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 void __resctrl_sched_in(void) |
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 | |
60 | /* |
61 | * If this task has a closid/rmid assigned, use it. |
62 | * Else use the closid/rmid assigned to this cpu. |
63 | */ |
64 | if (static_branch_likely(&rdt_alloc_enable_key)) { |
65 | if (current->closid) |
66 | closid = current->closid; |
67 | } |
68 | |
69 | if (static_branch_likely(&rdt_mon_enable_key)) { |
70 | if (current->rmid) |
71 | rmid = current->rmid; |
72 | } |
73 | |
74 | if (closid != state->cur_closid || rmid != state->cur_rmid) { |
75 | state->cur_closid = closid; |
76 | state->cur_rmid = rmid; |
77 | wrmsr(IA32_PQR_ASSOC, rmid, closid); |
78 | } |
79 | } |
80 | |
81 | static inline void resctrl_sched_in(void) |
82 | { |
83 | if (static_branch_likely(&rdt_enable_key)) |
84 | __resctrl_sched_in(); |
85 | } |
86 | |
87 | #else |
88 | |
89 | static inline void resctrl_sched_in(void) {} |
90 | |
91 | #endif /* CONFIG_X86_CPU_RESCTRL */ |
92 | |
93 | #endif /* _ASM_X86_RESCTRL_SCHED_H */ |
94 | |