drm/i915: add WQ_PERCPU to alloc_workqueue users

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 consistentcy cannot be addressed without refactoring the API.

alloc_workqueue() treats all queues as per-CPU by default, while unbound
workqueues must opt-in via WQ_UNBOUND.

This default is suboptimal: most workloads benefit from unbound queues,
allowing the scheduler to place worker threads where they’re needed and
reducing noise when CPUs are isolated.

This change adds a new WQ_PERCPU flag to explicitly request
alloc_workqueue() to be per-cpu when WQ_UNBOUND has not been specified.

With the introduction of the WQ_PERCPU flag (equivalent to !WQ_UNBOUND),
any alloc_workqueue() caller that doesn’t explicitly specify WQ_UNBOUND
must now use WQ_PERCPU.

This patch continues the effort to refactor worqueue APIs, which has
begun with the change introducing new workqueues:

commit 930c2ea566af ("workqueue: Add new WQ_PERCPU flag")

Once migration is complete, WQ_UNBOUND can be removed and unbound will
become the implicit default.

Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Marco Crivellari <marco.crivellari@suse.com>
Reviewed-by: Krzysztof Karas <krzysztof.karas@intel.com>
Link: https://patch.msgid.link/20251104100032.61525-4-marco.crivellari@suse.com
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

diff --git a/drivers/gpu/drm/i915/display/intel_display_driver.c b/drivers/gpu/drm/i915/display/intel_display_driver.c
index 967da2b41316b07367ebe415130d1ef44b254d3b..23bfecc983e8d4b8956e143afe06f1d0bbc20982 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_display_driver.c
+++ b/drivers/gpu/drm/i915/display/intel_display_driver.c
@@ -241,13 +241,13 @@ int intel_display_driver_probe_noirq(struct intel_display *display)
                goto cleanup_wq_modeset;
        }
 
-       display->wq.cleanup = alloc_workqueue("i915_cleanup", WQ_HIGHPRI, 0);
+       display->wq.cleanup = alloc_workqueue("i915_cleanup", WQ_HIGHPRI | WQ_PERCPU, 0);
        if (!display->wq.cleanup) {
                ret = -ENOMEM;
                goto cleanup_wq_flip;
        }
 
-       display->wq.unordered = alloc_workqueue("display_unordered", 0, 0);
+       display->wq.unordered = alloc_workqueue("display_unordered", WQ_PERCPU, 0);
        if (!display->wq.unordered) {
                ret = -ENOMEM;
                goto cleanup_wq_cleanup;

diff --git a/drivers/gpu/drm/i915/i915_driver.c b/drivers/gpu/drm/i915/i915_driver.c
index c2365853df1b2e5aeba64ab798db2c1c83fb4800..79ded07b5db530fe785174747969abd650038854 100644 (file)
--- a/drivers/gpu/drm/i915/i915_driver.c
+++ b/drivers/gpu/drm/i915/i915_driver.c
@@ -154,7 +154,8 @@ static int i915_workqueues_init(struct drm_i915_private *dev_priv)
         * 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);
+       dev_priv->unordered_wq = alloc_workqueue("i915-unordered", WQ_PERCPU,
+                                                0);
        if (dev_priv->unordered_wq == NULL)
                goto out_free_wq;
 

diff --git a/drivers/gpu/drm/i915/selftests/i915_sw_fence.c b/drivers/gpu/drm/i915/selftests/i915_sw_fence.c
index 6c376338bb37a8a5916e4b7cd6f1e64a275d9f29..6a305322e30db086ad5a7d8573a1920607ad8cc6 100644 (file)
--- a/drivers/gpu/drm/i915/selftests/i915_sw_fence.c
+++ b/drivers/gpu/drm/i915/selftests/i915_sw_fence.c
@@ -526,7 +526,7 @@ static int test_ipc(void *arg)
        struct workqueue_struct *wq;
        int ret = 0;
 
-       wq = alloc_workqueue("i1915-selftest", 0, 0);
+       wq = alloc_workqueue("i1915-selftest", WQ_PERCPU, 0);
        if (wq == NULL)
                return -ENOMEM;
 

diff --git a/drivers/gpu/drm/i915/selftests/mock_gem_device.c b/drivers/gpu/drm/i915/selftests/mock_gem_device.c
index 210b9f8f7b611c65801b3e6d7cc1b82b334d28bb..27dc0e40a8d75c949f830d1f72ca200eba5d1992 100644 (file)
--- a/drivers/gpu/drm/i915/selftests/mock_gem_device.c
+++ b/drivers/gpu/drm/i915/selftests/mock_gem_device.c
@@ -223,7 +223,7 @@ struct drm_i915_private *mock_gem_device(void)
        if (!i915->wq)
                goto err_drv;
 
-       i915->unordered_wq = alloc_workqueue("mock-unordered", 0, 0);
+       i915->unordered_wq = alloc_workqueue("mock-unordered", WQ_PERCPU, 0);
        if (!i915->unordered_wq)
                goto err_wq;