diff options
| author | Philipp Stanner <pstanner@redhat.com> | 2024-11-05 15:31:38 +0100 |
|---|---|---|
| committer | Philipp Stanner <pstanner@redhat.com> | 2024-11-07 10:05:54 +0100 |
| commit | baf4afc5831438b35de4b0e951b9cd58435a6d99 (patch) | |
| tree | a24612e36300c416e6afbad48fd23d5c6ac0b12d | |
| parent | 21c23e4b64e360d74d31b480f0572c2add0e8558 (diff) | |
drm/sched: Improve teardown documentationdrm-misc-next-2024-11-08
If jobs are still enqueued in struct drm_gpu_scheduler.pending_list
when drm_sched_fini() gets called, those jobs will be leaked since that
function stops both job-submission and (automatic) job-cleanup. It is,
thus, up to the driver to take care of preventing leaks.
The related function drm_sched_wqueue_stop() also prevents automatic job
cleanup.
Those pitfals are not reflected in the documentation, currently.
Explicitly inform about the leak problem in the docstring of
drm_sched_fini().
Additionally, detail the purpose of drm_sched_wqueue_{start,stop} and
hint at the consequences for automatic cleanup.
Signed-off-by: Philipp Stanner <pstanner@redhat.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241105143137.71893-2-pstanner@redhat.com
| -rw-r--r-- | drivers/gpu/drm/scheduler/sched_main.c | 23 |
1 files changed, 21 insertions, 2 deletions
diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c index eeaf71d43191..7ce25281c74c 100644 --- a/drivers/gpu/drm/scheduler/sched_main.c +++ b/drivers/gpu/drm/scheduler/sched_main.c @@ -1350,6 +1350,19 @@ EXPORT_SYMBOL(drm_sched_init); * @sched: scheduler instance * * Tears down and cleans up the scheduler. + * + * This stops submission of new jobs to the hardware through + * drm_sched_backend_ops.run_job(). Consequently, drm_sched_backend_ops.free_job() + * will not be called for all jobs still in drm_gpu_scheduler.pending_list. + * There is no solution for this currently. Thus, it is up to the driver to make + * sure that + * a) drm_sched_fini() is only called after for all submitted jobs + * drm_sched_backend_ops.free_job() has been called or that + * b) the jobs for which drm_sched_backend_ops.free_job() has not been called + * after drm_sched_fini() ran are freed manually. + * + * FIXME: Take care of the above problem and prevent this function from leaking + * the jobs in drm_gpu_scheduler.pending_list under any circumstances. */ void drm_sched_fini(struct drm_gpu_scheduler *sched) { @@ -1445,8 +1458,10 @@ EXPORT_SYMBOL(drm_sched_wqueue_ready); /** * drm_sched_wqueue_stop - stop scheduler submission - * * @sched: scheduler instance + * + * Stops the scheduler from pulling new jobs from entities. It also stops + * freeing jobs automatically through drm_sched_backend_ops.free_job(). */ void drm_sched_wqueue_stop(struct drm_gpu_scheduler *sched) { @@ -1458,8 +1473,12 @@ EXPORT_SYMBOL(drm_sched_wqueue_stop); /** * drm_sched_wqueue_start - start scheduler submission - * * @sched: scheduler instance + * + * Restarts the scheduler after drm_sched_wqueue_stop() has stopped it. + * + * This function is not necessary for 'conventional' startup. The scheduler is + * fully operational after drm_sched_init() succeeded. */ void drm_sched_wqueue_start(struct drm_gpu_scheduler *sched) { |