* [PATCH v2] drm: Don't free jobs in wait_event_interruptible()
@ 2019-09-26 9:54 Steven Price
2019-09-26 12:30 ` Steven Price
0 siblings, 1 reply; 2+ messages in thread
From: Steven Price @ 2019-09-26 9:54 UTC (permalink / raw)
To: Daniel Vetter, David Airlie, Christian König
Cc: Steven Price, dri-devel, linux-kernel, Alex Deucher,
Andrey Grodzovsky, Nayan Deshmukh, Sharat Masetty
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>
---
Changes from v1:
* Move list_first_entry_or_null() within the lock
drivers/gpu/drm/scheduler/sched_main.c | 44 ++++++++++++++------------
1 file changed, 24 insertions(+), 20 deletions(-)
diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
index 9a0ee74d82dc..0ed4aaa4e6d1 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -622,43 +622,41 @@ 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)
{
+ struct drm_sched_job *job = NULL;
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;
-
-
- while (!list_empty(&sched->ring_mirror_list)) {
- struct drm_sched_job *job;
+ return NULL;
- job = list_first_entry(&sched->ring_mirror_list,
+ job = list_first_entry_or_null(&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);
+ spin_lock_irqsave(&sched->job_list_lock, flags);
+
+ if (job && dma_fence_is_signaled(&job->s_fence->finished)) {
/* remove job from ring_mirror_list */
list_del_init(&job->node);
- spin_unlock_irqrestore(&sched->job_list_lock, flags);
-
- sched->ops->free_job(job);
+ } else {
+ job = NULL;
+ /* queue timeout for next job */
+ drm_sched_start_timeout(sched);
}
- /* 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);
+ return job;
}
/**
@@ -698,12 +696,18 @@ 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;
--
2.20.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v2] drm: Don't free jobs in wait_event_interruptible()
2019-09-26 9:54 [PATCH v2] drm: Don't free jobs in wait_event_interruptible() Steven Price
@ 2019-09-26 12:30 ` Steven Price
0 siblings, 0 replies; 2+ messages in thread
From: Steven Price @ 2019-09-26 12:30 UTC (permalink / raw)
To: Daniel Vetter, David Airlie, Christian König
Cc: Sharat Masetty, linux-kernel, dri-devel, Nayan Deshmukh, Alex Deucher
On 26/09/2019 10:54, Steven Price wrote:
> 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>
> ---
>
> Changes from v1:
> * Move list_first_entry_or_null() within the lock
Or rather that was my intention - but apparently I fat fingered and
didn't actually include this change. Sorry - v3 on it's way!
Steve
>
> drivers/gpu/drm/scheduler/sched_main.c | 44 ++++++++++++++------------
> 1 file changed, 24 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
> index 9a0ee74d82dc..0ed4aaa4e6d1 100644
> --- a/drivers/gpu/drm/scheduler/sched_main.c
> +++ b/drivers/gpu/drm/scheduler/sched_main.c
> @@ -622,43 +622,41 @@ 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)
> {
> + struct drm_sched_job *job = NULL;
> 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;
> -
> -
> - while (!list_empty(&sched->ring_mirror_list)) {
> - struct drm_sched_job *job;
> + return NULL;
>
> - job = list_first_entry(&sched->ring_mirror_list,
> + job = list_first_entry_or_null(&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);
> + spin_lock_irqsave(&sched->job_list_lock, flags);
> +
> + if (job && dma_fence_is_signaled(&job->s_fence->finished)) {
> /* remove job from ring_mirror_list */
> list_del_init(&job->node);
> - spin_unlock_irqrestore(&sched->job_list_lock, flags);
> -
> - sched->ops->free_job(job);
> + } else {
> + job = NULL;
> + /* queue timeout for next job */
> + drm_sched_start_timeout(sched);
> }
>
> - /* 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);
>
> + return job;
> }
>
> /**
> @@ -698,12 +696,18 @@ 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;
>
^ permalink raw reply [flat|nested] 2+ messages in thread
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