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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_X86_RESCTRL_SCHED_H
#define _ASM_X86_RESCTRL_SCHED_H
#ifdef CONFIG_X86_CPU_RESCTRL
#include <linux/sched.h>
#include <linux/jump_label.h>
#define IA32_PQR_ASSOC 0x0c8f
/**
* struct resctrl_pqr_state - State cache for the PQR MSR
* @cur_rmid: The cached Resource Monitoring ID
* @cur_closid: The cached Class Of Service ID
* @default_rmid: The user assigned Resource Monitoring ID
* @default_closid: The user assigned cached Class Of Service ID
*
* The upper 32 bits of IA32_PQR_ASSOC contain closid and the
* lower 10 bits rmid. The update to IA32_PQR_ASSOC always
* contains both parts, so we need to cache them. This also
* stores the user configured per cpu CLOSID and RMID.
*
* The cache also helps to avoid pointless updates if the value does
* not change.
*/
struct resctrl_pqr_state {
u32 cur_rmid;
u32 cur_closid;
u32 default_rmid;
u32 default_closid;
};
DECLARE_PER_CPU(struct resctrl_pqr_state, pqr_state);
DECLARE_STATIC_KEY_FALSE(rdt_enable_key);
DECLARE_STATIC_KEY_FALSE(rdt_alloc_enable_key);
DECLARE_STATIC_KEY_FALSE(rdt_mon_enable_key);
/*
* __resctrl_sched_in() - Writes the task's CLOSid/RMID to IA32_PQR_MSR
*
* Following considerations are made so that this has minimal impact
* on scheduler hot path:
* - This will stay as no-op unless we are running on an Intel SKU
* which supports resource control or monitoring and we enable by
* mounting the resctrl file system.
* - Caches the per cpu CLOSid/RMID values and does the MSR write only
* when a task with a different CLOSid/RMID is scheduled in.
* - We allocate RMIDs/CLOSids globally in order to keep this as
* simple as possible.
* Must be called with preemption disabled.
*/
static void __resctrl_sched_in(void)
{
struct resctrl_pqr_state *state = this_cpu_ptr(&pqr_state);
u32 closid = state->default_closid;
u32 rmid = state->default_rmid;
/*
* If this task has a closid/rmid assigned, use it.
* Else use the closid/rmid assigned to this cpu.
*/
if (static_branch_likely(&rdt_alloc_enable_key)) {
if (current->closid)
closid = current->closid;
}
if (static_branch_likely(&rdt_mon_enable_key)) {
if (current->rmid)
rmid = current->rmid;
}
if (closid != state->cur_closid || rmid != state->cur_rmid) {
state->cur_closid = closid;
state->cur_rmid = rmid;
wrmsr(IA32_PQR_ASSOC, rmid, closid);
}
}
static inline void resctrl_sched_in(void)
{
if (static_branch_likely(&rdt_enable_key))
__resctrl_sched_in();
}
#else
static inline void resctrl_sched_in(void) {}
#endif /* CONFIG_X86_CPU_RESCTRL */
#endif /* _ASM_X86_RESCTRL_SCHED_H */
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