Hi Christian,
On Thu, Sep 27, 2018 at 12:55 AM Nayan Deshmukh
<nayan26deshmukh@xxxxxxxxx> wrote:
>
> Hi Christian,
>
>
> On Wed, Sep 26, 2018, 10:13 AM Christian König <ckoenig.leichtzumerken@xxxxxxxxx> wrote:
>>
>> Am 26.09.2018 um 09:39 schrieb Lucas Stach:
>> > Hi Nayan,
>> >
>> > Am Mittwoch, den 26.09.2018, 02:09 +0900 schrieb Nayan Deshmukh:
>> >> having a delayed work item per job is redundant as we only need one
>> >> per scheduler to track the time out the currently executing job.
>> >>
>> >> v2: the first element of the ring mirror list is the currently
>> >> executing job so we don't need a additional variable for it
>> >>
>> >> Signed-off-by: Nayan Deshmukh <nayan26deshmukh@xxxxxxxxx>
>> >> Suggested-by: Christian König <christian.koenig@xxxxxxx>
>> >> ---
>> >> drivers/gpu/drm/scheduler/sched_main.c | 31 ++++++++++++++++---------------
>> >> include/drm/gpu_scheduler.h | 6 +++---
>> >> 2 files changed, 19 insertions(+), 18 deletions(-)
>> >>
>> >> diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
>> >> index 9ca741f3a0bc..4e8505d51795 100644
>> >> --- a/drivers/gpu/drm/scheduler/sched_main.c
>> >> +++ b/drivers/gpu/drm/scheduler/sched_main.c
>> >> @@ -197,19 +197,15 @@ static void drm_sched_job_finish(struct work_struct *work)
>> >> * manages to find this job as the next job in the list, the fence
>> >> * signaled check below will prevent the timeout to be restarted.
>> >> */
>> >> - cancel_delayed_work_sync(&s_job->work_tdr);
>> >> + cancel_delayed_work_sync(&sched->work_tdr);
>> >>
>> >> spin_lock(&sched->job_list_lock);
>> >> - /* queue TDR for next job */
>> >> - if (sched->timeout != MAX_SCHEDULE_TIMEOUT &&
>> >> - !list_is_last(&s_job->node, &sched->ring_mirror_list)) {
>> >> - struct drm_sched_job *next = list_next_entry(s_job, node);
>> >> -
>> >> - if (!dma_fence_is_signaled(&next->s_fence->finished))
>> >> - schedule_delayed_work(&next->work_tdr, sched->timeout);
>> >> - }
>> >> /* remove job from ring_mirror_list */
>> >> list_del(&s_job->node);
>> >> + /* queue TDR for next job */
>> >> + if (sched->timeout != MAX_SCHEDULE_TIMEOUT &&
>> >> + !list_empty(&sched->ring_mirror_list))
>> >> + schedule_delayed_work(&sched->work_tdr, sched->timeout);
>> >> spin_unlock(&sched->job_list_lock);
>> >>
>> >> dma_fence_put(&s_job->s_fence->finished);
>> >> @@ -236,16 +232,21 @@ static void drm_sched_job_begin(struct drm_sched_job *s_job)
>> >> if (sched->timeout != MAX_SCHEDULE_TIMEOUT &&
>> >> list_first_entry_or_null(&sched->ring_mirror_list,
>> >> struct drm_sched_job, node) == s_job)
>> >> - schedule_delayed_work(&s_job->work_tdr, sched->timeout);
>> >> + schedule_delayed_work(&sched->work_tdr, sched->timeout);
>> >> spin_unlock(&sched->job_list_lock);
>> >> }
>> >>
>> >> static void drm_sched_job_timedout(struct work_struct *work)
>> >> {
>> >> - struct drm_sched_job *job = container_of(work, struct drm_sched_job,
>> >> - work_tdr.work);
>> >> + struct drm_gpu_scheduler *sched;
>> >> + struct drm_sched_job *job;
>> >> +
>> >> + sched = container_of(work, struct drm_gpu_scheduler, work_tdr.work);
>> >> + job = list_first_entry_or_null(&sched->ring_mirror_list,
>> >> + struct drm_sched_job, node);
>> >>
>> >> - job->sched->ops->timedout_job(job);
>> >> + if (job)
>> >> + job->sched->ops->timedout_job(job);
>> > I don't think this is fully robust. Jobs are only removed from the
>> > ring_mirror_list once the job_finish worker has run. If execution of
>> > this worker is delayed for any reason (though it's really unlikely for
>> > a delay as long as the job timeout to happen) you are blaming the wrong
>> > job here.
>> >
>> > So I think what you need to to is find the first job in the ring mirror
>> > list with an unsignaled finish fence to robustly find the stuck job.
>>
>> Yeah, that is a known problem I've pointed out as well.
>>
>> The issue is we have bug reports that this happened before the patch,
>> but I'm not 100% sure how.
>>
>> My suggestion is to move a good part of the logic from
>> drm_sched_hw_job_reset() and drm_sched_job_recovery() into
>> drm_sched_job_timedout().
>>
>> E.g. we first call dma_fence_remove_callback() for each job and actually
>> check the return value if the fence was already signaled.
>>
We can move this part to drm_sched_job_timedout().
>> If we find a signaled fence we abort and add the callback back to the
>> ones where we removed it.
>>
I was not able to find the abort part. In drm_sched_hw_job_reset() we
don't take a action if the parent fence was already signaled.
We cannot shift a lot from drm_sched_job_recovery() to
drm_sched_job_timedout(). The only part that seems shiftable is the
one where we cancel the guilty job.
Regards,
Nayan
>> Nayan do you want to take care of this or should I take a look?
>
> I can take care of it.
>
> Regards,
> Nayan
>>
>>
>> Regards,
>> Christian.
>>
>> >
>> > Regards,
>> > Lucas
>> >
>> >> }
>> >>
>> >> /**
>> >> @@ -315,7 +316,7 @@ void drm_sched_job_recovery(struct drm_gpu_scheduler *sched)
>> >> s_job = list_first_entry_or_null(&sched->ring_mirror_list,
>> >> struct drm_sched_job, node);
>> >> if (s_job && sched->timeout != MAX_SCHEDULE_TIMEOUT)
>> >> - schedule_delayed_work(&s_job->work_tdr, sched->timeout);
>> >> + schedule_delayed_work(&sched->work_tdr, sched->timeout);
>> >>
>> >> list_for_each_entry_safe(s_job, tmp, &sched->ring_mirror_list, node) {
>> >> struct drm_sched_fence *s_fence = s_job->s_fence;
>> >> @@ -384,7 +385,6 @@ int drm_sched_job_init(struct drm_sched_job *job,
>> >>
>> >> INIT_WORK(&job->finish_work, drm_sched_job_finish);
>> >> INIT_LIST_HEAD(&job->node);
>> >> - INIT_DELAYED_WORK(&job->work_tdr, drm_sched_job_timedout);
>> >>
>> >> return 0;
>> >> }
>> >> @@ -575,6 +575,7 @@ int drm_sched_init(struct drm_gpu_scheduler *sched,
>> >> INIT_LIST_HEAD(&sched->ring_mirror_list);
>> >> spin_lock_init(&sched->job_list_lock);
>> >> atomic_set(&sched->hw_rq_count, 0);
>> >> + INIT_DELAYED_WORK(&sched->work_tdr, drm_sched_job_timedout);
>> >> atomic_set(&sched->num_jobs, 0);
>> >> atomic64_set(&sched->job_id_count, 0);
>> >>
>> >> diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h
>> >> index daec50f887b3..d87b268f1781 100644
>> >> --- a/include/drm/gpu_scheduler.h
>> >> +++ b/include/drm/gpu_scheduler.h
>> >> @@ -175,8 +175,6 @@ struct drm_sched_fence *to_drm_sched_fence(struct dma_fence *f);
>> >> * finished to remove the job from the
>> >> * @drm_gpu_scheduler.ring_mirror_list.
>> >> * @node: used to append this struct to the @drm_gpu_scheduler.ring_mirror_list.
>> >> - * @work_tdr: schedules a delayed call to @drm_sched_job_timedout after the timeout
>> >> - * interval is over.
>> >> * @id: a unique id assigned to each job scheduled on the scheduler.
>> >> * @karma: increment on every hang caused by this job. If this exceeds the hang
>> >> * limit of the scheduler then the job is marked guilty and will not
>> >> @@ -195,7 +193,6 @@ struct drm_sched_job {
>> >> struct dma_fence_cb finish_cb;
>> >> struct work_struct finish_work;
>> >> struct list_head node;
>> >> - struct delayed_work work_tdr;
>> >> uint64_t id;
>> >> atomic_t karma;
>> >> enum drm_sched_priority s_priority;
>> >> @@ -259,6 +256,8 @@ struct drm_sched_backend_ops {
>> >> * finished.
>> >> * @hw_rq_count: the number of jobs currently in the hardware queue.
>> >> * @job_id_count: used to assign unique id to the each job.
>> >> + * @work_tdr: schedules a delayed call to @drm_sched_job_timedout after the
>> >> + * timeout interval is over.
>> >> * @thread: the kthread on which the scheduler which run.
>> >> * @ring_mirror_list: the list of jobs which are currently in the job queue.
>> >> * @job_list_lock: lock to protect the ring_mirror_list.
>> >> @@ -278,6 +277,7 @@ struct drm_gpu_scheduler {
>> >> wait_queue_head_t job_scheduled;
>> >> atomic_t hw_rq_count;
>> >> atomic64_t job_id_count;
>> >> + struct delayed_work work_tdr;
>> >> struct task_struct *thread;
>> >> struct list_head ring_mirror_list;
>> >> spinlock_t job_list_lock;
>> > _______________________________________________
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>> > dri-devel@xxxxxxxxxxxxxxxxxxxxx
>> > https://lists.freedesktop.org/mailman/listinfo/dri-devel
>>
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