1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _ASM_X86_INTEL_RDT_SCHED_H 3 #define _ASM_X86_INTEL_RDT_SCHED_H 4 5 #ifdef CONFIG_INTEL_RDT 6 7 #include <linux/sched.h> 8 #include <linux/jump_label.h> 9 10 #define IA32_PQR_ASSOC 0x0c8f 11 12 /** 13 * struct intel_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 intel_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 intel_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 * __intel_rdt_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 */ __intel_rdt_sched_in(void)54static void __intel_rdt_sched_in(void) 55 { 56 struct intel_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 intel_rdt_sched_in(void)81static inline void intel_rdt_sched_in(void) 82 { 83 if (static_branch_likely(&rdt_enable_key)) 84 __intel_rdt_sched_in(); 85 } 86 87 #else 88 intel_rdt_sched_in(void)89static inline void intel_rdt_sched_in(void) {} 90 91 #endif /* CONFIG_INTEL_RDT */ 92 93 #endif /* _ASM_X86_INTEL_RDT_SCHED_H */ 94
