linux-kernel - [PATCH 2/3] drm/i915: replace use of system_wq with system_percpu

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Message-ID: <20251031100923.85721-3-marco.crivellari@suse.com>
Date: Fri, 31 Oct 2025 11:09:22 +0100
From: Marco Crivellari <marco.crivellari@...e.com>
To: linux-kernel@...r.kernel.org,
	intel-gfx@...ts.freedesktop.org,
	dri-devel@...ts.freedesktop.org
Cc: Tejun Heo <tj@...nel.org>,
	Lai Jiangshan <jiangshanlai@...il.com>,
	Frederic Weisbecker <frederic@...nel.org>,
	Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
	Marco Crivellari <marco.crivellari@...e.com>,
	Michal Hocko <mhocko@...e.com>,
	Jani Nikula <jani.nikula@...ux.intel.com>,
	Joonas Lahtinen <joonas.lahtinen@...ux.intel.com>,
	Rodrigo Vivi <rodrigo.vivi@...el.com>,
	Tvrtko Ursulin <tursulin@...ulin.net>,
	David Airlie <airlied@...il.com>,
	Simona Vetter <simona@...ll.ch>
Subject: [PATCH 2/3] drm/i915: replace use of system_wq with system_percpu_wq

Currently if a user enqueue a work item using schedule_delayed_work() the
used wq is "system_wq" (per-cpu wq) while queue_delayed_work() use
WORK_CPU_UNBOUND (used when a cpu is not specified). The same applies to
schedule_work() that is using system_wq and queue_work(), that makes use
again of WORK_CPU_UNBOUND.

This lack of consistency cannot be addressed without refactoring the API.

system_wq should be the per-cpu workqueue, yet in this name nothing makes
that clear, so replace system_wq with system_percpu_wq.

The old wq (system_wq) will be kept for a few release cycles.

Suggested-by: Tejun Heo <tj@...nel.org>
Signed-off-by: Marco Crivellari <marco.crivellari@...e.com>
---
 drivers/gpu/drm/i915/i915_driver.c | 2 +-
 drivers/gpu/drm/i915/i915_drv.h    | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_driver.c b/drivers/gpu/drm/i915/i915_driver.c
index a28c3710c4d5..0f33cdc11736 100644
--- a/drivers/gpu/drm/i915/i915_driver.c
+++ b/drivers/gpu/drm/i915/i915_driver.c
@@ -140,7 +140,7 @@ static int i915_workqueues_init(struct drm_i915_private *dev_priv)
 	/*
 	 * The unordered i915 workqueue should be used for all work
 	 * scheduling that do not require running in order, which used
-	 * to be scheduled on the system_wq before moving to a driver
+	 * to be scheduled on the system_percpu_wq before moving to a driver
 	 * instance due deprecation of flush_scheduled_work().
 	 */
 	dev_priv->unordered_wq = alloc_workqueue("i915-unordered", 0, 0);
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 6a768aad8edd..d9f73b9995cf 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -256,7 +256,7 @@ struct drm_i915_private {
 	 *
 	 * This workqueue should be used for all unordered work
 	 * scheduling within i915, which used to be scheduled on the
-	 * system_wq before moving to a driver instance due
+	 * system_percpu_wq before moving to a driver instance due
 	 * deprecation of flush_scheduled_work().
 	 */
 	struct workqueue_struct *unordered_wq;
-- 
2.51.0