Messages in this thread | | | Date | Wed, 30 Aug 2023 07:51:13 -1000 | From | Tejun Heo <> | Subject | Re: WQ_UNBOUND warning since recent workqueue refactoring |
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Hello,
(cc'ing i915 folks)
On Wed, Aug 30, 2023 at 04:57:42PM +0200, Heiner Kallweit wrote: > Recently I started to see the following warning on linux-next and presumably > this may be related to the refactoring of the workqueue core code. > > [ 56.900223] workqueue: output_poll_execute [drm_kms_helper] hogged CPU for >10000us 4 times, consider switching to WQ_UNBOUND > [ 56.923226] workqueue: i915_hpd_poll_init_work [i915] hogged CPU for >10000us 4 times, consider switching to WQ_UNBOUND > [ 97.860430] workqueue: output_poll_execute [drm_kms_helper] hogged CPU for >10000us 8 times, consider switching to WQ_UNBOUND > [ 97.884453] workqueue: i915_hpd_poll_init_work [i915] hogged CPU for >10000us 8 times, consider switching to WQ_UNBOUND > > Adding WQ_UNBOUND to these queues didn't change the behavior.
That should have made them go away as the code path isn't active at all for WQ_UNBOUND workqueues. Can you please double check?
> Maybe relevant: I run the affected system headless.
i915 folks, workqueue recently added debug warnings which trigger when a per-cpu work item hogs the CPU for too long - 10ms in this case. This is problematic because such work item can stall other per-cpu work items.
* Is it expected for the above two work functions to occupy the CPU for over 10ms repeatedly?
* If so, can we make them use an unbound workqueue instead?
Thanks.
-- tejun
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