From: Matthew Brost matthew.brost@intel.com
Drop pin count check trick between a sched_disable and re-pin, now rely on the lock and counter of the number of committed requests to determine if scheduling should be disabled on the context.
Reviewed-by: Daniele Ceraolo Spurio daniele.ceraolospurio@intel.com Signed-off-by: Matthew Brost matthew.brost@intel.com --- drivers/gpu/drm/i915/gt/intel_context_types.h | 2 + .../gpu/drm/i915/gt/uc/intel_guc_submission.c | 53 +++++++++++-------- 2 files changed, 34 insertions(+), 21 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_context_types.h b/drivers/gpu/drm/i915/gt/intel_context_types.h index d2f798ef678c..3a5d98e908f4 100644 --- a/drivers/gpu/drm/i915/gt/intel_context_types.h +++ b/drivers/gpu/drm/i915/gt/intel_context_types.h @@ -169,6 +169,8 @@ struct intel_context { struct list_head fences; /* GuC context blocked fence */ struct i915_sw_fence blocked; + /* GuC committed requests */ + int number_committed_requests; } guc_state;
struct { diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c index 987aec197658..440ddcaae627 100644 --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c @@ -249,6 +249,25 @@ static inline void decr_context_blocked(struct intel_context *ce) ce->guc_state.sched_state -= SCHED_STATE_BLOCKED; }
+static inline bool context_has_committed_requests(struct intel_context *ce) +{ + return !!ce->guc_state.number_committed_requests; +} + +static inline void incr_context_committed_requests(struct intel_context *ce) +{ + lockdep_assert_held(&ce->guc_state.lock); + ++ce->guc_state.number_committed_requests; + GEM_BUG_ON(ce->guc_state.number_committed_requests < 0); +} + +static inline void decr_context_committed_requests(struct intel_context *ce) +{ + lockdep_assert_held(&ce->guc_state.lock); + --ce->guc_state.number_committed_requests; + GEM_BUG_ON(ce->guc_state.number_committed_requests < 0); +} + static inline bool context_guc_id_invalid(struct intel_context *ce) { return ce->guc_id == GUC_INVALID_LRC_ID; @@ -1749,24 +1768,18 @@ static void guc_context_sched_disable(struct intel_context *ce) spin_lock_irqsave(&ce->guc_state.lock, flags);
/* - * We have to check if the context has been disabled by another thread. - * We also have to check if the context has been pinned again as another - * pin operation is allowed to pass this function. Checking the pin - * count, within ce->guc_state.lock, synchronizes this function with - * guc_request_alloc ensuring a request doesn't slip through the - * 'context_pending_disable' fence. Checking within the spin lock (can't - * sleep) ensures another process doesn't pin this context and generate - * a request before we set the 'context_pending_disable' flag here. + * We have to check if the context has been disabled by another thread, + * check if submssion has been disabled to seal a race with reset and + * finally check if any more requests have been committed to the + * context ensursing that a request doesn't slip through the + * 'context_pending_disable' fence. */ - if (unlikely(!context_enabled(ce) || submission_disabled(guc))) { + if (unlikely(!context_enabled(ce) || submission_disabled(guc) || + context_has_committed_requests(ce))) { clr_context_enabled(ce); spin_unlock_irqrestore(&ce->guc_state.lock, flags); goto unpin; } - if (unlikely(atomic_add_unless(&ce->pin_count, -2, 2))) { - spin_unlock_irqrestore(&ce->guc_state.lock, flags); - return; - } guc_id = prep_context_pending_disable(ce);
spin_unlock_irqrestore(&ce->guc_state.lock, flags); @@ -1796,6 +1809,7 @@ static void __guc_context_destroy(struct intel_context *ce) ce->guc_prio_count[GUC_CLIENT_PRIORITY_HIGH] || ce->guc_prio_count[GUC_CLIENT_PRIORITY_KMD_NORMAL] || ce->guc_prio_count[GUC_CLIENT_PRIORITY_NORMAL]); + GEM_BUG_ON(ce->guc_state.number_committed_requests);
lrc_fini(ce); intel_context_fini(ce); @@ -2026,6 +2040,10 @@ static void remove_from_context(struct i915_request *rq)
spin_unlock_irq(&ce->guc_active.lock);
+ spin_lock_irq(&ce->guc_state.lock); + decr_context_committed_requests(ce); + spin_unlock_irq(&ce->guc_state.lock); + atomic_dec(&ce->guc_id_ref); i915_request_notify_execute_cb_imm(rq); } @@ -2176,15 +2194,7 @@ static int guc_request_alloc(struct i915_request *rq) * schedule enable or context registration if either G2H is pending * respectfully. Once a G2H returns, the fence is released that is * blocking these requests (see guc_signal_context_fence). - * - * We can safely check the below fields outside of the lock as it isn't - * possible for these fields to transition from being clear to set but - * converse is possible, hence the need for the check within the lock. */ - if (likely(!context_wait_for_deregister_to_register(ce) && - !context_pending_disable(ce))) - return 0; - spin_lock_irqsave(&ce->guc_state.lock, flags); if (context_wait_for_deregister_to_register(ce) || context_pending_disable(ce)) { @@ -2193,6 +2203,7 @@ static int guc_request_alloc(struct i915_request *rq)
list_add_tail(&rq->guc_fence_link, &ce->guc_state.fences); } + incr_context_committed_requests(ce); spin_unlock_irqrestore(&ce->guc_state.lock, flags);
return 0;