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.
