On 2022-09-30 07:51, Christian König wrote:
Am 29.09.22 um 21:20 schrieb Andrey Grodzovsky:On 2022-09-29 09:21, Christian König wrote:This was buggy because when we had to wait for entities which were killed as well we would just deadlock. Instead move all the dependency handling into the callbacks so that will all happen asynchronously. Signed-off-by: Christian König <christian.koenig@xxxxxxx> ---drivers/gpu/drm/scheduler/sched_entity.c | 197 +++++++++++------------1 file changed, 92 insertions(+), 105 deletions(-)diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.cindex 1bb1437a8fed..1d448e376811 100644 --- a/drivers/gpu/drm/scheduler/sched_entity.c +++ b/drivers/gpu/drm/scheduler/sched_entity.c@@ -139,6 +139,74 @@ bool drm_sched_entity_is_ready(struct drm_sched_entity *entity)return true; }+static void drm_sched_entity_kill_jobs_irq_work(struct irq_work *wrk)+{ + struct drm_sched_job *job = container_of(wrk, typeof(*job), work); + + drm_sched_fence_scheduled(job->s_fence); + drm_sched_fence_finished(job->s_fence); + WARN_ON(job->s_fence->parent); + job->sched->ops->free_job(job); +} ++/* Signal the scheduler finished fence when the entity in question is killed. */+static void drm_sched_entity_kill_jobs_cb(struct dma_fence *f, + struct dma_fence_cb *cb) +{ + struct drm_sched_job *job = container_of(cb, struct drm_sched_job, + finish_cb); + int r; + + dma_fence_put(f); + + /* Wait for all dependencies to avoid data corruptions */ + while (!xa_empty(&job->dependencies)) { + f = xa_erase(&job->dependencies, job->last_dependency++); + r = dma_fence_add_callback(f, &job->finish_cb, + drm_sched_entity_kill_jobs_cb); + if (!r) + return; + + dma_fence_put(f); + } + + init_irq_work(&job->work, drm_sched_entity_kill_jobs_irq_work); + irq_work_queue(&job->work); +} + +/* Remove the entity from the scheduler and kill all pending jobs */ +static void drm_sched_entity_kill(struct drm_sched_entity *entity) +{ + struct drm_sched_job *job; + struct dma_fence *prev; + + if (!entity->rq) + return; + + spin_lock(&entity->rq_lock); + entity->stopped = true; + drm_sched_rq_remove_entity(entity->rq, entity); + spin_unlock(&entity->rq_lock); ++ /* Make sure this entity is not used by the scheduler at the moment */+ wait_for_completion(&entity->entity_idle);Does it really stop processing in case more jobs are pending in entity queue already ? It probably makes sense to integrate drm_sched_entity_is_idle into drm_sched_entity_is_readyto prevent rq selecting this entity in such caseWe make sure that the entity is not used for scheduling any more by calling drm_sched_rq_remove_entity() right above this check here.The wait is only to prevent us from racing with the scheduler thread submitting one more job from the entity.
Ok, missed the entity remove in the code
+ + prev = dma_fence_get(entity->last_scheduled);+ while ((job = to_drm_sched_job(spsc_queue_pop(&entity->job_queue)))) {+ struct drm_sched_fence *s_fence = job->s_fence; + + dma_fence_set_error(&s_fence->finished, -ESRCH); + + dma_fence_get(&s_fence->finished); + if (!prev || dma_fence_add_callback(prev, &job->finish_cb, + drm_sched_entity_kill_jobs_cb)) + drm_sched_entity_kill_jobs_cb(NULL, &job->finish_cb); + + prev = &s_fence->finished; + } + dma_fence_put(prev); +} + /** * drm_sched_entity_flush - Flush a context entity *@@ -179,91 +247,13 @@ long drm_sched_entity_flush(struct drm_sched_entity *entity, long timeout)/* For killed process disable any more IBs enqueue right now */last_user = cmpxchg(&entity->last_user, current->group_leader, NULL);if ((!last_user || last_user == current->group_leader) &&- (current->flags & PF_EXITING) && (current->exit_code == SIGKILL)) {- spin_lock(&entity->rq_lock); - entity->stopped = true; - drm_sched_rq_remove_entity(entity->rq, entity); - spin_unlock(&entity->rq_lock); - }+ (current->flags & PF_EXITING) && (current->exit_code == SIGKILL))+ drm_sched_entity_kill(entity);This reverts 'drm/scheduler: only kill entity if last user is killed v2' and so might break this use case - when entitygets through FD into child process. Why this needs to be removed ?This patch isn't reverted. I keep the "last_user == current->group_leader" check in the line above.Christian.
OK, second time i didn't look carefully... My badAnother question - you call drm_sched_entity_kill now both in drm_sched_entity_flush and in drm_sched_entity_kill_jobs - so for drm_sched_entity_destroy it will be called twice, no ? because it will be called from drm_sched_entity_flush and from drm_sched_entity_fini. Why we need to call drm_sched_entity_kill from flush ? With your new async scheme of jobs killing we can even leave the flush code unchanged and just call drm_sched_entity_kill from drm_sched_entity_fini and no deadlock
will happen, what I am missing here ? Andrey
Andreyreturn ret; } EXPORT_SYMBOL(drm_sched_entity_flush);-static void drm_sched_entity_kill_jobs_irq_work(struct irq_work *wrk)-{ - struct drm_sched_job *job = container_of(wrk, typeof(*job), work); - - drm_sched_fence_finished(job->s_fence); - WARN_ON(job->s_fence->parent); - job->sched->ops->free_job(job); -} - --/* Signal the scheduler finished fence when the entity in question is killed. */-static void drm_sched_entity_kill_jobs_cb(struct dma_fence *f, - struct dma_fence_cb *cb) -{ - struct drm_sched_job *job = container_of(cb, struct drm_sched_job, - finish_cb); - - dma_fence_put(f); - init_irq_work(&job->work, drm_sched_entity_kill_jobs_irq_work); - irq_work_queue(&job->work); -} - -static struct dma_fence * -drm_sched_job_dependency(struct drm_sched_job *job, - struct drm_sched_entity *entity) -{ - if (!xa_empty(&job->dependencies)) - return xa_erase(&job->dependencies, job->last_dependency++); - - if (job->sched->ops->dependency) - return job->sched->ops->dependency(job, entity); - - return NULL; -} --static void drm_sched_entity_kill_jobs(struct drm_sched_entity *entity)-{ - struct drm_sched_job *job; - struct dma_fence *f; - int r; -- while ((job = to_drm_sched_job(spsc_queue_pop(&entity->job_queue)))) {- struct drm_sched_fence *s_fence = job->s_fence; - - /* Wait for all dependencies to avoid data corruptions */ - while ((f = drm_sched_job_dependency(job, entity))) { - dma_fence_wait(f, false); - dma_fence_put(f); - } - - drm_sched_fence_scheduled(s_fence); - dma_fence_set_error(&s_fence->finished, -ESRCH); - - /* - * When pipe is hanged by older entity, new entity might - * not even have chance to submit it's first job to HW - * and so entity->last_scheduled will remain NULL - */ - if (!entity->last_scheduled) { - drm_sched_entity_kill_jobs_cb(NULL, &job->finish_cb); - continue; - } - - dma_fence_get(entity->last_scheduled); - r = dma_fence_add_callback(entity->last_scheduled, - &job->finish_cb, - drm_sched_entity_kill_jobs_cb); - if (r == -ENOENT) - drm_sched_entity_kill_jobs_cb(NULL, &job->finish_cb); - else if (r) - DRM_ERROR("fence add callback failed (%d)\n", r); - } -} - /** * drm_sched_entity_fini - Destroy a context entity *@@ -277,33 +267,17 @@ static void drm_sched_entity_kill_jobs(struct drm_sched_entity *entity)*/ void drm_sched_entity_fini(struct drm_sched_entity *entity) { - struct drm_gpu_scheduler *sched = NULL; - - if (entity->rq) { - sched = entity->rq->sched; - drm_sched_rq_remove_entity(entity->rq, entity); - } - - /* Consumption of existing IBs wasn't completed. Forcefully - * remove them here. + /*+ * If consumption of existing IBs wasn't completed. Forcefully remove + * them here. Also makes sure that the scheduler won't touch this entity+ * any more. */ - if (spsc_queue_count(&entity->job_queue)) { - if (sched) { - /*- * Wait for thread to idle to make sure it isn't processing- * this entity. - */ - wait_for_completion(&entity->entity_idle); - - } - if (entity->dependency) { - dma_fence_remove_callback(entity->dependency, - &entity->cb); - dma_fence_put(entity->dependency); - entity->dependency = NULL; - } + drm_sched_entity_kill(entity); - drm_sched_entity_kill_jobs(entity); + if (entity->dependency) { + dma_fence_remove_callback(entity->dependency, &entity->cb); + dma_fence_put(entity->dependency); + entity->dependency = NULL; } dma_fence_put(entity->last_scheduled);@@ -415,6 +389,19 @@ static bool drm_sched_entity_add_dependency_cb(struct drm_sched_entity *entity)return false; } +static struct dma_fence * +drm_sched_job_dependency(struct drm_sched_job *job, + struct drm_sched_entity *entity) +{ + if (!xa_empty(&job->dependencies)) + return xa_erase(&job->dependencies, job->last_dependency++); + + if (job->sched->ops->dependency) + return job->sched->ops->dependency(job, entity); + + return NULL; +} +struct drm_sched_job *drm_sched_entity_pop_job(struct drm_sched_entity *entity){ struct drm_sched_job *sched_job;
