1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_X86_RESCTRL_H
3 #define _ASM_X86_RESCTRL_H
5 #ifdef CONFIG_X86_CPU_RESCTRL
7 #include <linux/sched.h>
8 #include <linux/jump_label.h>
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
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.
22 * The cache also helps to avoid pointless updates if the value does
25 struct resctrl_pqr_state {
32 DECLARE_PER_CPU(struct resctrl_pqr_state, pqr_state);
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);
39 * __resctrl_sched_in() - Writes the task's CLOSid/RMID to IA32_PQR_MSR
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
50 * Must be called with preemption disabled.
52 static inline void __resctrl_sched_in(struct task_struct *tsk)
54 struct resctrl_pqr_state *state = this_cpu_ptr(&pqr_state);
55 u32 closid = state->default_closid;
56 u32 rmid = state->default_rmid;
60 * If this task has a closid/rmid assigned, use it.
61 * Else use the closid/rmid assigned to this cpu.
63 if (static_branch_likely(&rdt_alloc_enable_key)) {
64 tmp = READ_ONCE(tsk->closid);
69 if (static_branch_likely(&rdt_mon_enable_key)) {
70 tmp = READ_ONCE(tsk->rmid);
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);
82 static inline unsigned int resctrl_arch_round_mon_val(unsigned int val)
84 unsigned int scale = boot_cpu_data.x86_cache_occ_scale;
86 /* h/w works in units of "boot_cpu_data.x86_cache_occ_scale" */
91 static inline void resctrl_sched_in(struct task_struct *tsk)
93 if (static_branch_likely(&rdt_enable_key))
94 __resctrl_sched_in(tsk);
97 void resctrl_cpu_detect(struct cpuinfo_x86 *c);
101 static inline void resctrl_sched_in(struct task_struct *tsk) {}
102 static inline void resctrl_cpu_detect(struct cpuinfo_x86 *c) {}
104 #endif /* CONFIG_X86_CPU_RESCTRL */
106 #endif /* _ASM_X86_RESCTRL_H */