[mirror_ubuntu-disco-kernel.git] / arch / x86 / include / asm / intel_rdt_sched.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_X86_INTEL_RDT_SCHED_H
#define _ASM_X86_INTEL_RDT_SCHED_H

#ifdef CONFIG_INTEL_RDT

#include <linux/sched.h>
#include <linux/jump_label.h>

#define IA32_PQR_ASSOC	0x0c8f

/**
 * struct intel_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 intel_pqr_state {
	u32			cur_rmid;
	u32			cur_closid;
	u32			default_rmid;
	u32			default_closid;
};

DECLARE_PER_CPU(struct intel_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);

/*
 * __intel_rdt_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 __intel_rdt_sched_in(void)
{
	struct intel_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 intel_rdt_sched_in(void)
{
	if (static_branch_likely(&rdt_enable_key))
		__intel_rdt_sched_in();
}

#else

static inline void intel_rdt_sched_in(void) {}

#endif /* CONFIG_INTEL_RDT */

#endif /* _ASM_X86_INTEL_RDT_SCHED_H */
Commit	Line	Data
b2441318	1	/* SPDX-License-Identifier: GPL-2.0 */
05830204 VS	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
a9110b55 VS	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
05830204 VS	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
748b6b88 VS	21	* contains both parts, so we need to cache them. This also
748b6b88 VS	22	* stores the user configured per cpu CLOSID and RMID.
05830204 VS	23	*
	24	* The cache also helps to avoid pointless updates if the value does
	25	* not change.
	26	*/
	27	struct intel_pqr_state {
a9110b55 VS	28	u32 cur_rmid;
	29	u32 cur_closid;
	30	u32 default_rmid;
	31	u32 default_closid;
05830204 VS	32	};
	33
	34	DECLARE_PER_CPU(struct intel_pqr_state, pqr_state);
4be6c078 VS	35
4be6c078 VS	36	DECLARE_STATIC_KEY_FALSE(rdt_enable_key);
1b5c0b75	37	DECLARE_STATIC_KEY_FALSE(rdt_alloc_enable_key);
748b6b88	38	DECLARE_STATIC_KEY_FALSE(rdt_mon_enable_key);
05830204 VS	39
05830204 VS	40	/*
748b6b88	41	* __intel_rdt_sched_in() - Writes the task's CLOSid/RMID to IA32_PQR_MSR
05830204 VS	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
748b6b88 VS	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.
05830204 VS	52	* Must be called with preemption disabled.
05830204 VS	53	*/
748b6b88	54	static void __intel_rdt_sched_in(void)
05830204	55	{
a9110b55 VS	56	struct intel_pqr_state *state = this_cpu_ptr(&pqr_state);
	57	u32 closid = state->default_closid;
	58	u32 rmid = state->default_rmid;
748b6b88 VS	59
	60	/*
	61	* If this task has a closid/rmid assigned, use it.
	62	* Else use the closid/rmid assigned to this cpu.
	63	*/
1b5c0b75	64	if (static_branch_likely(&rdt_alloc_enable_key)) {
748b6b88	65	if (current->closid)
a9110b55	66	closid = current->closid;
748b6b88	67	}
05830204	68
748b6b88 VS	69	if (static_branch_likely(&rdt_mon_enable_key)) {
748b6b88 VS	70	if (current->rmid)
a9110b55	71	rmid = current->rmid;
748b6b88	72	}
05830204	73
a9110b55 VS	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);
05830204 VS	78	}
	79	}
	80
4be6c078 VS	81	static inline void intel_rdt_sched_in(void)
	82	{
	83	if (static_branch_likely(&rdt_enable_key))
	84	__intel_rdt_sched_in();
	85	}
	86
05830204 VS	87	#else
	88
	89	static inline void intel_rdt_sched_in(void) {}
	90
	91	#endif /* CONFIG_INTEL_RDT */
	92
	93	#endif /* _ASM_X86_INTEL_RDT_SCHED_H */