From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DFB1230C355 for ; Mon, 3 Nov 2025 12:44:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762173894; cv=none; b=baX1MNnc5OpMgeSCD3wLmC343RloJQlp+2uaXWVTxOm2qZ7g0pm+wHL2sAKlqsKXyTlww03s7j010HZvO0EjjnPdCMnLL9rit4qUVJaIk0Q+2Qs8dfwJdBf4Ju+w4Uw+Ldha/JAlRo9kDrEZPOVixR1/iNjC/UVx3bHcQ5lIJV4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762173894; c=relaxed/simple; bh=fC0q0Mt/impFaf5uQCZJ6IZR2AGMuZ1IVzVjwS8Je1g=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=trNc/WW5Nw/++H/v8qxblKw0GCQjSUlJjO7yO9un51E5K53tbM5OzmOHCctWsnmAJAZEt+lo4XZmjqY+w4ziuespRd8vcfPKTXscBYd00gZF9wZYJU16cJq/wpp14MVwA1BqYC3LncsQOi69jLr7KDruY8/ROPBJ61pWVTWFfgw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=LT3jkvt0; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="LT3jkvt0" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8136EC4CEE7; Mon, 3 Nov 2025 12:44:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1762173893; bh=fC0q0Mt/impFaf5uQCZJ6IZR2AGMuZ1IVzVjwS8Je1g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LT3jkvt0BNkrAzHVEWWRcz9WG7l67RIm1PnLtbxjMxTVtxtbSuMxayP4FodrT4KDp Vthm+QwvBoiRo6xeQBf6LXwYJkMdNzm+3Y+8bNybpD4g4JxQwaw1Ns/EdpP1f3a5WY 47TCHgWCdYa84eg2l8UvX9tPUrDZ1DCsvaqyl5PMkV2NhrjLusOqWFJ6txtqMwqxxX zn7mQ+SzvGH+KyZ+WPkXrBq1EhL/z2BlxHQw2+GoCMXWWEXlOcj8vCPPWk+OLYQKNm OwEdyejVPSES2zxrWHICwW9CXljoqFcdJBZs16n713bmf0iC9JgOiRFdVwQ43FcTP/ LOQwravldeaLQ== From: Sasha Levin To: stable@vger.kernel.org Cc: Tvrtko Ursulin , =?UTF-8?q?Christian=20K=C3=B6nig?= , Alex Deucher , Luben Tuikov , Matthew Brost , Philipp Stanner , Sasha Levin Subject: [PATCH 6.12.y 1/3] drm/sched: Optimise drm_sched_entity_push_job Date: Mon, 3 Nov 2025 07:44:48 -0500 Message-ID: <20251103124450.4002293-1-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <2025110342-exhume-mankind-5952@gregkh> References: <2025110342-exhume-mankind-5952@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Tvrtko Ursulin [ Upstream commit d42a254633c773921884a19e8a1a0f53a31150c3 ] In FIFO mode (which is the default), both drm_sched_entity_push_job() and drm_sched_rq_update_fifo(), where the latter calls the former, are currently taking and releasing the same entity->rq_lock. We can avoid that design inelegance, and also have a miniscule efficiency improvement on the submit from idle path, by introducing a new drm_sched_rq_update_fifo_locked() helper and pulling up the lock taking to its callers. v2: * Remove drm_sched_rq_update_fifo() altogether. (Christian) v3: * Improved commit message. (Philipp) Signed-off-by: Tvrtko Ursulin Cc: Christian König Cc: Alex Deucher Cc: Luben Tuikov Cc: Matthew Brost Cc: Philipp Stanner Reviewed-by: Christian König Signed-off-by: Philipp Stanner Link: https://patchwork.freedesktop.org/patch/msgid/20241016122013.7857-2-tursulin@igalia.com Stable-dep-of: d25e3a610bae ("drm/sched: Fix race in drm_sched_entity_select_rq()") Signed-off-by: Sasha Levin --- drivers/gpu/drm/scheduler/sched_entity.c | 13 +++++++++---- drivers/gpu/drm/scheduler/sched_main.c | 6 +++--- include/drm/gpu_scheduler.h | 2 +- 3 files changed, 13 insertions(+), 8 deletions(-) diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c index 3e75fc1f66072..9dbae7b08bc90 100644 --- a/drivers/gpu/drm/scheduler/sched_entity.c +++ b/drivers/gpu/drm/scheduler/sched_entity.c @@ -505,8 +505,12 @@ struct drm_sched_job *drm_sched_entity_pop_job(struct drm_sched_entity *entity) struct drm_sched_job *next; next = to_drm_sched_job(spsc_queue_peek(&entity->job_queue)); - if (next) - drm_sched_rq_update_fifo(entity, next->submit_ts); + if (next) { + spin_lock(&entity->rq_lock); + drm_sched_rq_update_fifo_locked(entity, + next->submit_ts); + spin_unlock(&entity->rq_lock); + } } /* Jobs and entities might have different lifecycles. Since we're @@ -606,10 +610,11 @@ void drm_sched_entity_push_job(struct drm_sched_job *sched_job) sched = rq->sched; drm_sched_rq_add_entity(rq, entity); - spin_unlock(&entity->rq_lock); if (drm_sched_policy == DRM_SCHED_POLICY_FIFO) - drm_sched_rq_update_fifo(entity, submit_ts); + drm_sched_rq_update_fifo_locked(entity, submit_ts); + + spin_unlock(&entity->rq_lock); drm_sched_wakeup(sched); } diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c index d5260cb1ed0ec..0b7976c908dde 100644 --- a/drivers/gpu/drm/scheduler/sched_main.c +++ b/drivers/gpu/drm/scheduler/sched_main.c @@ -169,14 +169,15 @@ static inline void drm_sched_rq_remove_fifo_locked(struct drm_sched_entity *enti } } -void drm_sched_rq_update_fifo(struct drm_sched_entity *entity, ktime_t ts) +void drm_sched_rq_update_fifo_locked(struct drm_sched_entity *entity, ktime_t ts) { /* * Both locks need to be grabbed, one to protect from entity->rq change * for entity from within concurrent drm_sched_entity_select_rq and the * other to update the rb tree structure. */ - spin_lock(&entity->rq_lock); + lockdep_assert_held(&entity->rq_lock); + spin_lock(&entity->rq->lock); drm_sched_rq_remove_fifo_locked(entity); @@ -187,7 +188,6 @@ void drm_sched_rq_update_fifo(struct drm_sched_entity *entity, ktime_t ts) drm_sched_entity_compare_before); spin_unlock(&entity->rq->lock); - spin_unlock(&entity->rq_lock); } /** diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h index 9c437a057e5de..346a3c261b437 100644 --- a/include/drm/gpu_scheduler.h +++ b/include/drm/gpu_scheduler.h @@ -593,7 +593,7 @@ void drm_sched_rq_add_entity(struct drm_sched_rq *rq, void drm_sched_rq_remove_entity(struct drm_sched_rq *rq, struct drm_sched_entity *entity); -void drm_sched_rq_update_fifo(struct drm_sched_entity *entity, ktime_t ts); +void drm_sched_rq_update_fifo_locked(struct drm_sched_entity *entity, ktime_t ts); int drm_sched_entity_init(struct drm_sched_entity *entity, enum drm_sched_priority priority, -- 2.51.0