb_pair(task_group(p), env->src_cpu, env->dst_cpu))
+ goto next;
+
+ load = task_h_load(p);
+
+ if (sched_feat(LB_MIN) && load < 16 && !env->sd->nr_balance_failed)
+ goto next;
+
+ if ((load / 2) > env->load_move)
+ goto next;
+
+ if (!can_migrate_task(p, env))
+ goto next;
+
+ move_task(p, env);
+ pulled++;
+ env->load_move -= load;
+
+#ifdef CONFIG_PREEMPT
+ /*
+ * NEWIDLE balancing is a source of latency, so preemptible
+ * kernels will stop after the first task is pulled to minimize
+ * the critical section.
+ */
+ if (env->idle == CPU_NEWLY_IDLE)
+ break;
+#endif
+
+ /*
+ * We only want to steal up to the prescribed amount of
+ * weighted load.
+ */
+ if (env->load_move <= 0)
+ break;
+
+ continue;
+next:
+ list_move_tail(&p->se.group_node, tasks);
+ }
+
+ /*
+ * Right now, this is one of only two places move_task() is called,
+ * so we can safely collect move_task() stats here rather than
+ * inside move_task().
+ */
+ schedstat_add(env->sd, lb_gained[env->idle], pulled);
+
+ return pulled;
+}
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+/*
+ * update tg->load_weight by folding this cpu's load_avg
+ */
+static int update_shares_cpu(struct task_group *tg, int cpu)
+{
+ struct cfs_rq *cfs_rq;
+ unsigned long flags;
+ struct rq *rq;
+
+ if (!tg->se[cpu])
+ return 0;
+
+ rq = cpu_rq(cpu);
+ cfs_rq = tg->cfs_rq[cpu];
+
+ raw_spin_lock_irqsave(&rq->lock, flags);
+
+ update_rq_clock(rq);
+ update_cfs_load(cfs_rq, 1);
+
+ /*
+ * We need to update shares after updating tg->load_weight in
+ * order to adjust the weight of groups with long running tasks.
+ */
+ update_cfs_shares(cfs_rq);
+
+ raw_spin_unlock_irqrestore(&rq->lock, flags);
+
+ return 0;
+}
+
+static void update_shares(int cpu)
+{
+ struct cfs_rq *cfs_rq;
+ struct rq *rq = cpu_rq(cpu);
+
+ rcu_read_lock();
+ /*
+ * Iterates the task_group tree in a bottom up fashion, see
+ * list_add_leaf_cfs_rq() for details.
+ */
+ for_each_leaf_cfs_rq(rq, cfs_rq) {
+ /* throttled entities do not contribute to load */
+ if (throttled_hierarchy(cfs_rq))
+ continue;
+
+ update_shares_cpu(cfs_rq->tg, cpu);
+ }
+ rcu_read_unlock();
+}
+
+/*
+ * Compute the cpu's hierarchical load factor for each task group.
+ * 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 int tg_load_down(struct task_group *tg, void *data)
+{
+ unsigned long load;
+ long cpu = (long)data;
+
+ if (!tg->parent) {
+ load = cpu_rq(cpu)->load.weight;
+ } else {
+ load = tg->parent->cfs_rq[cpu]->h_load;
+ load *= tg->se[cpu]->load.weight;
+ load /= tg->parent->cfs_rq[cpu]->load.weight + 1;
+ }
+
+ tg->cfs_rq[cpu]->h_load = load;
+
+ return 0;
+}
+
+static void update_h_load(long cpu)
+{
+ rcu_read_lock();
+ walk_tg_tree(tg_load_down, tg_nop, (void *)cpu);
+ rcu_read_unlock();
+}
+
+static unsigned long task_h_load(struct task_struct *p)
+{
+ struct cfs_rq *cfs_rq = task_cfs_rq(p);
+ unsigned long load;
+
+ load = p->se.load.weight;
+ load = div_u64(load * cfs_rq->h_load, cfs_rq->load.weight + 1);
+
+ return load;
+}
+#else
+static inline void update_shares(int cpu)
+{
+}
+
+static inline void update_h_load(long cpu)
+{
+}
+
+static unsigned long task_h_load(struct task_struct *p)
+{
+ return p->se.load.weight;
+}
+#endif
+
+/********** Helpers for find_busiest_group ************************/
+/*
+ * 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 *this; /* Local group in this sd */
+ unsigned long total_load; /* Total load of all groups in sd */
+ unsigned long total_pwr; /* Total power of all groups in sd */
+ unsigned long avg_load; /* Average load across all groups in sd */
+
+ /** Statistics of this group */
+ unsigned long this_load;
+ unsigned long this_load_per_task;
+ unsigned long this_nr_running;
+ unsigned long this_has_capacity;
+ unsigned int this_idle_cpus;
+
+ /* Statistics of the busiest group */
+ unsigned int busiest_idle_cpus;
+ unsigned long max_load;
+ unsigned long busiest_load_per_task;
+ unsigned long busiest_nr_running;
+ unsigned long busiest_group_capacity;
+ unsigned long busiest_has_capacity;
+ unsigned int busiest_group_weight;
+
+ int group_imb; /* Is there imbalance in this sd */
+#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
+ int power_savings_balance; /* Is powersave balance needed for this sd */
+ struct sched_group *group_min; /* Least loaded group in sd */
+ struct sched_group *group_leader; /* Group which relieves group_min */
+ unsigned long min_load_per_task; /* load_per_task in group_min */
+ unsigned long leader_nr_running; /* Nr running of group_leader */
+ unsigned long min_nr_running; /* Nr running of group_min */
+#endif
+};
+
+/*
+ * 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 sum_nr_running; /* Nr tasks running in the group */
+ unsigned long sum_weighted_load; /* Weighted load of group's tasks */
+ unsigned long group_capacity;
+ unsigned long idle_cpus;
+ unsigned long group_weight;
+ int group_imb; /* Is there an imbalance in the group ? */
+ int group_has_capacity; /* Is there extra capacity in the group? */
+};
+
+/**
+ * get_sd_load_idx - Obtain the load index for a given sched domain.
+ * @sd: The sched_domain whose load_idx is to be obtained.
+ * @idle: The Idle status of the CPU for whose sd load_icx is obtained.
+ */
+static inline int get_sd_load_idx(struct sched_domain *sd,
+ enum cpu_idle_type idle)
+{
+ int load_idx;
+
+ switch (idle) {
+ case CPU_NOT_IDLE:
+ load_idx = sd->busy_idx;
+ break;
+
+ case CPU_NEWLY_IDLE:
+ load_idx = sd->newidle_idx;
+ break;
+ default:
+ load_idx = sd->idle_idx;
+ break;
+ }
+
+ return load_idx;
+}
+
+
+#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
+/**
+ * init_sd_power_savings_stats - Initialize power savings statistics for
+ * the given sched_domain, during load balancing.
+ *
+ * @sd: Sched domain whose power-savings statistics are to be initialized.
+ * @sds: Variable containing the statistics for sd.
+ * @idle: Idle status of the CPU at which we're performing load-balancing.
+ */
+static inline void init_sd_power_savings_stats(struct sched_domain *sd,
+ struct sd_lb_stats *sds, enum cpu_idle_type idle)
+{
+ /*
+ * Busy processors will not participate in power savings
+ * balance.
+ */
+ if (idle == CPU_NOT_IDLE || !(sd->flags & SD_POWERSAVINGS_BALANCE))
+ sds->power_savings_balance = 0;
+ else {
+ sds->power_savings_balance = 1;
+ sds->min_nr_running = ULONG_MAX;
+ sds->leader_nr_running = 0;
+ }
+}
+
+/**
+ * update_sd_power_savings_stats - Update the power saving stats for a
+ * sched_domain while performing load balancing.
+ *
+ * @group: sched_group belonging to the sched_domain under consideration.
+ * @sds: Variable containing the statistics of the sched_domain
+ * @local_group: Does group contain the CPU for which we're performing
+ * load balancing ?
+ * @sgs: Variable containing the statistics of the group.
+ */
+static inline void update_sd_power_savings_stats(struct sched_group *group,
+ struct sd_lb_stats *sds, int local_group, struct sg_lb_stats *sgs)
+{
+
+ if (!sds->power_savings_balance)
+ return;
+
+ /*
+ * If the local group is idle or completely loaded
+ * no need to do power savings balance at this domain
+ */
+ if (local_group && (sds->this_nr_running >= sgs->group_capacity ||
+ !sds->this_nr_running))
+ sds->power_savings_balance = 0;
+
+ /*
+ * If a group is already running at full capacity or idle,
+ * don't include that group in power savings calculations
+ */
+ if (!sds->power_savings_balance ||
+ sgs->sum_nr_running >= sgs->group_capacity ||
+ !sgs->sum_nr_running)
+ return;
+
+ /*
+ * Calculate the group which has the least non-idle load.
+ * This is the group from where we need to pick up the load
+ * for saving power
+ */
+ if ((sgs->sum_nr_running < sds->min_nr_running) ||
+ (sgs->sum_nr_running == sds->min_nr_running &&
+ group_first_cpu(group) > group_first_cpu(sds->group_min))) {
+ sds->group_min = group;
+ sds->min_nr_running = sgs->sum_nr_running;
+ sds->min_load_per_task = sgs->sum_weighted_load /
+ sgs->sum_nr_running;
+ }
+
+ /*
+ * Calculate the group which is almost near its
+ * capacity but still has some space to pick up some load
+ * from other group and save more power
+ */
+ if (sgs->sum_nr_running + 1 > sgs->group_capacity)
+ return;
+
+ if (sgs->sum_nr_running > sds->leader_nr_running ||
+ (sgs->sum_nr_running == sds->leader_nr_running &&
+ group_first_cpu(group) < group_first_cpu(sds->group_leader))) {
+ sds->group_leader = group;
+ sds->leader_nr_running = sgs->sum_nr_running;
+ }
+}
+
+/**
+ * check_power_save_busiest_group - see if there is potential for some power-savings balance
+ * @sds: Variable containing the statistics of the sched_domain
+ * under consideration.
+ * @this_cpu: Cpu at which we're currently performing load-balancing.
+ * @imbalance: Variable to store the imbalance.
+ *
+ * Description:
+ * Check if we have potential to perform some power-savings balance.
+ * If yes, set the busiest group to be the least loaded group in the
+ * sched_domain, so that it's CPUs can be put to idle.
+ *
+ * Returns 1 if there is potential to perform power-savings balance.
+ * Else returns 0.
+ */
+static inline int check_power_save_busiest_group(struct sd_lb_stats *sds,
+ int this_cpu, unsigned long *imbalance)
+{
+ if (!sds->power_savings_balance)
+ return 0;
+
+ if (sds->this != sds->group_leader ||
+ sds->group_leader == sds->group_min)
+ return 0;
+
+ *imbalance = sds->min_load_per_task;
+ sds->busiest = sds->group_min;
+
+ return 1;
+
+}
+#else /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
+static inline void init_sd_power_savings_stats(struct sched_domain *sd,
+ struct sd_lb_stats *sds, enum cpu_idle_type idle)
+{
+ return;
+}
+
+static inline void update_sd_power_savings_stats(struct sched_group *group,
+ struct sd_lb_stats *sds, int local_group, struct sg_lb_stats *sgs)
+{
+ return;
+}
+
+static inline int check_power_save_busiest_group(struct sd_lb_stats *sds,
+ int this_cpu, unsigned long *imbalance)
+{
+ return 0;
+}
+#endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
+
+
+unsigned long default_scale_freq_power(struct sched_domain *sd, int cpu)
+{
+ return SCHED_POWER_SCALE;
+}
+
+unsigned long __weak arch_scale_freq_power(struct sched_domain *sd, int cpu)
+{
+ return default_scale_freq_power(sd, cpu);
+}
+
+unsigned long default_scale_smt_power(struct sched_domain *sd, int cpu)
+{
+ unsigned long weight = sd->span_weight;
+ unsigned long smt_gain = sd->smt_gain;
+
+ smt_gain /= weight;
+
+ return smt_gain;
+}
+
+unsigned long __weak arch_scale_smt_power(struct sched_domain *sd, int cpu)
+{
+ return default_scale_smt_power(sd, cpu);
+}
+
+unsigned long scale_rt_power(int cpu)
+{
+ struct rq *rq = cpu_rq(cpu);
+ u64 total, available;
+
+ total = sched_avg_period() + (rq->clock - rq->age_stamp);
+
+ if (unlikely(total < rq->rt_avg)) {
+ /* Ensures that power won't end up being negative */
+ available = 0;
+ } else {
+ available = total - rq->rt_avg;
+ }
+
+ if (unlikely((s64)total < SCHED_POWER_SCALE))
+ total = SCHED_POWER_SCALE;
+
+ total >>= SCHED_POWER_SHIFT;
+
+ return div_u64(available, total);
+}
+
+static void update_cpu_power(struct sched_domain *sd, int cpu)
+{
+ unsigned long weight = sd->span_weight;
+ unsigned long power = SCHED_POWER_SCALE;
+ struct sched_group *sdg = sd->groups;
+
+ if ((sd->flags & SD_SHARE_CPUPOWER) && weight > 1) {
+ if (sched_feat(ARCH_POWER))
+ power *= arch_scale_smt_power(sd, cpu);
+ else
+ power *= default_scale_smt_power(sd, cpu);
+
+ power >>= SCHED_POWER_SHIFT;
+ }
+
+ sdg->sgp->power_orig = power;
+
+ if (sched_feat(ARCH_POWER))
+ power *= arch_scale_freq_power(sd, cpu);
+ else
+ power *= default_scale_freq_power(sd, cpu);
+
+ power >>= SCHED_POWER_SHIFT;
+
+ power *= scale_rt_power(cpu);
+ power >>= SCHED_POWER_SHIFT;
+
+ if (!power)
+ power = 1;
+
+ cpu_rq(cpu)->cpu_power = power;
+ sdg->sgp->power = power;
+}
+
+void update_group_power(struct sched_domain *sd, int cpu)
+{
+ struct sched_domain *child = sd->child;
+ struct sched_group *group, *sdg = sd->groups;
+ unsigned long power;
+ unsigned long interval;
+
+ interval = msecs_to_jiffies(sd->balance_interval);
+ interval = clamp(interval, 1UL, max_load_balance_interval);
+ sdg->sgp->next_update = jiffies + interval;
+
+ if (!child) {
+ update_cpu_power(sd, cpu);
+ return;
+ }
+
+ power = 0;
+
+ group = child->groups;
+ do {
+ power += group->sgp->power;
+ group = group->next;
+ } while (group != child->groups);
+
+ sdg->sgp->power = power;
+}
+
+/*
+ * Try and fix up capacity for tiny siblings, this is needed when
+ * things like SD_ASYM_PACKING need f_b_g to select another sibling
+ * which on its own isn't powerful enough.
+ *
+ * See update_sd_pick_busiest() and check_asym_packing().
+ */
+static inline int
+fix_small_capacity(struct sched_domain *sd, struct sched_group *group)
+{
+ /*
+ * Only siblings can have significantly less than SCHED_POWER_SCALE
+ */
+ if (!(sd->flags & SD_SHARE_CPUPOWER))
+ return 0;
+
+ /*
+ * If ~90% of the cpu_power is still there, we're good.
+ */
+ if (group->sgp->power * 32 > group->sgp->power_orig * 29)
+ return 1;
+
+ return 0;
+}
+
+/**
+ * update_sg_lb_stats - Update sched_group's statistics for load balancing.
+ * @sd: The sched_domain whose statistics are to be updated.
+ * @group: sched_group whose statistics are to be updated.
+ * @this_cpu: Cpu for which load balance is currently performed.
+ * @idle: Idle status of this_cpu
+ * @load_idx: Load index of sched_domain of this_cpu for load calc.
+ * @local_group: Does group contain this_cpu.
+ * @cpus: Set of cpus considered for load balancing.
+ * @balance: Should we balance.
+ * @sgs: variable to hold the statistics for this group.
+ */
+static inline void update_sg_lb_stats(struct sched_domain *sd,
+ struct sched_group *group, int this_cpu,
+ enum cpu_idle_type idle, int load_idx,
+ int local_group, const struct cpumask *cpus,
+ int *balance, struct sg_lb_stats *sgs)
+{
+ unsigned long load, max_cpu_load, min_cpu_load, max_nr_running;
+ int i;
+ unsigned int balance_cpu = -1, first_idle_cpu = 0;
+ unsigned long avg_load_per_task = 0;
+
+ if (local_group)
+ balance_cpu = group_first_cpu(group);
+
+ /* Tally up the load of all CPUs in the group */
+ max_cpu_load = 0;
+ min_cpu_load = ~0UL;
+ max_nr_running = 0;
+
+ for_each_cpu_and(i, sched_group_cpus(group), cpus) {
+ struct rq *rq = cpu_rq(i);
+
+ /* Bias balancing toward cpus of our domain */
+ if (local_group) {
+ if (idle_cpu(i) && !first_idle_cpu) {
+ first_idle_cpu = 1;
+ balance_cpu = i;
+ }
+
+ load = target_load(i, load_idx);
+ } else {
+ load = source_load(i, load_idx);
+ if (load > max_cpu_load) {
+ max_cpu_load = load;
+ max_nr_running = rq->nr_running;
+ }
+ if (min_cpu_load > load)
+ min_cpu_load = load;
+ }
+
+ sgs->group_load += load;
+ sgs->sum_nr_running += rq->nr_running;
+ sgs->sum_weighted_load += weighted_cpuload(i);
+ if (idle_cpu(i))
+ sgs->idle_cpus++;
+ }
+
+ /*
+ * First idle cpu or the first cpu(busiest) in this sched group
+ * is eligible for doing load balancing at this and above
+ * domains. In the newly idle case, we will allow all the cpu's
+ * to do the newly idle load balance.
+ */
+ if (local_group) {
+ if (idle != CPU_NEWLY_IDLE) {
+ if (balance_cpu != this_cpu) {
+ *balance = 0;
+ return;
+ }
+ update_group_power(sd, this_cpu);
+ } else if (time_after_eq(jiffies, group->sgp->next_update))
+ update_group_power(sd, this_cpu);
+ }
+
+ /* Adjust by relative CPU power of the group */
+ sgs->avg_load = (sgs->group_load*SCHED_POWER_SCALE) / group->sgp->power;
+
+ /*
+ * Consider the group unbalanced when the imbalance is larger
+ * than the average weight of a task.
+ *
+ * APZ: with cgroup the avg task weight can vary wildly and
+ * might not be a suitable number - should we keep a
+ * normalized nr_running number somewhere that negates
+ * the hierarchy?
+ */
+ if (sgs->sum_nr_running)
+ avg_load_per_task = sgs->sum_weighted_load / sgs->sum_nr_running;
+
+ if ((max_cpu_load - min_cpu_load) >= avg_load_per_task && max_nr_running > 1)
+ sgs->group_imb = 1;
+
+ sgs->group_capacity = DIV_ROUND_CLOSEST(group->sgp->power,
+ SCHED_POWER_SCALE);
+ if (!sgs->group_capacity)
+ sgs->group_capacity = fix_small_capacity(sd, group);
+ sgs->group_weight = group->group_weight;
+
+ if (sgs->group_capacity > sgs->sum_nr_running)
+ sgs->group_has_capacity = 1;
+}
+
+/**
+ * update_sd_pick_busiest - return 1 on busiest group
+ * @sd: sched_domain whose statistics are to be checked
+ * @sds: sched_domain statistics
+ * @sg: sched_group candidate to be checked for being the busiest
+ * @sgs: sched_group statistics
+ * @this_cpu: the current cpu
+ *
+ * Determine if @sg is a busier group than the previously selected
+ * busiest group.
+ */
+static bool update_sd_pick_busiest(struct sched_domain *sd,
+ struct sd_lb_stats *sds,
+ struct sched_group *sg,
+ struct sg_lb_stats *sgs,
+ int this_cpu)
+{
+ if (sgs->avg_load <= sds->max_load)
+ return false;
+
+ if (sgs->sum_nr_running > sgs->group_capacity)
+ return true;
+
+ if (sgs->group_imb)
+ return true;
+
+ /*
+ * ASYM_PACKING needs to move all the work to the lowest
+ * numbered CPUs in the group, therefore mark all groups
+ * higher than ourself as busy.
+ */
+ if ((sd->flags & SD_ASYM_PACKING) && sgs->sum_nr_running &&
+ this_cpu < group_first_cpu(sg)) {
+ if (!sds->busiest)
+ return true;
+
+ if (group_first_cpu(sds->busiest) > group_first_cpu(sg))
+ return true;
+ }
+
+ return false;
+}
+
+/**
+ * update_sd_lb_stats - Update sched_domain's statistics for load balancing.
+ * @sd: sched_domain whose statistics are to be updated.
+ * @this_cpu: Cpu for which load balance is currently performed.
+ * @idle: Idle status of this_cpu
+ * @cpus: Set of cpus considered for load balancing.
+ * @balance: Should we balance.
+ * @sds: variable to hold the statistics for this sched_domain.
+ */
+static inline void update_sd_lb_stats(struct sched_domain *sd, int this_cpu,
+ enum cpu_idle_type idle, const struct cpumask *cpus,
+ int *balance, struct sd_lb_stats *sds)
+{
+ struct sched_domain *child = sd->child;
+ struct sched_group *sg = sd->groups;
+ struct sg_lb_stats sgs;
+ int load_idx, prefer_sibling = 0;
+
+ if (child && child->flags & SD_PREFER_SIBLING)
+ prefer_sibling = 1;
+
+ init_sd_power_savings_stats(sd, sds, idle);
+ load_idx = get_sd_load_idx(sd, idle);
+
+ do {
+ int local_group;
+
+ local_group = cpumask_test_cpu(this_cpu, sched_group_cpus(sg));
+ memset(&sgs, 0, sizeof(sgs));
+ update_sg_lb_stats(sd, sg, this_cpu, idle, load_idx,
+ local_group, cpus, balance, &sgs);
+
+ if (local_group && !(*balance))
+ return;
+
+ sds->total_load += sgs.group_load;
+ sds->total_pwr += sg->sgp->power;
+
+ /*
+ * In case the child domain prefers tasks go to siblings
+ * first, lower the sg capacity to one 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, i.e. nr_running < group_capacity. 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 && !local_group && sds->this_has_capacity)
+ sgs.group_capacity = min(sgs.group_capacity, 1UL);
+
+ if (local_group) {
+ sds->this_load = sgs.avg_load;
+ sds->this = sg;
+ sds->this_nr_running = sgs.sum_nr_running;
+ sds->this_load_per_task = sgs.sum_weighted_load;
+ sds->this_has_capacity = sgs.group_has_capacity;
+ sds->this_idle_cpus = sgs.idle_cpus;
+ } else if (update_sd_pick_busiest(sd, sds, sg, &sgs, this_cpu)) {
+ sds->max_load = sgs.avg_load;
+ sds->busiest = sg;
+ sds->busiest_nr_running = sgs.sum_nr_running;
+ sds->busiest_idle_cpus = sgs.idle_cpus;
+ sds->busiest_group_capacity = sgs.group_capacity;
+ sds->busiest_load_per_task = sgs.sum_weighted_load;
+ sds->busiest_has_capacity = sgs.group_has_capacity;
+ sds->busiest_group_weight = sgs.group_weight;
+ sds->group_imb = sgs.group_imb;
+ }
+
+ update_sd_power_savings_stats(sg, sds, local_group, &sgs);
+ sg = sg->next;
+ } while (sg != sd->groups);
+}
+
+/**
+ * check_asym_packing - Check to see if the group is packed into the
+ * sched doman.
+ *
+ * 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.
+ *
+ * Returns 1 when packing is required and a task should be moved to
+ * this CPU. The amount of the imbalance is returned in *imbalance.
+ *
+ * @sd: The sched_domain whose packing is to be checked.
+ * @sds: Statistics of the sched_domain which is to be packed
+ * @this_cpu: The cpu at whose sched_domain we're performing load-balance.
+ * @imbalance: returns amount of imbalanced due to packing.
+ */
+static int check_asym_packing(struct sched_domain *sd,
+ struct sd_lb_stats *sds,
+ int this_cpu, unsigned long *imbalance)
+{
+ int busiest_cpu;
+
+ if (!(sd->flags & SD_ASYM_PACKING))
+ return 0;
+
+ if (!sds->busiest)
+ return 0;
+
+ busiest_cpu = group_first_cpu(sds->busiest);
+ if (this_cpu > busiest_cpu)
+ return 0;
+
+ *imbalance = DIV_ROUND_CLOSEST(sds->max_load * sds->busiest->sgp->power,
+ SCHED_POWER_SCALE);
+ return 1;
+}
+
+/**
+ * fix_small_imbalance - Calculate the minor imbalance that exists
+ * amongst the groups of a sched_domain, during
+ * load balancing.
+ * @sds: Statistics of the sched_domain whose imbalance is to be calculated.
+ * @this_cpu: The cpu at whose sched_domain we're performing load-balance.
+ * @imbalance: Variable to store the imbalance.
+ */
+static inline void fix_small_imbalance(struct sd_lb_stats *sds,
+ int this_cpu, unsigned long *imbalance)
+{
+ unsigned long tmp, pwr_now = 0, pwr_move = 0;
+ unsigned int imbn = 2;
+ unsigned long scaled_busy_load_per_task;
+
+ if (sds->this_nr_running) {
+ sds->this_load_per_task /= sds->this_nr_running;
+ if (sds->busiest_load_per_task >
+ sds->this_load_per_task)
+ imbn = 1;
+ } else
+ sds->this_load_per_task =
+ cpu_avg_load_per_task(this_cpu);
+
+ scaled_busy_load_per_task = sds->busiest_load_per_task
+ * SCHED_POWER_SCALE;
+ scaled_busy_load_per_task /= sds->busiest->sgp->power;
+
+ if (sds->max_load - sds->this_load + scaled_busy_load_per_task >=
+ (scaled_busy_load_per_task * imbn)) {
+ *imbalance = sds->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 power used by
+ * moving them.
+ */
+
+ pwr_now += sds->busiest->sgp->power *
+ min(sds->busiest_load_per_task, sds->max_load);
+ pwr_now += sds->this->sgp->power *
+ min(sds->this_load_per_task, sds->this_load);
+ pwr_now /= SCHED_POWER_SCALE;
+
+ /* Amount of load we'd subtract */
+ tmp = (sds->busiest_load_per_task * SCHED_POWER_SCALE) /
+ sds->busiest->sgp->power;
+ if (sds->max_load > tmp)
+ pwr_move += sds->busiest->sgp->power *
+ min(sds->busiest_load_per_task, sds->max_load - tmp);
+
+ /* Amount of load we'd add */
+ if (sds->max_load * sds->busiest->sgp->power <
+ sds->busiest_load_per_task * SCHED_POWER_SCALE)
+ tmp = (sds->max_load * sds->busiest->sgp->power) /
+ sds->this->sgp->power;
+ else
+ tmp = (sds->busiest_load_per_task * SCHED_POWER_SCALE) /
+ sds->this->sgp->power;
+ pwr_move += sds->this->sgp->power *
+ min(sds->this_load_per_task, sds->this_load + tmp);
+ pwr_move /= SCHED_POWER_SCALE;
+
+ /* Move if we gain throughput */
+ if (pwr_move > pwr_now)
+ *imbalance = sds->busiest_load_per_task;
+}
+
+/**
+ * calculate_imbalance - Calculate the amount of imbalance present within the
+ * groups of a given sched_domain during load balance.
+ * @sds: statistics of the sched_domain whose imbalance is to be calculated.
+ * @this_cpu: Cpu for which currently load balance is being performed.
+ * @imbalance: The variable to store the imbalance.
+ */
+static inline void calculate_imbalance(struct sd_lb_stats *sds, int this_cpu,
+ unsigned long *imbalance)
+{
+ unsigned long max_pull, load_above_capacity = ~0UL;
+
+ sds->busiest_load_per_task /= sds->busiest_nr_running;
+ if (sds->group_imb) {
+ sds->busiest_load_per_task =
+ min(sds->busiest_load_per_task, sds->avg_load);
+ }
+
+ /*
+ * In the presence of smp nice balancing, certain scenarios can have
+ * max load less than avg load(as we skip the groups at or below
+ * its cpu_power, while calculating max_load..)
+ */
+ if (sds->max_load < sds->avg_load) {
+ *imbalance = 0;
+ return fix_small_imbalance(sds, this_cpu, imbalance);
+ }
+
+ if (!sds->group_imb) {
+ /*
+ * Don't want to pull so many tasks that a group would go idle.
+ */
+ load_above_capacity = (sds->busiest_nr_running -
+ sds->busiest_group_capacity);
+
+ load_above_capacity *= (SCHED_LOAD_SCALE * SCHED_POWER_SCALE);
+
+ load_above_capacity /= sds->busiest->sgp->power;
+ }
+
+ /*
+ * 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
+ * (so that we can implement power-savings policies etc). Thus we look
+ * for the minimum possible imbalance.
+ * Be careful of negative numbers as they'll appear as very large values
+ * with unsigned longs.
+ */
+ max_pull = min(sds->max_load - sds->avg_load, load_above_capacity);
+
+ /* How much load to actually move to equalise the imbalance */
+ *imbalance = min(max_pull * sds->busiest->sgp->power,
+ (sds->avg_load - sds->this_load) * sds->this->sgp->power)
+ / SCHED_POWER_SCALE;
+
+ /*
+ * 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 (*imbalance < sds->busiest_load_per_task)
+ return fix_small_imbalance(sds, this_cpu, imbalance);
+
+}
+
+/******* find_busiest_group() helpers end here *********************/
+
+/**
+ * find_busiest_group - Returns the busiest group within the sched_domain
+ * if there is an imbalance. If there isn't an imbalance, and
+ * the user has opted for power-savings, it returns a group whose
+ * CPUs can be put to idle by rebalancing those tasks elsewhere, if
+ * such a group exists.
+ *
+ * Also calculates the amount of weighted load which should be moved
+ * to restore balance.
+ *
+ * @sd: The sched_domain whose busiest group is to be returned.
+ * @this_cpu: The cpu for which load balancing is currently being performed.
+ * @imbalance: Variable which stores amount of weighted load which should
+ * be moved to restore balance/put a group to idle.
+ * @idle: The idle status of this_cpu.
+ * @cpus: The set of CPUs under consideration for load-balancing.
+ * @balance: Pointer to a variable indicating if this_cpu
+ * is the appropriate cpu to perform load balancing at this_level.
+ *
+ * Returns: - the busiest group if imbalance exists.
+ * - If no imbalance and user has opted for power-savings balance,
+ * return the least loaded group whose CPUs can be
+ * put to idle by rebalancing its tasks onto our group.
+ */
+static struct sched_group *
+find_busiest_group(struct sched_domain *sd, int this_cpu,
+ unsigned long *imbalance, enum cpu_idle_type idle,
+ const struct cpumask *cpus, int *balance)
+{
+ struct sd_lb_stats sds;
+
+ memset(&sds, 0, sizeof(sds));
+
+ /*
+ * Compute the various statistics relavent for load balancing at
+ * this level.
+ */
+ update_sd_lb_stats(sd, this_cpu, idle, cpus, balance, &sds);
+
+ /*
+ * this_cpu is not the appropriate cpu to perform load balancing at
+ * this level.
+ */
+ if (!(*balance))
+ goto ret;
+
+ if ((idle == CPU_IDLE || idle == CPU_NEWLY_IDLE) &&
+ check_asym_packing(sd, &sds, this_cpu, imbalance))
+ return sds.busiest;
+
+ /* There is no busy sibling group to pull tasks from */
+ if (!sds.busiest || sds.busiest_nr_running == 0)
+ goto out_balanced;
+
+ sds.avg_load = (SCHED_POWER_SCALE * sds.total_load) / sds.total_pwr;
+
+ /*
+ * If the busiest group is imbalanced the below checks don't
+ * work because they assumes all things are equal, which typically
+ * isn't true due to cpus_allowed constraints and the like.
+ */
+ if (sds.group_imb)
+ goto force_balance;
+
+ /* SD_BALANCE_NEWIDLE trumps SMP nice when underutilized */
+ if (idle == CPU_NEWLY_IDLE && sds.this_has_capacity &&
+ !sds.busiest_has_capacity)
+ goto force_balance;
+
+ /*
+ * If the local group is more busy than the selected busiest group
+ * don't try and pull any tasks.
+ */
+ if (sds.this_load >= sds.max_load)
+ goto out_balanced;
+
+ /*
+ * Don't pull any tasks if this group is already above the domain
+ * average load.
+ */
+ if (sds.this_load >= sds.avg_load)
+ goto out_balanced;
+
+ if (idle == CPU_IDLE) {
+ /*
+ * This cpu is idle. If the busiest group load doesn't
+ * have more tasks than the number of available cpu's and
+ * there is no imbalance between this and busiest group
+ * wrt to idle cpu's, it is balanced.
+ */
+ if ((sds.this_idle_cpus <= sds.busiest_idle_cpus + 1) &&
+ sds.busiest_nr_running <= sds.busiest_group_weight)
+ goto out_balanced;
+ } else {
+ /*
+ * In the CPU_NEWLY_IDLE, CPU_NOT_IDLE cases, use
+ * imbalance_pct to be conservative.
+ */
+ if (100 * sds.max_load <= sd->imbalance_pct * sds.this_load)
+ goto out_balanced;
+ }
+
+force_balance:
+ /* Looks like there is an imbalance. Compute it */
+ calculate_imbalance(&sds, this_cpu, imbalance);
+ return sds.busiest;
+
+out_balanced:
+ /*
+ * There is no obvious imbalance. But check if we can do some balancing
+ * to save power.
+ */
+ if (check_power_save_busiest_group(&sds, this_cpu, imbalance))
+ return sds.busiest;
+ret:
+ *imbalance = 0;
+ return NULL;
+}
+
+/*
+ * find_busiest_queue - find the busiest runqueue among the cpus in group.
+ */
+static struct rq *
+find_busiest_queue(struct sched_domain *sd, struct sched_group *group,
+ enum cpu_idle_type idle, unsigned long imbalance,
+ const struct cpumask *cpus)
+{
+ struct rq *busiest = NULL, *rq;
+ unsigned long max_load = 0;
+ int i;
+
+ for_each_cpu(i, sched_group_cpus(group)) {
+ unsigned long power = power_of(i);
+ unsigned long capacity = DIV_ROUND_CLOSEST(power,
+ SCHED_POWER_SCALE);
+ unsigned long wl;
+
+ if (!capacity)
+ capacity = fix_small_capacity(sd, group);
+
+ if (!cpumask_test_cpu(i, cpus))
+ continue;
+
+ rq = cpu_rq(i);
+ wl = weighted_cpuload(i);
+
+ /*
+ * When comparing with imbalance, use weighted_cpuload()
+ * which is not scaled with the cpu power.
+ */
+ if (capacity && rq->nr_running == 1 && wl > imbalance)
+ continue;
+
+ /*
+ * For the load comparisons with the other cpu's, consider
+ * the weighted_cpuload() scaled with the cpu power, so that
+ * the load can be moved away from the cpu that is potentially
+ * running at a lower capacity.
+ */
+ wl = (wl * SCHED_POWER_SCALE) / power;
+
+ if (wl > max_load) {
+ max_load = wl;
+ 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
+
+/* Working cpumask for load_balance and load_balance_newidle. */
+DEFINE_PER_CPU(cpumask_var_t, load_balance_tmpmask);
+
+static int need_active_balance(struct sched_domain *sd, int idle,
+ int busiest_cpu, int this_cpu)
+{
+ if (idle == CPU_NEWLY_IDLE) {
+
+ /*
+ * ASYM_PACKING needs to force migrate tasks from busy but
+ * higher numbered CPUs in order to pack all tasks in the
+ * lowest numbered CPUs.
+ */
+ if ((sd->flags & SD_ASYM_PACKING) && busiest_cpu > this_cpu)
+ return 1;
+
+ /*
+ * The only task running in a non-idle cpu can be moved to this
+ * cpu in an attempt to completely freeup the other CPU
+ * package.
+ *
+ * The package power saving logic comes from
+ * find_busiest_group(). If there are no imbalance, then
+ * f_b_g() will return NULL. However when sched_mc={1,2} then
+ * f_b_g() will select a group from which a running task may be
+ * pulled to this cpu in order to make the other package idle.
+ * If there is no opportunity to make a package idle and if
+ * there are no imbalance, then f_b_g() will return NULL and no
+ * action will be taken in load_balance_newidle().
+ *
+ * Under normal task pull operation due to imbalance, there
+ * will be more than one task in the source run queue and
+ * move_tasks() will succeed. ld_moved will be true and this
+ * active balance code will not be triggered.
+ */
+ if (sched_mc_power_savings < POWERSAVINGS_BALANCE_WAKEUP)
+ return 0;
+ }
+
+ return unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2);
+}
+
+static int active_load_balance_cpu_stop(void *data);
+
+/*
+ * 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 *balance)
+{
+ int ld_moved, active_balance = 0;
+ struct sched_group *group;
+ unsigned long imbalance;
+ struct rq *busiest;
+ unsigned long flags;
+ struct cpumask *cpus = __get_cpu_var(load_balance_tmpmask);
+
+ struct lb_env env = {
+ .sd = sd,
+ .dst_cpu = this_cpu,
+ .dst_rq = this_rq,
+ .idle = idle,
+ .loop_break = sched_nr_migrate_break,
+ };
+
+ cpumask_copy(cpus, cpu_active_mask);
+
+ schedstat_inc(sd, lb_count[idle]);
+
+redo:
+ group = find_busiest_group(sd, this_cpu, &imbalance, idle,
+ cpus, balance);
+
+ if (*balance == 0)
+ goto out_balanced;
+
+ if (!group) {
+ schedstat_inc(sd, lb_nobusyg[idle]);
+ goto out_balanced;
+ }
+
+ busiest = find_busiest_queue(sd, group, idle, imbalance, cpus);
+ if (!busiest) {
+ schedstat_inc(sd, lb_nobusyq[idle]);
+ goto out_balanced;
+ }
+
+ BUG_ON(busiest == this_rq);
+
+ schedstat_add(sd, lb_imbalance[idle], imbalance);
+
+ 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.load_move = imbalance;
+ env.src_cpu = busiest->cpu;
+ env.src_rq = busiest;
+ env.loop_max = min_t(unsigned long, sysctl_sched_nr_migrate, busiest->nr_running);
+
+more_balance:
+ local_irq_save(flags);
+ double_rq_lock(this_rq, busiest);
+ if (!env.loop)
+ update_h_load(env.src_cpu);
+ ld_moved += move_tasks(&env);
+ double_rq_unlock(this_rq, busiest);
+ local_irq_restore(flags);
+
+ if (env.flags & LBF_NEED_BREAK) {
+ env.flags &= ~LBF_NEED_BREAK;
+ goto more_balance;
+ }
+
+ /*
+ * some other cpu did the load balance for us.
+ */
+ if (ld_moved && this_cpu != smp_processor_id())
+ resched_cpu(this_cpu);
+
+ /* All tasks on this runqueue were pinned by CPU affinity */
+ if (unlikely(env.flags & LBF_ALL_PINNED)) {
+ cpumask_clear_cpu(cpu_of(busiest), cpus);
+ if (!cpumask_empty(cpus))
+ goto redo;
+ goto out_balanced;
+ }
+ }
+
+ 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)
+ sd->nr_balance_failed++;
+
+ if (need_active_balance(sd, idle, cpu_of(busiest), this_cpu)) {
+ 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,
+ tsk_cpus_allowed(busiest->curr))) {
+ 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, reset the failure
+ * counter.
+ */
+ sd->nr_balance_failed = sd->cache_nice_tries+1;
+ }
+ } else
+ sd->nr_balance_failed = 0;
+
+ if (likely(!active_balance)) {
+ /* 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
+ * move_tasks).
+ */
+ if (sd->balance_interval < sd->max_interval)
+ sd->balance_interval *= 2;
+ }
+
+ goto out;
+
+out_balanced:
+ schedstat_inc(sd, lb_balanced[idle]);
+
+ sd->nr_balance_failed = 0;
+
+out_one_pinned:
+ /* 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;
+
+ ld_moved = 0;
+out:
+ return ld_moved;
+}
+
+/*
+ * idle_balance is called by schedule() if this_cpu is about to become
+ * idle. Attempts to pull tasks from other CPUs.
+ */
+void idle_balance(int this_cpu, struct rq *this_rq)
+{
+ struct sched_domain *sd;
+ int pulled_task = 0;
+ unsigned long next_balance = jiffies + HZ;
+
+ this_rq->idle_stamp = this_rq->clock;
+
+ if (this_rq->avg_idle < sysctl_sched_migration_cost)
+ return;
+
+ /*
+ * Drop the rq->lock, but keep IRQ/preempt disabled.
+ */
+ raw_spin_unlock(&this_rq->lock);
+
+ update_shares(this_cpu);
+ rcu_read_lock();
+ for_each_domain(this_cpu, sd) {
+ unsigned long interval;
+ int balance = 1;
+
+ if (!(sd->flags & SD_LOAD_BALANCE))
+ continue;
+
+ if (sd->flags & SD_BALANCE_NEWIDLE) {
+ /* If we've pulled tasks over stop searching: */
+ pulled_task = load_balance(this_cpu, this_rq,
+ sd, CPU_NEWLY_IDLE, &balance);
+ }
+
+ interval = msecs_to_jiffies(sd->balance_interval);
+ if (time_after(next_balance, sd->last_balance + interval))
+ next_balance = sd->last_balance + interval;
+ if (pulled_task) {
+ this_rq->idle_stamp = 0;
+ break;
+ }
+ }
+ rcu_read_unlock();
+
+ raw_spin_lock(&this_rq->lock);
+
+ if (pulled_task || time_after(jiffies, this_rq->next_balance)) {
+ /*
+ * We are going idle. next_balance may be set based on
+ * a busy processor. So reset next_balance.
+ */
+ this_rq->next_balance = next_balance;
+ }
+}
+
+/*
+ * active_load_balance_cpu_stop is run by 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;
+
+ raw_spin_lock_irq(&busiest_rq->lock);
+
+ /* 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);
+
+ /* move a task from busiest_rq to target_rq */
+ double_lock_balance(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,
+ };
+
+ schedstat_inc(sd, alb_count);
+
+ if (move_one_task(&env))
+ schedstat_inc(sd, alb_pushed);
+ else
+ schedstat_inc(sd, alb_failed);
+ }
+ rcu_read_unlock();
+ double_unlock_balance(busiest_rq, target_rq);
+out_unlock:
+ busiest_rq->active_balance = 0;
+ raw_spin_unlock_irq(&busiest_rq->lock);
+ return 0;
+}
+
+#ifdef CONFIG_NO_HZ
+/*
+ * 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.
+ */
+static struct {
+ cpumask_var_t idle_cpus_mask;
+ atomic_t nr_cpus;
+ unsigned long next_balance; /* in jiffy units */
+} nohz ____cacheline_aligned;
+
+#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
+/**
+ * lowest_flag_domain - Return lowest sched_domain containing flag.
+ * @cpu: The cpu whose lowest level of sched domain is to
+ * be returned.
+ * @flag: The flag to check for the lowest sched_domain
+ * for the given cpu.
+ *
+ * Returns the lowest sched_domain of a cpu which contains the given flag.
+ */
+static inline struct sched_domain *lowest_flag_domain(int cpu, int flag)
+{
+ struct sched_domain *sd;
+
+ for_each_domain(cpu, sd)
+ if (sd->flags & flag)
+ break;
+
+ return sd;
+}
+
+/**
+ * for_each_flag_domain - Iterates over sched_domains containing the flag.
+ * @cpu: The cpu whose domains we're iterating over.
+ * @sd: variable holding the value of the power_savings_sd
+ * for cpu.
+ * @flag: The flag to filter the sched_domains to be iterated.
+ *
+ * Iterates over all the scheduler domains for a given cpu that has the 'flag'
+ * set, starting from the lowest sched_domain to the highest.
+ */
+#define for_each_flag_domain(cpu, sd, flag) \
+ for (sd = lowest_flag_domain(cpu, flag); \
+ (sd && (sd->flags & flag)); sd = sd->parent)
+
+/**
+ * find_new_ilb - Finds the optimum idle load balancer for nomination.
+ * @cpu: The cpu which is nominating a new idle_load_balancer.
+ *
+ * Returns: Returns the id of the idle load balancer if it exists,
+ * Else, returns >= nr_cpu_ids.
+ *
+ * This algorithm picks the idle load balancer such that it belongs to a
+ * semi-idle powersavings sched_domain. The idea is to try and avoid
+ * completely idle packages/cores just for the purpose of idle load balancing
+ * when there are other idle cpu's which are better suited for that job.
+ */
+static int find_new_ilb(int cpu)
+{
+ int ilb = cpumask_first(nohz.idle_cpus_mask);
+ struct sched_group *ilbg;
+ struct sched_domain *sd;
+
+ /*
+ * Have idle load balancer selection from semi-idle packages only
+ * when power-aware load balancing is enabled
+ */
+ if (!(sched_smt_power_savings || sched_mc_power_savings))
+ goto out_done;
+
+ /*
+ * Optimize for the case when we have no idle CPUs or only one
+ * idle CPU. Don't walk the sched_domain hierarchy in such cases
+ */
+ if (cpumask_weight(nohz.idle_cpus_mask) < 2)
+ goto out_done;
+
+ rcu_read_lock();
+ for_each_flag_domain(cpu, sd, SD_POWERSAVINGS_BALANCE) {
+ ilbg = sd->groups;
+
+ do {
+ if (ilbg->group_weight !=
+ atomic_read(&ilbg->sgp->nr_busy_cpus)) {
+ ilb = cpumask_first_and(nohz.idle_cpus_mask,
+ sched_group_cpus(ilbg));
+ goto unlock;
+ }
+
+ ilbg = ilbg->next;
+
+ } while (ilbg != sd->groups);
+ }
+unlock:
+ rcu_read_unlock();
+
+out_done:
+ if (ilb < nr_cpu_ids && idle_cpu(ilb))
+ return ilb;
+
+ return nr_cpu_ids;
+}
+#else /* (CONFIG_SCHED_MC || CONFIG_SCHED_SMT) */
+static inline int find_new_ilb(int call_cpu)
+{
+ return nr_cpu_ids;
+}
+#endif
+
+/*
+ * Kick a CPU to do the nohz balancing, if it is time for it. We pick the
+ * nohz_load_balancer CPU (if there is one) otherwise fallback to any idle
+ * CPU (if there is one).
+ */
+static void nohz_balancer_kick(int cpu)
+{
+ int ilb_cpu;
+
+ nohz.next_balance++;
+
+ ilb_cpu = find_new_ilb(cpu);
+
+ if (ilb_cpu >= nr_cpu_ids)
+ return;
+
+ if (test_and_set_bit(NOHZ_BALANCE_KICK, nohz_flags(ilb_cpu)))
+ 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);
+ return;
+}
+
+static inline void clear_nohz_tick_stopped(int cpu)
+{
+ if (unlikely(test_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu)))) {
+ cpumask_clear_cpu(cpu, nohz.idle_cpus_mask);
+ atomic_dec(&nohz.nr_cpus);
+ clear_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu));
+ }
+}
+
+static inline void set_cpu_sd_state_busy(void)
+{
+ struct sched_domain *sd;
+ int cpu = smp_processor_id();
+
+ if (!test_bit(NOHZ_IDLE, nohz_flags(cpu)))
+ return;
+ clear_bit(NOHZ_IDLE, nohz_flags(cpu));
+
+ rcu_read_lock();
+ for_each_domain(cpu, sd)
+ atomic_inc(&sd->groups->sgp->nr_busy_cpus);
+ rcu_read_unlock();
+}
+
+void set_cpu_sd_state_idle(void)
+{
+ struct sched_domain *sd;
+ int cpu = smp_processor_id();
+
+ if (test_bit(NOHZ_IDLE, nohz_flags(cpu)))
+ return;
+ set_bit(NOHZ_IDLE, nohz_flags(cpu));
+
+ rcu_read_lock();
+ for_each_domain(cpu, sd)
+ atomic_dec(&sd->groups->sgp->nr_busy_cpus);
+ rcu_read_unlock();
+}
+
+/*
+ * This routine will record that this cpu is going idle with tick stopped.
+ * This info will be used in performing idle load balancing in the future.
+ */
+void select_nohz_load_balancer(int stop_tick)
+{
+ int cpu = smp_processor_id();
+
+ /*
+ * If this cpu is going down, then nothing needs to be done.
+ */
+ if (!cpu_active(cpu))
+ return;
+
+ if (stop_tick) {
+ if (test_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu)))
+ return;
+
+ cpumask_set_cpu(cpu, nohz.idle_cpus_mask);
+ atomic_inc(&nohz.nr_cpus);
+ set_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu));
+ }
+ return;
+}
+
+static int __cpuinit sched_ilb_notifier(struct notifier_block *nfb,
+ unsigned long action, void *hcpu)
+{
+ switch (action & ~CPU_TASKS_FROZEN) {
+ case CPU_DYING:
+ clear_nohz_tick_stopped(smp_processor_id());
+ return NOTIFY_OK;
+ default:
+ return NOTIFY_DONE;
+ }
+}
+#endif
+
+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 arch_init_sched_domains.
+ */
+static void rebalance_domains(int cpu, enum cpu_idle_type idle)
+{
+ int balance = 1;
+ struct rq *rq = 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;
+
+ update_shares(cpu);
+
+ rcu_read_lock();
+ for_each_domain(cpu, sd) {
+ if (!(sd->flags & SD_LOAD_BALANCE))
+ continue;
+
+ interval = sd->balance_interval;
+ if (idle != CPU_IDLE)
+ interval *= sd->busy_factor;
+
+ /* scale ms to jiffies */
+ interval = msecs_to_jiffies(interval);
+ interval = clamp(interval, 1UL, max_load_balance_interval);
+
+ 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, &balance)) {
+ /*
+ * We've pulled tasks over so either we're no
+ * longer idle.
+ */
+ idle = CPU_NOT_IDLE;
+ }
+ sd->last_balance = jiffies;
+ }
+ 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;
+ }
+
+ /*
+ * Stop the load balance at this level. There is another
+ * CPU in our sched group which is doing load balancing more
+ * actively.
+ */
+ if (!balance)
+ break;
+ }
+ 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
+/*
+ * In CONFIG_NO_HZ case, the idle balance kickee will do the
+ * rebalancing for all the cpus for whom scheduler ticks are stopped.
+ */
+static void nohz_idle_balance(int this_cpu, enum cpu_idle_type idle)
+{
+ struct rq *this_rq = cpu_rq(this_cpu);
+ struct rq *rq;
+ int balance_cpu;
+
+ if (idle != CPU_IDLE ||
+ !test_bit(NOHZ_BALANCE_KICK, nohz_flags(this_cpu)))
+ goto end;
+
+ 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())
+ break;
+
+ raw_spin_lock_irq(&this_rq->lock);
+ update_rq_clock(this_rq);
+ update_idle_cpu_load(this_rq);
+ raw_spin_unlock_irq(&this_rq->lock);
+
+ rebalance_domains(balance_cpu, CPU_IDLE);
+
+ rq = cpu_rq(balance_cpu);
+ if (time_after(this_rq->next_balance, rq->next_balance))
+ this_rq->next_balance = rq->next_balance;
+ }
+ nohz.next_balance = this_rq->next_balance;
+end:
+ clear_bit(NOHZ_BALANCE_KICK, nohz_flags(this_cpu));
+}
+
+/*
+ * Current heuristic for kicking the idle load balancer in the presence
+ * of an idle cpu is the system.
+ * - This rq has more than one task.
+ * - At any scheduler domain level, this cpu's scheduler group has multiple
+ * busy cpu's exceeding the group's power.
+ * - For SD_ASYM_PACKING, if the lower numbered cpu's in the scheduler
+ * domain span are idle.
+ */
+static inline int nohz_kick_needed(struct rq *rq, int cpu)
+{
+ unsigned long now = jiffies;
+ struct sched_domain *sd;
+
+ if (unlikely(idle_cpu(cpu)))
+ return 0;
+
+ /*
+ * 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.
+ */
+ set_cpu_sd_state_busy();
+ clear_nohz_tick_stopped(cpu);
+
+ /*
+ * None are in tickless mode and hence no need for NOHZ idle load
+ * balancing.
+ */
+ if (likely(!atomic_read(&nohz.nr_cpus)))
+ return 0;
+
+ if (time_before(now, nohz.next_balance))
+ return 0;
+
+ if (rq->nr_running >= 2)
+ goto need_kick;
+
+ rcu_read_lock();
+ for_each_domain(cpu, sd) {
+ struct sched_group *sg = sd->groups;
+ struct sched_group_power *sgp = sg->sgp;
+ int nr_busy = atomic_read(&sgp->nr_busy_cpus);
+
+ if (sd->flags & SD_SHARE_PKG_RESOURCES && nr_busy > 1)
+ goto need_kick_unlock;
+
+ if (sd->flags & SD_ASYM_PACKING && nr_busy != sg->group_weight
+ && (cpumask_first_and(nohz.idle_cpus_mask,
+ sched_domain_span(sd)) < cpu))
+ goto need_kick_unlock;
+
+ if (!(sd->flags & (SD_SHARE_PKG_RESOURCES | SD_ASYM_PACKING)))
+ break;
+ }
+ rcu_read_unlock();
+ return 0;
+
+need_kick_unlock:
+ rcu_read_unlock();
+need_kick:
+ return 1;
+}
+#else
+static void nohz_idle_balance(int this_cpu, enum cpu_idle_type idle) { }
+#endif
+
+/*
+ * run_rebalance_domains is triggered when needed from the scheduler tick.
+ * Also triggered for nohz idle balancing (with nohz_balancing_kick set).
+ */
+static void run_rebalance_domains(struct softirq_action *h)
+{
+ int this_cpu = smp_processor_id();
+ struct rq *this_rq = cpu_rq(this_cpu);
+ enum cpu_idle_type idle = this_rq->idle_balance ?
+ CPU_IDLE : CPU_NOT_IDLE;
+
+ rebalance_domains(this_cpu, 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.
+ */
+ nohz_idle_balance(this_cpu, idle);
+}
+
+static inline int on_null_domain(int cpu)
+{
+ return !rcu_dereference_sched(cpu_rq(cpu)->sd);
+}
+
+/*
+ * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing.
+ */
+void trigger_load_balance(struct rq *rq, int cpu)
+{
+ /* Don't need to rebalance while attached to NULL domain */
+ if (time_after_eq(jiffies, rq->next_balance) &&
+ likely(!on_null_domain(cpu)))
+ raise_softirq(SCHED_SOFTIRQ);
+#ifdef CONFIG_NO_HZ
+ if (nohz_kick_needed(rq, cpu) && likely(!on_null_domain(cpu)))
+ nohz_balancer_kick(cpu);
+#endif
+}
+
+static void rq_online_fair(struct rq *rq)
+{
+ update_sysctl();
+}
+
+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:
+ */
+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);
+ }
+}
+
+/*
+ * 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;
+ int this_cpu = smp_processor_id();
+ struct rq *rq = this_rq();
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&rq->lock, flags);
+
+ update_rq_clock(rq);
+
+ cfs_rq = task_cfs_rq(current);
+ curr = cfs_rq->curr;
+
+ /*
+ * Not only the cpu but also the task_group of the parent might have
+ * been changed after parent->se.parent,cfs_rq were copied to
+ * child->se.parent,cfs_rq. So call __set_task_cpu() to make those
+ * of child point to valid ones.
+ */
+ rcu_read_lock();
+ __set_task_cpu(p, this_cpu);
+ rcu_read_unlock();
+
+ update_curr(cfs_rq);
+
+ if (curr)
+ 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_task(rq->curr);
+ }
+
+ se->vruntime -= cfs_rq->min_vruntime;
+
+ raw_spin_unlock_irqrestore(&rq->lock, flags);
+}
+
+/*
+ * 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 (!p->se.on_rq)
+ 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_task(rq->curr);
+ } else
+ check_preempt_curr(rq, p, 0);
+}
+
+static void switched_from_fair(struct rq *rq, struct task_struct *p)
+{
+ struct sched_entity *se = &p->se;
+ struct cfs_rq *cfs_rq = cfs_rq_of(se);
+
+ /*
+ * Ensure the task's vruntime is normalized, so that when it's
+ * switched back to the fair class the enqueue_entity(.flags=0) will
+ * do the right thing.
+ *
+ * If it's on_rq, then the dequeue_entity(.flags=0) will already
+ * have normalized the vruntime, if it's !on_rq, then only when
+ * the task is sleeping will it still have non-normalized vruntime.
+ */
+ if (!p->on_rq && p->state != TASK_RUNNING) {
+ /*
+ * 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;
+ }
+}
+
+/*
+ * We switched to the sched_fair class.
+ */
+static void switched_to_fair(struct rq *rq, struct task_struct *p)
+{
+ if (!p->se.on_rq)
+ return;
+
+ /*
+ * 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_task(rq->curr);
+ 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_curr_task_fair(struct rq *rq)
+{
+ struct sched_entity *se = &rq->curr->se;
+
+ 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;
+ cfs_rq->min_vruntime = (u64)(-(1LL << 20));
+#ifndef CONFIG_64BIT
+ cfs_rq->min_vruntime_copy = cfs_rq->min_vruntime;
+#endif
+}
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+static void task_move_group_fair(struct task_struct *p, int on_rq)
+{
+ /*
+ * If the task was not on the rq at the time of this cgroup movement
+ * it must have been asleep, sleeping tasks keep their ->vruntime
+ * absolute on their old rq until wakeup (needed for the fair sleeper
+ * bonus in place_entity()).
+ *
+ * If it was on the rq, we've just 'preempted' it, which does convert
+ * ->vruntime to a relative base.
+ *
+ * Make sure both cases convert their relative position when migrating
+ * to another cgroup's rq. This does somewhat interfere with the
+ * fair sleeper stuff for the first placement, but who cares.
+ */
+ /*
+ * When !on_rq, vruntime of the task has usually NOT been normalized.
+ * But there are some cases where it has already been normalized:
+ *
+ * - Moving a forked child which is waiting for being woken up by
+ * wake_up_new_task().
+ * - Moving a task which has been woken up by try_to_wake_up() and
+ * waiting for actually being woken up by sched_ttwu_pending().
+ *
+ * To prevent boost or penalty in the new cfs_rq caused by delta
+ * min_vruntime between the two cfs_rqs, we skip vruntime adjustment.
+ */
+ if (!on_rq && (!p->se.sum_exec_runtime || p->state == TASK_WAKING))
+ on_rq = 1;
+
+ if (!on_rq)
+ p->se.vruntime -= cfs_rq_of(&p->se)->min_vruntime;
+ set_task_rq(p, task_cpu(p));
+ if (!on_rq)
+ p->se.vruntime += cfs_rq_of(&p->se)->min_vruntime;
+}
+
+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 cfs_rq *cfs_rq;
+ struct sched_entity *se;
+ int i;
+
+ tg->cfs_rq = kzalloc(sizeof(cfs_rq) * nr_cpu_ids, GFP_KERNEL);
+ if (!tg->cfs_rq)
+ goto err;
+ tg->se = kzalloc(sizeof(se) * nr_cpu_ids, 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]);
+ }
+
+ return 1;
+
+err_free_rq:
+ kfree(cfs_rq);
+err:
+ return 0;
+}
+
+void unregister_fair_sched_group(struct task_group *tg, int cpu)
+{
+ struct rq *rq = cpu_rq(cpu);
+ unsigned long flags;
+
+ /*
+ * 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)
+ return;
+
+ 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;
+#ifdef CONFIG_SMP
+ /* allow initial update_cfs_load() to truncate */
+ cfs_rq->load_stamp = 1;
+#endif
+ 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;
+ else
+ se->cfs_rq = parent->my_q;
+
+ 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;
+ unsigned long flags;
+
+ /*
+ * 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;
+
+ se = tg->se[i];
+ /* Propagate contribution to hierarchy */
+ raw_spin_lock_irqsave(&rq->lock, flags);
+ for_each_sched_entity(se)
+ update_cfs_shares(group_cfs_rq(se));
+ raw_spin_unlock_irqrestore(&rq->lock, flags);
+ }
+
+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 unregister_fair_sched_group(struct task_group *tg, int cpu) { }
+
+#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,
+
+#ifdef CONFIG_SMP
+ .select_task_rq = select_task_rq_fair,
+
+ .rq_online = rq_online_fair,
+ .rq_offline = rq_offline_fair,
+
+ .task_waking = task_waking_fair,
+#endif
+
+ .set_curr_task = set_curr_task_fair,
+ .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,
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+ .task_move_group = task_move_group_fair,
+#endif
+};
+
+#ifdef CONFIG_SCHED_DEBUG
+void print_cfs_stats(struct seq_file *m, int cpu)
+{
+ struct cfs_rq *cfs_rq;
+
+ rcu_read_lock();
+ for_each_leaf_cfs_rq(cpu_rq(cpu), cfs_rq)
+ print_cfs_rq(m, cpu, cfs_rq);
+ rcu_read_unlock();
+}
+#endif
+
+__init void init_sched_fair_class(void)
+{
+#ifdef CONFIG_SMP
+ open_softirq(SCHED_SOFTIRQ, run_rebalance_domains);
+
+#ifdef CONFIG_NO_HZ
+ nohz.next_balance = jiffies;
+ zalloc_cpumask_var(&nohz.idle_cpus_mask, GFP_NOWAIT);
+ cpu_notifier(sched_ilb_notifier, 0);
+#endif
+#endif /* SMP */
+
+}