On Wed, Apr 13, 2022 at 8:05 AM Dmitry Osipenko <dmitry.osipenko@xxxxxxxxxxxxx> wrote: > > On 4/13/22 01:59, Erico Nunes wrote: > > On Tue, Apr 12, 2022 at 9:41 PM Andrey Grodzovsky > > <andrey.grodzovsky@xxxxxxx> wrote: > >> > >> > >> On 2022-04-12 14:20, Dmitry Osipenko wrote: > >>> On 4/12/22 19:51, Andrey Grodzovsky wrote: > >>>> On 2022-04-11 18:15, Dmitry Osipenko wrote: > >>>>> Interrupt context can't sleep. Drivers like Panfrost and MSM are taking > >>>>> mutex when job is released, and thus, that code can sleep. This results > >>>>> into "BUG: scheduling while atomic" if locks are contented while job is > >>>>> freed. There is no good reason for releasing scheduler's jobs in IRQ > >>>>> context, hence use normal context to fix the trouble. > >>>> > >>>> I am not sure this is the beast Idea to leave job's sw fence signalling > >>>> to be > >>>> executed in system_wq context which is prone to delays of executing > >>>> various work items from around the system. Seems better to me to leave the > >>>> fence signaling within the IRQ context and offload only the job freeing or, > >>>> maybe handle rescheduling to thread context within drivers implemention > >>>> of .free_job cb. Not really sure which is the better. > >>> We're talking here about killing jobs when driver destroys context, > >>> which doesn't feel like it needs to be a fast path. I could move the > >>> signalling into drm_sched_entity_kill_jobs_cb() and use unbound wq, but > >>> do we really need this for a slow path? > >> > >> > >> You can't move the signaling back to drm_sched_entity_kill_jobs_cb > >> since this will bring back the lockdep splat that 'drm/sched: Avoid > >> lockdep spalt on killing a processes' > >> was fixing. > >> > >> I see your point and i guess we can go this way too. Another way would > >> be to add to > >> panfrost and msm job a work_item and reschedule to thread context from > >> within their > >> .free_job callbacks but that probably to cumbersome to be justified here. > > > > FWIW since this mentioned individual drivers, commit 'drm/sched: Avoid > > lockdep spalt on killing a processes' also introduced problems for > > lima. > > There were some occurrences in our CI > > https://gitlab.freedesktop.org/mesa/mesa/-/jobs/20980982/raw . > > Later I found it also reproducible on normal usage when just closing > > applications, so it may be affecting users too. > > > > I tested this patch and looks like it fixes things for lima. > > This patch indeed should fix that lima bug. Feel free to give yours > tested-by :) Sure: Tested-by: Erico Nunes <nunes.erico@xxxxxxxxx> Thanks Erico
