[RFC] Revert "drm/sched: Split free_job into own work item"
Mario Limonciello
mario.limonciello at amd.com
Tue Jan 23 17:46:27 UTC 2024
On 1/22/2024 20:11, Mario Limonciello wrote:
> commit f7fe64ad0f22 ("drm/sched: Split free_job into own work item")
> causes graphics hangs at GDM or right after logging in on a
> Framework 13 AMD laptop (containing a Phoenix APU).
>
> This reverts commit f7fe64ad0f22ff034f8ebcfbd7299ee9cc9b57d7.
>
> Fixes: f7fe64ad0f22 ("drm/sched: Split free_job into own work item")
> Signed-off-by: Mario Limonciello <mario.limonciello at amd.com>
> ---
> This is a regression introduced in 6.8-rc1, bisected from 6.7.
> This revert done on top of 6.8-rc1 fixes the issue.
>
> I'm happy to gather any data to use to properly debug if that is
> preferable to a revert.
BTW - nothing in kernel log when this happens.
I did catch an ftrace with all the GPU scheduler trace events though:
https://gist.github.com/superm1/1d3fc752a414f324fbde526052573acd
> ---
> drivers/gpu/drm/scheduler/sched_main.c | 133 +++++++++----------------
> include/drm/gpu_scheduler.h | 4 +-
> 2 files changed, 48 insertions(+), 89 deletions(-)
>
> diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
> index 550492a7a031..91c96ab53fb5 100644
> --- a/drivers/gpu/drm/scheduler/sched_main.c
> +++ b/drivers/gpu/drm/scheduler/sched_main.c
> @@ -369,32 +369,6 @@ static void drm_sched_run_job_queue(struct drm_gpu_scheduler *sched)
> queue_work(sched->submit_wq, &sched->work_run_job);
> }
>
> -/**
> - * __drm_sched_run_free_queue - enqueue free-job work
> - * @sched: scheduler instance
> - */
> -static void __drm_sched_run_free_queue(struct drm_gpu_scheduler *sched)
> -{
> - if (!READ_ONCE(sched->pause_submit))
> - queue_work(sched->submit_wq, &sched->work_free_job);
> -}
> -
> -/**
> - * drm_sched_run_free_queue - enqueue free-job work if ready
> - * @sched: scheduler instance
> - */
> -static void drm_sched_run_free_queue(struct drm_gpu_scheduler *sched)
> -{
> - struct drm_sched_job *job;
> -
> - spin_lock(&sched->job_list_lock);
> - job = list_first_entry_or_null(&sched->pending_list,
> - struct drm_sched_job, list);
> - if (job && dma_fence_is_signaled(&job->s_fence->finished))
> - __drm_sched_run_free_queue(sched);
> - spin_unlock(&sched->job_list_lock);
> -}
> -
> /**
> * drm_sched_job_done - complete a job
> * @s_job: pointer to the job which is done
> @@ -414,7 +388,7 @@ static void drm_sched_job_done(struct drm_sched_job *s_job, int result)
> dma_fence_get(&s_fence->finished);
> drm_sched_fence_finished(s_fence, result);
> dma_fence_put(&s_fence->finished);
> - __drm_sched_run_free_queue(sched);
> + drm_sched_run_job_queue(sched);
> }
>
> /**
> @@ -1092,10 +1066,8 @@ drm_sched_get_finished_job(struct drm_gpu_scheduler *sched)
> typeof(*next), list);
>
> if (next) {
> - if (test_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT,
> - &next->s_fence->scheduled.flags))
> - next->s_fence->scheduled.timestamp =
> - dma_fence_timestamp(&job->s_fence->finished);
> + next->s_fence->scheduled.timestamp =
> + dma_fence_timestamp(&job->s_fence->finished);
> /* start TO timer for next job */
> drm_sched_start_timeout(sched);
> }
> @@ -1145,29 +1117,7 @@ drm_sched_pick_best(struct drm_gpu_scheduler **sched_list,
> EXPORT_SYMBOL(drm_sched_pick_best);
>
> /**
> - * drm_sched_free_job_work - worker to call free_job
> - *
> - * @w: free job work
> - */
> -static void drm_sched_free_job_work(struct work_struct *w)
> -{
> - struct drm_gpu_scheduler *sched =
> - container_of(w, struct drm_gpu_scheduler, work_free_job);
> - struct drm_sched_job *job;
> -
> - if (READ_ONCE(sched->pause_submit))
> - return;
> -
> - job = drm_sched_get_finished_job(sched);
> - if (job)
> - sched->ops->free_job(job);
> -
> - drm_sched_run_free_queue(sched);
> - drm_sched_run_job_queue(sched);
> -}
> -
> -/**
> - * drm_sched_run_job_work - worker to call run_job
> + * drm_sched_run_job_work - main scheduler thread
> *
> * @w: run job work
> */
> @@ -1176,50 +1126,64 @@ static void drm_sched_run_job_work(struct work_struct *w)
> struct drm_gpu_scheduler *sched =
> container_of(w, struct drm_gpu_scheduler, work_run_job);
> struct drm_sched_entity *entity;
> - struct dma_fence *fence;
> - struct drm_sched_fence *s_fence;
> - struct drm_sched_job *sched_job;
> + struct drm_sched_job *cleanup_job;
> int r;
>
> if (READ_ONCE(sched->pause_submit))
> return;
>
> + cleanup_job = drm_sched_get_finished_job(sched);
> entity = drm_sched_select_entity(sched);
> - if (!entity)
> - return;
>
> - sched_job = drm_sched_entity_pop_job(entity);
> - if (!sched_job) {
> - complete_all(&entity->entity_idle);
> + if (!entity && !cleanup_job)
> return; /* No more work */
> - }
>
> - s_fence = sched_job->s_fence;
> + if (cleanup_job)
> + sched->ops->free_job(cleanup_job);
>
> - atomic_add(sched_job->credits, &sched->credit_count);
> - drm_sched_job_begin(sched_job);
> + if (entity) {
> + struct dma_fence *fence;
> + struct drm_sched_fence *s_fence;
> + struct drm_sched_job *sched_job;
> +
> + sched_job = drm_sched_entity_pop_job(entity);
> + if (!sched_job) {
> + complete_all(&entity->entity_idle);
> + if (!cleanup_job)
> + return; /* No more work */
> + goto again;
> + }
>
> - trace_drm_run_job(sched_job, entity);
> - fence = sched->ops->run_job(sched_job);
> - complete_all(&entity->entity_idle);
> - drm_sched_fence_scheduled(s_fence, fence);
> + s_fence = sched_job->s_fence;
>
> - if (!IS_ERR_OR_NULL(fence)) {
> - /* Drop for original kref_init of the fence */
> - dma_fence_put(fence);
> + atomic_inc(&sched->credit_count);
> + drm_sched_job_begin(sched_job);
>
> - r = dma_fence_add_callback(fence, &sched_job->cb,
> - drm_sched_job_done_cb);
> - if (r == -ENOENT)
> - drm_sched_job_done(sched_job, fence->error);
> - else if (r)
> - DRM_DEV_ERROR(sched->dev, "fence add callback failed (%d)\n", r);
> - } else {
> - drm_sched_job_done(sched_job, IS_ERR(fence) ?
> - PTR_ERR(fence) : 0);
> + trace_drm_run_job(sched_job, entity);
> + fence = sched->ops->run_job(sched_job);
> + complete_all(&entity->entity_idle);
> + drm_sched_fence_scheduled(s_fence, fence);
> +
> + if (!IS_ERR_OR_NULL(fence)) {
> + /* Drop for original kref_init of the fence */
> + dma_fence_put(fence);
> +
> + r = dma_fence_add_callback(fence, &sched_job->cb,
> + drm_sched_job_done_cb);
> + if (r == -ENOENT)
> + drm_sched_job_done(sched_job, fence->error);
> + else if (r)
> + DRM_DEV_ERROR(sched->dev, "fence add callback failed (%d)\n",
> + r);
> + } else {
> + drm_sched_job_done(sched_job, IS_ERR(fence) ?
> + PTR_ERR(fence) : 0);
> + }
> +
> + wake_up(&sched->job_scheduled);
> }
>
> - wake_up(&sched->job_scheduled);
> +again:
> drm_sched_run_job_queue(sched);
> }
>
> @@ -1304,7 +1268,6 @@ int drm_sched_init(struct drm_gpu_scheduler *sched,
> atomic_set(&sched->credit_count, 0);
> INIT_DELAYED_WORK(&sched->work_tdr, drm_sched_job_timedout);
> INIT_WORK(&sched->work_run_job, drm_sched_run_job_work);
> - INIT_WORK(&sched->work_free_job, drm_sched_free_job_work);
> atomic_set(&sched->_score, 0);
> atomic64_set(&sched->job_id_count, 0);
> sched->pause_submit = false;
> @@ -1432,7 +1395,6 @@ void drm_sched_wqueue_stop(struct drm_gpu_scheduler *sched)
> {
> WRITE_ONCE(sched->pause_submit, true);
> cancel_work_sync(&sched->work_run_job);
> - cancel_work_sync(&sched->work_free_job);
> }
> EXPORT_SYMBOL(drm_sched_wqueue_stop);
>
> @@ -1445,6 +1407,5 @@ void drm_sched_wqueue_start(struct drm_gpu_scheduler *sched)
> {
> WRITE_ONCE(sched->pause_submit, false);
> queue_work(sched->submit_wq, &sched->work_run_job);
> - queue_work(sched->submit_wq, &sched->work_free_job);
> }
> EXPORT_SYMBOL(drm_sched_wqueue_start);
> diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h
> index 5acc64954a88..72f64bd0a6eb 100644
> --- a/include/drm/gpu_scheduler.h
> +++ b/include/drm/gpu_scheduler.h
> @@ -495,10 +495,9 @@ struct drm_sched_backend_ops {
> * waits on this wait queue until all the scheduled jobs are
> * finished.
> * @job_id_count: used to assign unique id to the each job.
> - * @submit_wq: workqueue used to queue @work_run_job and @work_free_job
> + * @submit_wq: workqueue used to queue @work_run_job
> * @timeout_wq: workqueue used to queue @work_tdr
> * @work_run_job: work which calls run_job op of each scheduler.
> - * @work_free_job: work which calls free_job op of each scheduler.
> * @work_tdr: schedules a delayed call to @drm_sched_job_timedout after the
> * timeout interval is over.
> * @pending_list: the list of jobs which are currently in the job queue.
> @@ -528,7 +527,6 @@ struct drm_gpu_scheduler {
> struct workqueue_struct *submit_wq;
> struct workqueue_struct *timeout_wq;
> struct work_struct work_run_job;
> - struct work_struct work_free_job;
> struct delayed_work work_tdr;
> struct list_head pending_list;
> spinlock_t job_list_lock;
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