Commit d160dc6f authored by Vinay Belgaumkar's avatar Vinay Belgaumkar Committed by Lucas De Marchi
Browse files

drm/xe: Add locks in gtidle code 



The update of the residency values needs to be protected by a lock to
avoid multiple entrypoints, for example when multiple userspace clients
read the sysfs file. Other in-kernel clients are going to be added to
sample these values, making the problem worse. Protect those updates
with a raw_spinlock so it can be called by future integration with perf
pmu.

Suggested-by: default avatarLucas De Marchi <lucas.demarchi@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: default avatarVinay Belgaumkar <vinay.belgaumkar@intel.com>
Reviewed-by: default avatarLucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250110173308.2412232-2-lucas.demarchi@intel.com


Signed-off-by: default avatarLucas De Marchi <lucas.demarchi@intel.com>
parent c26f22da

drivers/gpu/drm/xe/xe_gt_idle.c

+20 −3
Original line number Diff line number Diff line
@@ -69,6 +69,8 @@ static u64 get_residency_ms(struct xe_gt_idle *gtidle, u64 cur_residency) 
{

	u64 delta, overflow_residency, prev_residency;



	lockdep_assert_held(&gtidle->lock);



	overflow_residency = BIT_ULL(32);



	/*
@@ -275,8 +277,21 @@ static ssize_t idle_status_show(struct device *dev, 


	return sysfs_emit(buff, "%s\n", gt_idle_state_to_string(state));

}

static DEVICE_ATTR_RO(idle_status);



u64 xe_gt_idle_residency_msec(struct xe_gt_idle *gtidle)

{

	struct xe_guc_pc *pc = gtidle_to_pc(gtidle);

	u64 residency;

	unsigned long flags;



	raw_spin_lock_irqsave(&gtidle->lock, flags);

	residency = get_residency_ms(gtidle, gtidle->idle_residency(pc));

	raw_spin_unlock_irqrestore(&gtidle->lock, flags);



	return residency;

}



static DEVICE_ATTR_RO(idle_status);

static ssize_t idle_residency_ms_show(struct device *dev,

				      struct device_attribute *attr, char *buff)

{
@@ -285,10 +300,10 @@ static ssize_t idle_residency_ms_show(struct device *dev, 
	u64 residency;



	xe_pm_runtime_get(pc_to_xe(pc));

	residency = gtidle->idle_residency(pc);

	residency = xe_gt_idle_residency_msec(gtidle);

	xe_pm_runtime_put(pc_to_xe(pc));



	return sysfs_emit(buff, "%llu\n", get_residency_ms(gtidle, residency));

	return sysfs_emit(buff, "%llu\n", residency);

}

static DEVICE_ATTR_RO(idle_residency_ms);
@@ -331,6 +346,8 @@ int xe_gt_idle_init(struct xe_gt_idle *gtidle) 
	if (!kobj)

		return -ENOMEM;



	raw_spin_lock_init(&gtidle->lock);



	if (xe_gt_is_media_type(gt)) {

		snprintf(gtidle->name, sizeof(gtidle->name), "gt%d-mc", gt->info.id);

		gtidle->idle_residency = xe_guc_pc_mc6_residency;

drivers/gpu/drm/xe/xe_gt_idle.h

+1 −0
Original line number Diff line number Diff line
@@ -17,5 +17,6 @@ void xe_gt_idle_disable_c6(struct xe_gt *gt); 
void xe_gt_idle_enable_pg(struct xe_gt *gt);

void xe_gt_idle_disable_pg(struct xe_gt *gt);

int xe_gt_idle_pg_print(struct xe_gt *gt, struct drm_printer *p);

u64 xe_gt_idle_residency_msec(struct xe_gt_idle *gtidle);



#endif /* _XE_GT_IDLE_H_ */

drivers/gpu/drm/xe/xe_gt_idle_types.h

+3 −0
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ 
#ifndef _XE_GT_IDLE_SYSFS_TYPES_H_

#define _XE_GT_IDLE_SYSFS_TYPES_H_



#include <linux/spinlock.h>

#include <linux/types.h>



struct xe_guc_pc;
@@ -31,6 +32,8 @@ struct xe_gt_idle { 
	u64 cur_residency;

	/** @prev_residency: previous residency counter */

	u64 prev_residency;

	/** @lock: Lock protecting idle residency counters */

	raw_spinlock_t lock;

	/** @idle_status: get the current idle state */

	enum xe_gt_idle_state (*idle_status)(struct xe_guc_pc *pc);

	/** @idle_residency: get idle residency counter */