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drm/sched: Don't disturb the entity when in RR-mode scheduling

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Don't call drm_sched_select_entity() in drm_sched_run_job_queue().  In fact,
rename __drm_sched_run_job_queue() to just drm_sched_run_job_queue(), and let
it do just that, schedule the work item for execution.

The problem is that drm_sched_run_job_queue() calls drm_sched_select_entity()
to determine if the scheduler has an entity ready in one of its run-queues,
and in the case of the Round-Robin (RR) scheduling, the function
drm_sched_rq_select_entity_rr() does just that, selects the _next_ entity
which is ready, sets up the run-queue and completion and returns that
entity. The FIFO scheduling algorithm is unaffected.

Now, since drm_sched_run_job_work() also calls drm_sched_select_entity(), then
in the case of RR scheduling, that would result in drm_sched_select_entity()
having been called twice, which may result in skipping a ready entity if more
than one entity is ready. This commit fixes this by eliminating the call to
drm_sched_select_entity() from drm_sched_run_job_queue(), and leaves it only
in drm_sched_run_job_work().

v2: Rebased on top of Tvrtko's renames series of patches. (Luben)
    Add fixes-tag. (Tvrtko)

Signed-off-by: Luben Tuikov <ltuikov89@gmail.com>
Fixes: f7fe64ad0f ("drm/sched: Split free_job into own work item")
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Danilo Krummrich <dakr@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231107041020.10035-2-ltuikov89@gmail.com
This commit is contained in:
Luben Tuikov 2023-11-02 18:17:20 -04:00
parent c015fb6d01
commit bc8d6a9df9
1 changed files with 3 additions and 13 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

16
drivers/gpu/drm/scheduler/sched_main.c
View file

@ -256,10 +256,10 @@ drm_sched_rq_select_entity_fifo(struct drm_sched_rq *rq)
} }
/** /**
* __drm_sched_run_job_queue - enqueue run-job work * drm_sched_run_job_queue - enqueue run-job work
* @sched: scheduler instance * @sched: scheduler instance
*/ */
static void __drm_sched_run_job_queue(struct drm_gpu_scheduler *sched) static void drm_sched_run_job_queue(struct drm_gpu_scheduler *sched)
{ {
if (!READ_ONCE(sched->pause_submit)) if (!READ_ONCE(sched->pause_submit))
queue_work(sched->submit_wq, &sched->work_run_job); queue_work(sched->submit_wq, &sched->work_run_job);
@ -928,7 +928,7 @@ static bool drm_sched_can_queue(struct drm_gpu_scheduler *sched)
void drm_sched_wakeup(struct drm_gpu_scheduler *sched) void drm_sched_wakeup(struct drm_gpu_scheduler *sched)
{ {
if (drm_sched_can_queue(sched)) if (drm_sched_can_queue(sched))
__drm_sched_run_job_queue(sched); drm_sched_run_job_queue(sched);
} }
/** /**
@ -1040,16 +1040,6 @@ drm_sched_pick_best(struct drm_gpu_scheduler **sched_list,
} }
EXPORT_SYMBOL(drm_sched_pick_best); EXPORT_SYMBOL(drm_sched_pick_best);
/**
* drm_sched_run_job_queue - enqueue run-job work if there are ready entities
* @sched: scheduler instance
*/
static void drm_sched_run_job_queue(struct drm_gpu_scheduler *sched)
{
if (drm_sched_select_entity(sched))
__drm_sched_run_job_queue(sched);
}
/** /**
* drm_sched_free_job_work - worker to call free_job * drm_sched_free_job_work - worker to call free_job
* *