On 2023-06-21 10:53, Boris Brezillon wrote: > On Wed, 21 Jun 2023 10:41:22 -0400 > Luben Tuikov <luben.tuikov@xxxxxxx> wrote: > >> On 2023-06-21 10:18, Boris Brezillon wrote: >>> Hello Luben, >>> >>> On Wed, 21 Jun 2023 09:56:40 -0400 >>> Luben Tuikov <luben.tuikov@xxxxxxx> wrote: >>> >>>> On 2023-06-19 03:19, Boris Brezillon wrote: >>>>> drm_sched_entity_kill_jobs_cb() logic is omitting the last fence popped >>>>> from the dependency array that was waited upon before >>>>> drm_sched_entity_kill() was called (drm_sched_entity::dependency field), >>>>> so we're basically waiting for all dependencies except one. >>>>> >>>>> In theory, this wait shouldn't be needed because resources should have >>>>> their users registered to the dma_resv object, thus guaranteeing that >>>>> future jobs wanting to access these resources wait on all the previous >>>>> users (depending on the access type, of course). But we want to keep >>>>> these explicit waits in the kill entity path just in case. >>>>> >>>>> Let's make sure we keep all dependencies in the array in >>>>> drm_sched_job_dependency(), so we can iterate over the array and wait >>>>> in drm_sched_entity_kill_jobs_cb(). >>>>> >>>>> We also make sure we wait on drm_sched_fence::finished if we were >>>>> originally asked to wait on drm_sched_fence::scheduled. In that case, >>>>> we assume the intent was to delegate the wait to the firmware/GPU or >>>>> rely on the pipelining done at the entity/scheduler level, but when >>>>> killing jobs, we really want to wait for completion not just scheduling. >>>>> >>>>> v6: >>>>> - Back to v4 implementation >>>>> - Add Christian's R-b >>>>> >>>>> v5: >>>>> - Flag deps on which we should only wait for the scheduled event >>>>> at insertion time >>>>> >>>>> v4: >>>>> - Fix commit message >>>>> - Fix a use-after-free bug >>>>> >>>>> v3: >>>>> - Always wait for drm_sched_fence::finished fences in >>>>> drm_sched_entity_kill_jobs_cb() when we see a sched_fence >>>>> >>>>> v2: >>>>> - Don't evict deps in drm_sched_job_dependency() >>>> >>>> Hmm, why is this in reverse chronological order? >>>> It's very confusing. >>> >>> Dunno, that's how I've always ordered things, and quick look at some >>> dri-devel patches [1][2] makes me think I'm not the only one to start >>> from the latest submission. >>> >>> [1]https://lkml.org/lkml/2023/6/19/941 >>> [2]https://lore.kernel.org/dri-devel/cover.1686729444.git.Sandor.yu@xxxxxxx/T/#t >>> >>>> >>>>> >>>>> Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx> >>>>> Suggested-by: "Christian König" <christian.koenig@xxxxxxx> >>>>> Reviewed-by: "Christian König" <christian.koenig@xxxxxxx> >>>> >>>> These three lines would usually come after the CCs. >>> >>> Again, I think I've always inserted those tags before the Cc, but I can >>> re-order things if you prefer. Let me know if you want me to send a v7 >>> addressing the Cc+changelog ordering. >> >> No, it's not necessary for this patch, but in the future I'd rather follow >> chronological ordering for the versions, and in the Cc list. It's similar >> to how the patch description follows (narrative text) and to how we reply >> back to emails, and prevalently in the kernel log in drm ("git log" should >> suffice). >> >> Reading in chronological progression builds a narrative, a picture, in one's >> mind and makes it easy to see justifications for said narrative, or see reasons >> to change the narrative. >> >> That is, one can make a better decision knowing the full history, rather than >> only the latest change. >> >> (And in fact when I read the version revision list, my eyes skip over v[X] >> and just read down, so I was wondering why and how Christian R-B the patch >> in v2, and it wasn't until I actually saw that they were ordered in reverse >> chronological order, which was in fact v6--listed first, which I'd assumed >> was listed last.) >> >> Do you have access or do you know who is pushing this patch to drm-misc-fixes? > > I can push it. > Acked-by: Luben Tuikov <luben.tuikov@xxxxxxx> Regards, Luben
