On 25/09/2019 15:12, Koenig, Christian wrote:
Am 25.09.19 um 16:06 schrieb Steven Price:
On 24/09/2019 10:55, Koenig, Christian wrote:
Sorry for the delayed response, have been busy on other stuff last week.
Am 17.09.19 um 14:46 schrieb Steven Price:
On 17/09/2019 09:42, Koenig, Christian wrote:
Hi Steven,
thought about that issue a bit more and I think I came up with a solution.
What you could do is to split up drm_sched_cleanup_jobs() into two functions.
One that checks if jobs to be cleaned up are present and one which does the actual cleanup.
This way we could call drm_sched_cleanup_jobs() outside of the wait_event_interruptible().
Yes that seems like a good solution - there doesn't seem to be a good reason why the actual job cleanup needs to be done within the wait_event_interruptible() condition. I did briefly attempt that before, but I couldn't work out exactly what the condition is which should cause the wake (my initial attempt caused continuous wake-ups).
Basically you need something like the following:
- Test is timeout worker is running:
if (sched->timeout != MAX_SCHEDULE_TIMEOUT && !cancel_delayed_work(&sched->work_tdr)) return false;
- Test if there is any job ready to be cleaned up.
job = list_first_entry_or_null(&sched->ring_mirror_list, struct drm_sched_job, node); if (!job || !dma_fence_is_signaled(&job->s_fence->finished)) return false;
That should basically do it.
Thanks for the pointers. I wasn't sure if the "queue timeout for next job" part was necessary or not if step 2 above returns false.
I've been testing the following patch which simply pulls the sched->ops->free_job() out of the wait_event_interruptible().
I'll try with just the tests you've described.
It looks like it is necessary to queue the timeout for the next job even if there isn't a job to be cleaned up (i.e. even if we wouldn't exit from wait_event_interruptible(). So I'll go with a patch like below.
----8<----- From 873c1816394beee72904e64aa2ee0f169e768d76 Mon Sep 17 00:00:00 2001 From: Steven Price steven.price@arm.com Date: Mon, 23 Sep 2019 11:08:50 +0100 Subject: [PATCH] drm: Don't free jobs in wait_event_interruptible()
drm_sched_cleanup_jobs() attempts to free finished jobs, however because it is called as the condition of wait_event_interruptible() it must not sleep. Unfortuantly some free callbacks (notibly for Panfrost) do sleep.
Instead let's rename drm_sched_cleanup_jobs() to drm_sched_get_cleanup_job() and simply return a job for processing if there is one. The caller can then call the free_job() callback outside the wait_event_interruptible() where sleeping is possible before re-checking and returning to sleep if necessary.
Signed-off-by: Steven Price steven.price@arm.com
drivers/gpu/drm/scheduler/sched_main.c | 22 +++++++++++++++------- 1 file changed, 15 insertions(+), 7 deletions(-)
diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c index 9a0ee74d82dc..bf9b4931ddfd 100644 --- a/drivers/gpu/drm/scheduler/sched_main.c +++ b/drivers/gpu/drm/scheduler/sched_main.c @@ -622,20 +622,21 @@ static void drm_sched_process_job(struct dma_fence *f, struct dma_fence_cb *cb) }
/**
- drm_sched_cleanup_jobs - destroy finished jobs
- drm_sched_get_cleanup_job - fetch the next finished job to be destroyed
- @sched: scheduler instance
- Remove all finished jobs from the mirror list and destroy them.
- Returns the next finished job from the mirror list (if there is one)
*/
- ready for it to be destroyed.
-static void drm_sched_cleanup_jobs(struct drm_gpu_scheduler *sched) +static struct drm_sched_job *drm_sched_get_cleanup_job(struct drm_gpu_scheduler *sched) { unsigned long flags;
/* Don't destroy jobs while the timeout worker is running */ if (sched->timeout != MAX_SCHEDULE_TIMEOUT && !cancel_delayed_work(&sched->work_tdr))
return;
return NULL;while (!list_empty(&sched->ring_mirror_list)) {
Yeah, you should probably clean that up a bit here, but apart from that this should work as well.
Good point - this function can be tidied up quite a bit, I'll post a new patch shortly.
Thanks,
Steve
Regards, Christian.
@@ -651,7 +652,7 @@ static void drm_sched_cleanup_jobs(struct drm_gpu_scheduler *sched) list_del_init(&job->node); spin_unlock_irqrestore(&sched->job_list_lock, flags);
sched->ops->free_job(job);
return job;}
/* queue timeout for next job */
@@ -659,6 +660,7 @@ static void drm_sched_cleanup_jobs(struct drm_gpu_scheduler *sched) drm_sched_start_timeout(sched); spin_unlock_irqrestore(&sched->job_list_lock, flags);
return NULL; }
/**
@@ -698,12 +700,18 @@ static int drm_sched_main(void *param) struct drm_sched_fence *s_fence; struct drm_sched_job *sched_job; struct dma_fence *fence;
struct drm_sched_job *cleanup_job = NULL;wait_event_interruptible(sched->wake_up_worker,
(drm_sched_cleanup_jobs(sched),
(cleanup_job = drm_sched_get_cleanup_job(sched)) || (!drm_sched_blocked(sched) && (entity = drm_sched_select_entity(sched))) ||
kthread_should_stop()));
kthread_should_stop());while (cleanup_job) {sched->ops->free_job(cleanup_job);cleanup_job = drm_sched_get_cleanup_job(sched);}if (!entity) continue;
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