Am 04.10.2018 um 18:32 schrieb Nayan Deshmukh:
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.
That is a bug a swell.
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.
Actually I wanted to completely rework that part since it is rather
unreliable as well.
Considering how buggy all of that is and how important it is to get it
right I think I will rather do it myself.
Regards,
Christian.
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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