resctrl_sched

#endif /* _ASM_X86_SWITCH_TO_H */
#include <asm/vm86.h>
#include <asm/resctrl_sched.h>
/* 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) {}
函数源码
