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Message-Id: <20250505221419.2672473-617-sashal@kernel.org>
Date: Mon, 5 May 2025 18:13:53 -0400
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org,
stable@...r.kernel.org
Cc: Vinay Belgaumkar <vinay.belgaumkar@...el.com>,
Lucas De Marchi <lucas.demarchi@...el.com>,
Rodrigo Vivi <rodrigo.vivi@...el.com>,
Sasha Levin <sashal@...nel.org>,
thomas.hellstrom@...ux.intel.com,
airlied@...il.com,
simona@...ll.ch,
intel-xe@...ts.freedesktop.org,
dri-devel@...ts.freedesktop.org
Subject: [PATCH AUTOSEL 6.14 617/642] drm/xe: Add locks in gtidle code
From: Vinay Belgaumkar <vinay.belgaumkar@...el.com>
[ Upstream commit d160dc6f53914d729be7fcb7afbd0e9e6a3725b2 ]
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: Lucas De Marchi <lucas.demarchi@...el.com>
Cc: Rodrigo Vivi <rodrigo.vivi@...el.com>
Cc: Lucas De Marchi <lucas.demarchi@...el.com>
Signed-off-by: Vinay Belgaumkar <vinay.belgaumkar@...el.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@...el.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250110173308.2412232-2-lucas.demarchi@intel.com
Signed-off-by: Lucas De Marchi <lucas.demarchi@...el.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
drivers/gpu/drm/xe/xe_gt_idle.c | 23 ++++++++++++++++++++---
drivers/gpu/drm/xe/xe_gt_idle.h | 1 +
drivers/gpu/drm/xe/xe_gt_idle_types.h | 3 +++
3 files changed, 24 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/xe/xe_gt_idle.c b/drivers/gpu/drm/xe/xe_gt_idle.c
index ffd3ba7f66561..fbbace7b0b12a 100644
--- a/drivers/gpu/drm/xe/xe_gt_idle.c
+++ b/drivers/gpu/drm/xe/xe_gt_idle.c
@@ -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(>idle->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(>idle->lock, flags);
+ residency = get_residency_ms(gtidle, gtidle->idle_residency(pc));
+ raw_spin_unlock_irqrestore(>idle->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(>idle->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;
diff --git a/drivers/gpu/drm/xe/xe_gt_idle.h b/drivers/gpu/drm/xe/xe_gt_idle.h
index 4455a6501cb07..591a01e181bcc 100644
--- a/drivers/gpu/drm/xe/xe_gt_idle.h
+++ b/drivers/gpu/drm/xe/xe_gt_idle.h
@@ -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_ */
diff --git a/drivers/gpu/drm/xe/xe_gt_idle_types.h b/drivers/gpu/drm/xe/xe_gt_idle_types.h
index b8b297a3f8848..a3667c567f8a7 100644
--- a/drivers/gpu/drm/xe/xe_gt_idle_types.h
+++ b/drivers/gpu/drm/xe/xe_gt_idle_types.h
@@ -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 */
--
2.39.5
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