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 <[email protected]>
Signed-off-by: Marco Crivellari <[email protected]>
---
drivers/gpu/drm/i915/display/intel_display_driver.c | 4 ++--
drivers/gpu/drm/i915/i915_driver.c | 3 ++-
drivers/gpu/drm/i915/selftests/i915_sw_fence.c | 2 +-
drivers/gpu/drm/i915/selftests/mock_gem_device.c | 2 +-
4 files changed, 6 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_display_driver.c
b/drivers/gpu/drm/i915/display/intel_display_driver.c
index cf1c14412abe..e12f9126b155 100644
--- a/drivers/gpu/drm/i915/display/intel_display_driver.c
+++ b/drivers/gpu/drm/i915/display/intel_display_driver.c
@@ -257,13 +257,13 @@ 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 0f33cdc11736..380cb20a47c6 100644
--- a/drivers/gpu/drm/i915/i915_driver.c
+++ b/drivers/gpu/drm/i915/i915_driver.c
@@ -143,7 +143,8 @@ 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 8f5ce71fa453..b81d65c77458 100644
--- 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 fb8751bd5df0..684e6ca0f960 100644
--- a/drivers/gpu/drm/i915/selftests/mock_gem_device.c
+++ b/drivers/gpu/drm/i915/selftests/mock_gem_device.c
@@ -221,7 +221,7 @@ 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;
--
2.51.1
