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drm/scheduler: rework job destruction

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We now destroy finished jobs from the worker thread to make sure that
we never destroy a job currently in timeout processing.
By this we avoid holding lock around ring mirror list in drm_sched_stop
which should solve a deadlock reported by a user.

v2: Remove unused variable.
v4: Move guilty job free into sched code.
v5:
Move sched->hw_rq_count to drm_sched_start to account for counter
decrement in drm_sched_stop even when we don't call resubmit jobs
if guily job did signal.
v6: remove unused variable

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=109692

Acked-by: Chunming Zhou <david1.zhou@amd.com>
Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1555599624-12285-3-git-send-email-andrey.grodzovsky@amd.com
This commit is contained in:
Christian König
2019-04-18 11:00:21 -04:00
committed by Alex Deucher
parent b3198c38f0
commit 5918045c4e
8 changed files with 102 additions and 85 deletions
Download Patch File Download Diff File Expand all files Collapse all files

159
drivers/gpu/drm/scheduler/sched_main.c
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@@ -265,32 +265,6 @@ void drm_sched_resume_timeout(struct drm_gpu_scheduler *sched,
}
EXPORT_SYMBOL(drm_sched_resume_timeout);
/* job_finish is called after hw fence signaled
*/
static void drm_sched_job_finish(struct work_struct *work)
{
struct drm_sched_job *s_job = container_of(work, struct drm_sched_job,
finish_work);
struct drm_gpu_scheduler *sched = s_job->sched;
unsigned long flags;
/*
* Canceling the timeout without removing our job from the ring mirror
* list is safe, as we will only end up in this worker if our jobs
* finished fence has been signaled. So even if some another worker
* 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(&sched->work_tdr);
spin_lock_irqsave(&sched->job_list_lock, flags);
/* queue TDR for next job */
drm_sched_start_timeout(sched);
spin_unlock_irqrestore(&sched->job_list_lock, flags);
sched->ops->free_job(s_job);
}
static void drm_sched_job_begin(struct drm_sched_job *s_job)
{
struct drm_gpu_scheduler *sched = s_job->sched;
@@ -315,6 +289,13 @@ static void drm_sched_job_timedout(struct work_struct *work)
if (job)
job->sched->ops->timedout_job(job);
/*
* Guilty job did complete and hence needs to be manually removed
* See drm_sched_stop doc.
*/
if (list_empty(&job->node))
job->sched->ops->free_job(job);
spin_lock_irqsave(&sched->job_list_lock, flags);
drm_sched_start_timeout(sched);
spin_unlock_irqrestore(&sched->job_list_lock, flags);
@@ -371,23 +352,26 @@ EXPORT_SYMBOL(drm_sched_increase_karma);
* @sched: scheduler instance
* @bad: bad scheduler job
*
* Stop the scheduler and also removes and frees all completed jobs.
* Note: bad job will not be freed as it might be used later and so it's
* callers responsibility to release it manually if it's not part of the
* mirror list any more.
*
*/
void drm_sched_stop(struct drm_gpu_scheduler *sched)
void drm_sched_stop(struct drm_gpu_scheduler *sched, struct drm_sched_job *bad)
{
struct drm_sched_job *s_job;
struct drm_sched_job *s_job, *tmp;
unsigned long flags;
struct dma_fence *last_fence = NULL;
kthread_park(sched->thread);
/*
* Verify all the signaled jobs in mirror list are removed from the ring
* by waiting for the latest job to enter the list. This should insure that
* also all the previous jobs that were in flight also already singaled
* and removed from the list.
* Iterate the job list from later to earlier one and either deactive
* their HW callbacks or remove them from mirror list if they already
* signaled.
* This iteration is thread safe as sched thread is stopped.
*/
spin_lock_irqsave(&sched->job_list_lock, flags);
list_for_each_entry_reverse(s_job, &sched->ring_mirror_list, node) {
list_for_each_entry_safe_reverse(s_job, tmp, &sched->ring_mirror_list, node) {
if (s_job->s_fence->parent &&
dma_fence_remove_callback(s_job->s_fence->parent,
&s_job->cb)) {
@@ -395,15 +379,29 @@ void drm_sched_stop(struct drm_gpu_scheduler *sched)
s_job->s_fence->parent = NULL;
atomic_dec(&sched->hw_rq_count);
} else {
last_fence = dma_fence_get(&s_job->s_fence->finished);
break;
}
}
spin_unlock_irqrestore(&sched->job_list_lock, flags);
/*
* remove job from ring_mirror_list.
* Locking here is for concurrent resume timeout
*/
spin_lock_irqsave(&sched->job_list_lock, flags);
list_del_init(&s_job->node);
spin_unlock_irqrestore(&sched->job_list_lock, flags);
if (last_fence) {
dma_fence_wait(last_fence, false);
dma_fence_put(last_fence);
/*
* Wait for job's HW fence callback to finish using s_job
* before releasing it.
*
* Job is still alive so fence refcount at least 1
*/
dma_fence_wait(&s_job->s_fence->finished, false);
/*
* We must keep bad job alive for later use during
* recovery by some of the drivers
*/
if (bad != s_job)
sched->ops->free_job(s_job);
}
}
}
@@ -418,21 +416,22 @@ EXPORT_SYMBOL(drm_sched_stop);
void drm_sched_start(struct drm_gpu_scheduler *sched, bool full_recovery)
{
struct drm_sched_job *s_job, *tmp;
unsigned long flags;
int r;
if (!full_recovery)
goto unpark;
/*
* Locking the list is not required here as the sched thread is parked
* so no new jobs are being pushed in to HW and in drm_sched_stop we
* flushed all the jobs who were still in mirror list but who already
* signaled and removed them self from the list. Also concurrent
* so no new jobs are being inserted or removed. Also concurrent
* GPU recovers can't run in parallel.
*/
list_for_each_entry_safe(s_job, tmp, &sched->ring_mirror_list, node) {
struct dma_fence *fence = s_job->s_fence->parent;
atomic_inc(&sched->hw_rq_count);
if (!full_recovery)
continue;
if (fence) {
r = dma_fence_add_callback(fence, &s_job->cb,
drm_sched_process_job);
@@ -445,9 +444,12 @@ void drm_sched_start(struct drm_gpu_scheduler *sched, bool full_recovery)
drm_sched_process_job(NULL, &s_job->cb);
}
drm_sched_start_timeout(sched);
if (full_recovery) {
spin_lock_irqsave(&sched->job_list_lock, flags);
drm_sched_start_timeout(sched);
spin_unlock_irqrestore(&sched->job_list_lock, flags);
}
unpark:
kthread_unpark(sched->thread);
}
EXPORT_SYMBOL(drm_sched_start);
@@ -464,7 +466,6 @@ void drm_sched_resubmit_jobs(struct drm_gpu_scheduler *sched)
uint64_t guilty_context;
bool found_guilty = false;
/*TODO DO we need spinlock here ? */
list_for_each_entry_safe(s_job, tmp, &sched->ring_mirror_list, node) {
struct drm_sched_fence *s_fence = s_job->s_fence;
@@ -477,7 +478,6 @@ void drm_sched_resubmit_jobs(struct drm_gpu_scheduler *sched)
dma_fence_set_error(&s_fence->finished, -ECANCELED);
s_job->s_fence->parent = sched->ops->run_job(s_job);
atomic_inc(&sched->hw_rq_count);
}
}
EXPORT_SYMBOL(drm_sched_resubmit_jobs);
@@ -514,7 +514,6 @@ int drm_sched_job_init(struct drm_sched_job *job,
return -ENOMEM;
job->id = atomic64_inc_return(&sched->job_id_count);
INIT_WORK(&job->finish_work, drm_sched_job_finish);
INIT_LIST_HEAD(&job->node);
return 0;
@@ -597,24 +596,53 @@ static void drm_sched_process_job(struct dma_fence *f, struct dma_fence_cb *cb)
struct drm_sched_job *s_job = container_of(cb, struct drm_sched_job, cb);
struct drm_sched_fence *s_fence = s_job->s_fence;
struct drm_gpu_scheduler *sched = s_fence->sched;
unsigned long flags;
cancel_delayed_work(&sched->work_tdr);
atomic_dec(&sched->hw_rq_count);
atomic_dec(&sched->num_jobs);
spin_lock_irqsave(&sched->job_list_lock, flags);
/* remove job from ring_mirror_list */
list_del_init(&s_job->node);
spin_unlock_irqrestore(&sched->job_list_lock, flags);
trace_drm_sched_process_job(s_fence);
drm_sched_fence_finished(s_fence);
trace_drm_sched_process_job(s_fence);
wake_up_interruptible(&sched->wake_up_worker);
}
/**
* drm_sched_cleanup_jobs - destroy finished jobs
*
* @sched: scheduler instance
*
* Remove all finished jobs from the mirror list and destroy them.
*/
static void drm_sched_cleanup_jobs(struct drm_gpu_scheduler *sched)
{
unsigned long flags;
/* Don't destroy jobs while the timeout worker is running */
if (!cancel_delayed_work(&sched->work_tdr))
return;
while (!list_empty(&sched->ring_mirror_list)) {
struct drm_sched_job *job;
job = list_first_entry(&sched->ring_mirror_list,
struct drm_sched_job, node);
if (!dma_fence_is_signaled(&job->s_fence->finished))
break;
spin_lock_irqsave(&sched->job_list_lock, flags);
/* remove job from ring_mirror_list */
list_del_init(&job->node);
spin_unlock_irqrestore(&sched->job_list_lock, flags);
sched->ops->free_job(job);
}
/* queue timeout for next job */
spin_lock_irqsave(&sched->job_list_lock, flags);
drm_sched_start_timeout(sched);
spin_unlock_irqrestore(&sched->job_list_lock, flags);
schedule_work(&s_job->finish_work);
}
/**
@@ -656,9 +684,10 @@ static int drm_sched_main(void *param)
struct dma_fence *fence;
wait_event_interruptible(sched->wake_up_worker,
(drm_sched_cleanup_jobs(sched),
(!drm_sched_blocked(sched) &&
(entity = drm_sched_select_entity(sched))) ||
kthread_should_stop());
kthread_should_stop()));
if (!entity)
continue;