From: Vinay Belgaumkar <vinay.belgaum...@intel.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.demar...@intel.com> Cc: Rodrigo Vivi <rodrigo.v...@intel.com> Cc: Lucas De Marchi <lucas.demar...@intel.com> Signed-off-by: Vinay Belgaumkar <vinay.belgaum...@intel.com> Reviewed-by: Lucas De Marchi <lucas.demar...@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20250110173308.2412232-2-lucas.demar...@intel.com Signed-off-by: Lucas De Marchi <lucas.demar...@intel.com> Signed-off-by: Sasha Levin <sas...@kernel.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
