| b.liu | e958203 | 2025-04-17 19:18:16 +0800 | [diff] [blame^] | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
| 2 | #ifndef _ASM_X86_RESCTRL_SCHED_H |
| 3 | #define _ASM_X86_RESCTRL_SCHED_H |
| 4 | |
| 5 | #ifdef CONFIG_X86_CPU_RESCTRL |
| 6 | |
| 7 | #include <linux/sched.h> |
| 8 | #include <linux/jump_label.h> |
| 9 | |
| 10 | #define IA32_PQR_ASSOC 0x0c8f |
| 11 | |
| 12 | /** |
| 13 | * struct resctrl_pqr_state - State cache for the PQR MSR |
| 14 | * @cur_rmid: The cached Resource Monitoring ID |
| 15 | * @cur_closid: The cached Class Of Service ID |
| 16 | * @default_rmid: The user assigned Resource Monitoring ID |
| 17 | * @default_closid: The user assigned cached Class Of Service ID |
| 18 | * |
| 19 | * The upper 32 bits of IA32_PQR_ASSOC contain closid and the |
| 20 | * lower 10 bits rmid. The update to IA32_PQR_ASSOC always |
| 21 | * contains both parts, so we need to cache them. This also |
| 22 | * stores the user configured per cpu CLOSID and RMID. |
| 23 | * |
| 24 | * The cache also helps to avoid pointless updates if the value does |
| 25 | * not change. |
| 26 | */ |
| 27 | struct resctrl_pqr_state { |
| 28 | u32 cur_rmid; |
| 29 | u32 cur_closid; |
| 30 | u32 default_rmid; |
| 31 | u32 default_closid; |
| 32 | }; |
| 33 | |
| 34 | DECLARE_PER_CPU(struct resctrl_pqr_state, pqr_state); |
| 35 | |
| 36 | DECLARE_STATIC_KEY_FALSE(rdt_enable_key); |
| 37 | DECLARE_STATIC_KEY_FALSE(rdt_alloc_enable_key); |
| 38 | DECLARE_STATIC_KEY_FALSE(rdt_mon_enable_key); |
| 39 | |
| 40 | /* |
| 41 | * __resctrl_sched_in() - Writes the task's CLOSid/RMID to IA32_PQR_MSR |
| 42 | * |
| 43 | * Following considerations are made so that this has minimal impact |
| 44 | * on scheduler hot path: |
| 45 | * - This will stay as no-op unless we are running on an Intel SKU |
| 46 | * which supports resource control or monitoring and we enable by |
| 47 | * mounting the resctrl file system. |
| 48 | * - Caches the per cpu CLOSid/RMID values and does the MSR write only |
| 49 | * when a task with a different CLOSid/RMID is scheduled in. |
| 50 | * - We allocate RMIDs/CLOSids globally in order to keep this as |
| 51 | * simple as possible. |
| 52 | * Must be called with preemption disabled. |
| 53 | */ |
| 54 | static inline void __resctrl_sched_in(struct task_struct *tsk) |
| 55 | { |
| 56 | struct resctrl_pqr_state *state = this_cpu_ptr(&pqr_state); |
| 57 | u32 closid = state->default_closid; |
| 58 | u32 rmid = state->default_rmid; |
| 59 | u32 tmp; |
| 60 | |
| 61 | /* |
| 62 | * If this task has a closid/rmid assigned, use it. |
| 63 | * Else use the closid/rmid assigned to this cpu. |
| 64 | */ |
| 65 | if (static_branch_likely(&rdt_alloc_enable_key)) { |
| 66 | tmp = READ_ONCE(tsk->closid); |
| 67 | if (tmp) |
| 68 | closid = tmp; |
| 69 | } |
| 70 | |
| 71 | if (static_branch_likely(&rdt_mon_enable_key)) { |
| 72 | tmp = READ_ONCE(tsk->rmid); |
| 73 | if (tmp) |
| 74 | rmid = tmp; |
| 75 | } |
| 76 | |
| 77 | if (closid != state->cur_closid || rmid != state->cur_rmid) { |
| 78 | state->cur_closid = closid; |
| 79 | state->cur_rmid = rmid; |
| 80 | wrmsr(IA32_PQR_ASSOC, rmid, closid); |
| 81 | } |
| 82 | } |
| 83 | |
| 84 | static inline void resctrl_sched_in(struct task_struct *tsk) |
| 85 | { |
| 86 | if (static_branch_likely(&rdt_enable_key)) |
| 87 | __resctrl_sched_in(tsk); |
| 88 | } |
| 89 | |
| 90 | #else |
| 91 | |
| 92 | static inline void resctrl_sched_in(struct task_struct *tsk) {} |
| 93 | |
| 94 | #endif /* CONFIG_X86_CPU_RESCTRL */ |
| 95 | |
| 96 | #endif /* _ASM_X86_RESCTRL_SCHED_H */ |