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Message-ID: References: <20210818112114.1417685-1-Jingwen.Chen2@amd.com> <69cbf5bd-42c2-be55-a604-43f4ebba159d@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Operating-System: Linux phenom 5.10.0-7-amd64 X-BeenThere: amd-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Discussion list for AMD gfx List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: amd-gfx-bounces@lists.freedesktop.org Sender: "amd-gfx" On Wed, Aug 18, 2021 at 10:36:32AM -0400, Andrey Grodzovsky wrote: > > On 2021-08-18 10:32 a.m., Daniel Vetter wrote: > > On Wed, Aug 18, 2021 at 10:26:25AM -0400, Andrey Grodzovsky wrote: > > > On 2021-08-18 10:02 a.m., Alex Deucher wrote: > > > > > > > + dri-devel > > > > > > > > Since scheduler is a shared component, please add dri-devel on all > > > > scheduler patches. > > > > > > > > On Wed, Aug 18, 2021 at 7:21 AM Jingwen Chen wrote: > > > > > [Why] > > > > > for bailing job, this commit will delete it from pending list thus the > > > > > bailing job will never have a chance to be resubmitted even in advance > > > > > tdr mode. > > > > > > > > > > [How] > > > > > after embeded hw_fence into amdgpu_job is done, the race condition that > > > > > this commit tries to work around is completely solved.So revert this > > > > > commit. > > > > > This reverts commit 135517d3565b48f4def3b1b82008bc17eb5d1c90. > > > > > v2: > > > > > add dma_fence_get/put() around timedout_job to avoid concurrent delete > > > > > during processing timedout_job > > > > > > > > > > Signed-off-by: Jingwen Chen > > > > > --- > > > > > drivers/gpu/drm/scheduler/sched_main.c | 23 +++++------------------ > > > > > 1 file changed, 5 insertions(+), 18 deletions(-) > > > > > > > > > > diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c > > > > > index a2a953693b45..f9b9b3aefc4a 100644 > > > > > --- a/drivers/gpu/drm/scheduler/sched_main.c > > > > > +++ b/drivers/gpu/drm/scheduler/sched_main.c > > > > > @@ -314,6 +314,7 @@ static void drm_sched_job_timedout(struct work_struct *work) > > > > > { > > > > > struct drm_gpu_scheduler *sched; > > > > > struct drm_sched_job *job; > > > > > + struct dma_fence *fence; > > > > > enum drm_gpu_sched_stat status = DRM_GPU_SCHED_STAT_NOMINAL; > > > > > > > > > > sched = container_of(work, struct drm_gpu_scheduler, work_tdr.work); > > > > > @@ -325,11 +326,10 @@ static void drm_sched_job_timedout(struct work_struct *work) > > > > > > > > > > if (job) { > > > > > /* > > > > > - * Remove the bad job so it cannot be freed by concurrent > > > > > - * drm_sched_cleanup_jobs. It will be reinserted back after sched->thread > > > > > - * is parked at which point it's safe. > > > > > + * Get job->s_fence->parent here to avoid concurrent delete during > > > > > + * processing timedout_job > > > > > */ > > > > > - list_del_init(&job->list); > > > > > + fence = dma_fence_get(job->s_fence->parent); > > > > > > While this is true for amdgpu, it has no meaning for other drivers for whom > > > we haven't > > > done the refactoring of embedding HW fence (parent) into the job structure. > > > In fact thinking > > > about it, unless you do the HW fence embedding for all the drivers using the > > > scheduler you cannot > > > revert this patch or you will just break them. > > btw, why did you do that embedding? I do still have my patches with > > dma_fence annotations floating around, but my idea at least was to fix > > that issue with a mempool, not with embeddeding. What was the motivation > > for embedding the wh fence? > > -Daniel > > > The motivation was 2 fold, avoid memory allocation during jobs submissions > (HW fence allocation) because as Christian explained this leads to deadlock > with > mm code during evictions due to memory pressure (Christian can clarify if I > messed Yeah that's the exact same thing I've chased with my dma_fence annotations, but thus far zero to none interested in getting it sorted. I think it'd be good to have some cross-driver agreement on how this should be solved before someone just charges ahead ... > this explanation). Second is to exactly revert this patch because while it > solved the issue > described in the patch it created another with drivers who baildc out early > during TDR handling > for various reason and the job would just leak because it was already > removed form pending list. Can't we reinsert it before we restart the scheduler thread? It might need a separate list for that due to the lockless queue tricks. Or am I thinking about the wrong kind of "we lost the job"? -Danile > > Andrey > > > > > > > > > Andrey > > > > > > > > > > > spin_unlock(&sched->job_list_lock); > > > > > > > > > > status = job->sched->ops->timedout_job(job); > > > > > @@ -342,6 +342,7 @@ static void drm_sched_job_timedout(struct work_struct *work) > > > > > job->sched->ops->free_job(job); > > > > > sched->free_guilty = false; > > > > > } > > > > > + dma_fence_put(fence); > > > > > } else { > > > > > spin_unlock(&sched->job_list_lock); > > > > > } > > > > > @@ -392,20 +393,6 @@ void drm_sched_stop(struct drm_gpu_scheduler *sched, struct drm_sched_job *bad) > > > > > > > > > > kthread_park(sched->thread); > > > > > > > > > > - /* > > > > > - * Reinsert back the bad job here - now it's safe as > > > > > - * drm_sched_get_cleanup_job cannot race against us and release the > > > > > - * bad job at this point - we parked (waited for) any in progress > > > > > - * (earlier) cleanups and drm_sched_get_cleanup_job will not be called > > > > > - * now until the scheduler thread is unparked. > > > > > - */ > > > > > - if (bad && bad->sched == sched) > > > > > - /* > > > > > - * Add at the head of the queue to reflect it was the earliest > > > > > - * job extracted. > > > > > - */ > > > > > - list_add(&bad->list, &sched->pending_list); > > > > > - > > > > > /* > > > > > * Iterate the job list from later to earlier one and either deactive > > > > > * their HW callbacks or remove them from pending list if they already > > > > > -- > > > > > 2.25.1 > > > > > -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch