1 | /* SPDX-License-Identifier: GPL-2.0 */ |
---|---|
2 | #ifndef _ASM_X86_RESCTRL_H |
3 | #define _ASM_X86_RESCTRL_H |
4 | |
5 | #ifdef CONFIG_X86_CPU_RESCTRL |
6 | |
7 | #include <linux/sched.h> |
8 | #include <linux/jump_label.h> |
9 | |
10 | /** |
11 | * struct resctrl_pqr_state - State cache for the PQR MSR |
12 | * @cur_rmid: The cached Resource Monitoring ID |
13 | * @cur_closid: The cached Class Of Service ID |
14 | * @default_rmid: The user assigned Resource Monitoring ID |
15 | * @default_closid: The user assigned cached Class Of Service ID |
16 | * |
17 | * The upper 32 bits of MSR_IA32_PQR_ASSOC contain closid and the |
18 | * lower 10 bits rmid. The update to MSR_IA32_PQR_ASSOC always |
19 | * contains both parts, so we need to cache them. This also |
20 | * stores the user configured per cpu CLOSID and RMID. |
21 | * |
22 | * The cache also helps to avoid pointless updates if the value does |
23 | * not change. |
24 | */ |
25 | struct resctrl_pqr_state { |
26 | u32 cur_rmid; |
27 | u32 cur_closid; |
28 | u32 default_rmid; |
29 | u32 default_closid; |
30 | }; |
31 | |
32 | DECLARE_PER_CPU(struct resctrl_pqr_state, pqr_state); |
33 | |
34 | DECLARE_STATIC_KEY_FALSE(rdt_enable_key); |
35 | DECLARE_STATIC_KEY_FALSE(rdt_alloc_enable_key); |
36 | DECLARE_STATIC_KEY_FALSE(rdt_mon_enable_key); |
37 | |
38 | /* |
39 | * __resctrl_sched_in() - Writes the task's CLOSid/RMID to IA32_PQR_MSR |
40 | * |
41 | * Following considerations are made so that this has minimal impact |
42 | * on scheduler hot path: |
43 | * - This will stay as no-op unless we are running on an Intel SKU |
44 | * which supports resource control or monitoring and we enable by |
45 | * mounting the resctrl file system. |
46 | * - Caches the per cpu CLOSid/RMID values and does the MSR write only |
47 | * when a task with a different CLOSid/RMID is scheduled in. |
48 | * - We allocate RMIDs/CLOSids globally in order to keep this as |
49 | * simple as possible. |
50 | * Must be called with preemption disabled. |
51 | */ |
52 | static inline void __resctrl_sched_in(struct task_struct *tsk) |
53 | { |
54 | struct resctrl_pqr_state *state = this_cpu_ptr(&pqr_state); |
55 | u32 closid = state->default_closid; |
56 | u32 rmid = state->default_rmid; |
57 | u32 tmp; |
58 | |
59 | /* |
60 | * If this task has a closid/rmid assigned, use it. |
61 | * Else use the closid/rmid assigned to this cpu. |
62 | */ |
63 | if (static_branch_likely(&rdt_alloc_enable_key)) { |
64 | tmp = READ_ONCE(tsk->closid); |
65 | if (tmp) |
66 | closid = tmp; |
67 | } |
68 | |
69 | if (static_branch_likely(&rdt_mon_enable_key)) { |
70 | tmp = READ_ONCE(tsk->rmid); |
71 | if (tmp) |
72 | rmid = tmp; |
73 | } |
74 | |
75 | if (closid != state->cur_closid || rmid != state->cur_rmid) { |
76 | state->cur_closid = closid; |
77 | state->cur_rmid = rmid; |
78 | wrmsr(MSR_IA32_PQR_ASSOC, rmid, closid); |
79 | } |
80 | } |
81 | |
82 | static inline unsigned int resctrl_arch_round_mon_val(unsigned int val) |
83 | { |
84 | unsigned int scale = boot_cpu_data.x86_cache_occ_scale; |
85 | |
86 | /* h/w works in units of "boot_cpu_data.x86_cache_occ_scale" */ |
87 | val /= scale; |
88 | return val * scale; |
89 | } |
90 | |
91 | static inline void resctrl_sched_in(struct task_struct *tsk) |
92 | { |
93 | if (static_branch_likely(&rdt_enable_key)) |
94 | __resctrl_sched_in(tsk); |
95 | } |
96 | |
97 | void resctrl_cpu_detect(struct cpuinfo_x86 *c); |
98 | |
99 | #else |
100 | |
101 | static inline void resctrl_sched_in(struct task_struct *tsk) {} |
102 | static inline void resctrl_cpu_detect(struct cpuinfo_x86 *c) {} |
103 | |
104 | #endif /* CONFIG_X86_CPU_RESCTRL */ |
105 | |
106 | #endif /* _ASM_X86_RESCTRL_H */ |
107 |