Re: [PATCH v2 2/6] drm/sched: Prevent teardown waitque from blocking too long

[Tvrtko Ursulin]

On 16/05/2025 10:53, Danilo Krummrich wrote:
> On Fri, May 16, 2025 at 10:33:30AM +0100, Tvrtko Ursulin wrote:
> > On 24/04/2025 10:55, Philipp Stanner wrote:
> > > +	 * @kill_fence_context: kill the fence context belonging to this scheduler
> >
> > Which fence context would that be? ;)
>
> There's one one per ring and a scheduler instance represents a single ring. So,
> what should be specified here?

I was pointing out the fact not all drivers are 1:1 sched:entity. So 
plural at least. Thought it would be obvious from the ";)".

> > Also, "fence context" would be a new terminology in gpu_scheduler.h API
> > level. You could call it ->sched_fini() or similar to signify at which point
> > in the API it gets called and then the fact it takes sched as parameter
> > would be natural.
>
> The driver should tear down the fence context in this callback, not the while
> scheduler. ->sched_fini() would hence be misleading.

Not the while what? Not while drm_sched_fini()? Could call it 
sched_kill() or anything. My point is that we dont' have "fence context" 
in the API but entities so adding a new term sounds sub-optimal.

> > We also probably want some commentary on the topic of indefinite (or very
> > long at least) blocking a thread exit / SIGINT/TERM/KILL time.
>
> You mean in case the driver does implement the callback, but does *not* properly
> tear down the fence context? So, you ask for describing potential consequences
> of drivers having bugs in the implementation of the callback? Or something else?

I was proposing the kerneldoc for the vfunc should document the callback 
must not block, or if blocking is unavoidable, either document a 
guideline on how long is acceptable. Maybe even enforce a limit in the 
scheduler core itself.

Regards,

Tvrtko