[PATCH v5 3/6] drm/scheduler: rework job destruction
Daniel Vetter
daniel at ffwll.ch
Wed May 29 10:02:47 UTC 2019
On Thu, Apr 18, 2019 at 5:00 PM Andrey Grodzovsky
<andrey.grodzovsky at amd.com> wrote:
>
> From: Christian König <christian.koenig at amd.com>
>
> We now destroy finished jobs from the worker thread to make sure that
> we never destroy a job currently in timeout processing.
> By this we avoid holding lock around ring mirror list in drm_sched_stop
> which should solve a deadlock reported by a user.
>
> v2: Remove unused variable.
> v4: Move guilty job free into sched code.
> v5:
> Move sched->hw_rq_count to drm_sched_start to account for counter
> decrement in drm_sched_stop even when we don't call resubmit jobs
> if guily job did signal.
>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=109692
>
> Signed-off-by: Christian König <christian.koenig at amd.com>
> Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky at amd.com>
$ make htmldocs
./drivers/gpu/drm/scheduler/sched_main.c:365: warning: Function
parameter or member 'bad' not described in 'drm_sched_stop'
Please fix, thanks.
-Daniel
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 9 +-
> drivers/gpu/drm/etnaviv/etnaviv_dump.c | 4 -
> drivers/gpu/drm/etnaviv/etnaviv_sched.c | 2 +-
> drivers/gpu/drm/lima/lima_sched.c | 2 +-
> drivers/gpu/drm/panfrost/panfrost_job.c | 2 +-
> drivers/gpu/drm/scheduler/sched_main.c | 159 +++++++++++++++++------------
> drivers/gpu/drm/v3d/v3d_sched.c | 2 +-
> include/drm/gpu_scheduler.h | 6 +-
> 8 files changed, 102 insertions(+), 84 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> index 7cee269..a0e165c 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> @@ -3334,7 +3334,7 @@ static int amdgpu_device_pre_asic_reset(struct amdgpu_device *adev,
> if (!ring || !ring->sched.thread)
> continue;
>
> - drm_sched_stop(&ring->sched);
> + drm_sched_stop(&ring->sched, &job->base);
>
> /* after all hw jobs are reset, hw fence is meaningless, so force_completion */
> amdgpu_fence_driver_force_completion(ring);
> @@ -3343,8 +3343,6 @@ static int amdgpu_device_pre_asic_reset(struct amdgpu_device *adev,
> if(job)
> drm_sched_increase_karma(&job->base);
>
> -
> -
> if (!amdgpu_sriov_vf(adev)) {
>
> if (!need_full_reset)
> @@ -3482,8 +3480,7 @@ static int amdgpu_do_asic_reset(struct amdgpu_hive_info *hive,
> return r;
> }
>
> -static void amdgpu_device_post_asic_reset(struct amdgpu_device *adev,
> - struct amdgpu_job *job)
> +static void amdgpu_device_post_asic_reset(struct amdgpu_device *adev)
> {
> int i;
>
> @@ -3623,7 +3620,7 @@ int amdgpu_device_gpu_recover(struct amdgpu_device *adev,
>
> /* Post ASIC reset for all devs .*/
> list_for_each_entry(tmp_adev, device_list_handle, gmc.xgmi.head) {
> - amdgpu_device_post_asic_reset(tmp_adev, tmp_adev == adev ? job : NULL);
> + amdgpu_device_post_asic_reset(tmp_adev);
>
> if (r) {
> /* bad news, how to tell it to userspace ? */
> diff --git a/drivers/gpu/drm/etnaviv/etnaviv_dump.c b/drivers/gpu/drm/etnaviv/etnaviv_dump.c
> index 33854c9..5778d9c 100644
> --- a/drivers/gpu/drm/etnaviv/etnaviv_dump.c
> +++ b/drivers/gpu/drm/etnaviv/etnaviv_dump.c
> @@ -135,13 +135,11 @@ void etnaviv_core_dump(struct etnaviv_gpu *gpu)
> mmu_size + gpu->buffer.size;
>
> /* Add in the active command buffers */
> - spin_lock_irqsave(&gpu->sched.job_list_lock, flags);
> list_for_each_entry(s_job, &gpu->sched.ring_mirror_list, node) {
> submit = to_etnaviv_submit(s_job);
> file_size += submit->cmdbuf.size;
> n_obj++;
> }
> - spin_unlock_irqrestore(&gpu->sched.job_list_lock, flags);
>
> /* Add in the active buffer objects */
> list_for_each_entry(vram, &gpu->mmu->mappings, mmu_node) {
> @@ -183,14 +181,12 @@ void etnaviv_core_dump(struct etnaviv_gpu *gpu)
> gpu->buffer.size,
> etnaviv_cmdbuf_get_va(&gpu->buffer));
>
> - spin_lock_irqsave(&gpu->sched.job_list_lock, flags);
> list_for_each_entry(s_job, &gpu->sched.ring_mirror_list, node) {
> submit = to_etnaviv_submit(s_job);
> etnaviv_core_dump_mem(&iter, ETDUMP_BUF_CMD,
> submit->cmdbuf.vaddr, submit->cmdbuf.size,
> etnaviv_cmdbuf_get_va(&submit->cmdbuf));
> }
> - spin_unlock_irqrestore(&gpu->sched.job_list_lock, flags);
>
> /* Reserve space for the bomap */
> if (n_bomap_pages) {
> diff --git a/drivers/gpu/drm/etnaviv/etnaviv_sched.c b/drivers/gpu/drm/etnaviv/etnaviv_sched.c
> index 6d24fea..a813c82 100644
> --- a/drivers/gpu/drm/etnaviv/etnaviv_sched.c
> +++ b/drivers/gpu/drm/etnaviv/etnaviv_sched.c
> @@ -109,7 +109,7 @@ static void etnaviv_sched_timedout_job(struct drm_sched_job *sched_job)
> }
>
> /* block scheduler */
> - drm_sched_stop(&gpu->sched);
> + drm_sched_stop(&gpu->sched, sched_job);
>
> if(sched_job)
> drm_sched_increase_karma(sched_job);
> diff --git a/drivers/gpu/drm/lima/lima_sched.c b/drivers/gpu/drm/lima/lima_sched.c
> index 97bd9c1..df98931 100644
> --- a/drivers/gpu/drm/lima/lima_sched.c
> +++ b/drivers/gpu/drm/lima/lima_sched.c
> @@ -300,7 +300,7 @@ static struct dma_fence *lima_sched_run_job(struct drm_sched_job *job)
> static void lima_sched_handle_error_task(struct lima_sched_pipe *pipe,
> struct lima_sched_task *task)
> {
> - drm_sched_stop(&pipe->base);
> + drm_sched_stop(&pipe->base, &task->base);
>
> if (task)
> drm_sched_increase_karma(&task->base);
> diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c
> index 0a7ed04..c6336b7 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_job.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_job.c
> @@ -385,7 +385,7 @@ static void panfrost_job_timedout(struct drm_sched_job *sched_job)
> sched_job);
>
> for (i = 0; i < NUM_JOB_SLOTS; i++)
> - drm_sched_stop(&pfdev->js->queue[i].sched);
> + drm_sched_stop(&pfdev->js->queue[i].sched, sched_job);
>
> if (sched_job)
> drm_sched_increase_karma(sched_job);
> diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
> index 19fc601..7816de7 100644
> --- a/drivers/gpu/drm/scheduler/sched_main.c
> +++ b/drivers/gpu/drm/scheduler/sched_main.c
> @@ -265,32 +265,6 @@ void drm_sched_resume_timeout(struct drm_gpu_scheduler *sched,
> }
> EXPORT_SYMBOL(drm_sched_resume_timeout);
>
> -/* job_finish is called after hw fence signaled
> - */
> -static void drm_sched_job_finish(struct work_struct *work)
> -{
> - struct drm_sched_job *s_job = container_of(work, struct drm_sched_job,
> - finish_work);
> - struct drm_gpu_scheduler *sched = s_job->sched;
> - unsigned long flags;
> -
> - /*
> - * Canceling the timeout without removing our job from the ring mirror
> - * list is safe, as we will only end up in this worker if our jobs
> - * finished fence has been signaled. So even if some another worker
> - * manages to find this job as the next job in the list, the fence
> - * signaled check below will prevent the timeout to be restarted.
> - */
> - cancel_delayed_work_sync(&sched->work_tdr);
> -
> - spin_lock_irqsave(&sched->job_list_lock, flags);
> - /* queue TDR for next job */
> - drm_sched_start_timeout(sched);
> - spin_unlock_irqrestore(&sched->job_list_lock, flags);
> -
> - sched->ops->free_job(s_job);
> -}
> -
> static void drm_sched_job_begin(struct drm_sched_job *s_job)
> {
> struct drm_gpu_scheduler *sched = s_job->sched;
> @@ -315,6 +289,13 @@ static void drm_sched_job_timedout(struct work_struct *work)
> if (job)
> job->sched->ops->timedout_job(job);
>
> + /*
> + * Guilty job did complete and hence needs to be manually removed
> + * See drm_sched_stop doc.
> + */
> + if (list_empty(&job->node))
> + job->sched->ops->free_job(job);
> +
> spin_lock_irqsave(&sched->job_list_lock, flags);
> drm_sched_start_timeout(sched);
> spin_unlock_irqrestore(&sched->job_list_lock, flags);
> @@ -371,23 +352,26 @@ EXPORT_SYMBOL(drm_sched_increase_karma);
> * @sched: scheduler instance
> * @bad: bad scheduler job
> *
> + * Stop the scheduler and also removes and frees all completed jobs.
> + * Note: bad job will not be freed as it might be used later and so it's
> + * callers responsibility to release it manually if it's not part of the
> + * mirror list any more.
> + *
> */
> -void drm_sched_stop(struct drm_gpu_scheduler *sched)
> +void drm_sched_stop(struct drm_gpu_scheduler *sched, struct drm_sched_job *bad)
> {
> - struct drm_sched_job *s_job;
> + struct drm_sched_job *s_job, *tmp;
> unsigned long flags;
> - struct dma_fence *last_fence = NULL;
>
> kthread_park(sched->thread);
>
> /*
> - * Verify all the signaled jobs in mirror list are removed from the ring
> - * by waiting for the latest job to enter the list. This should insure that
> - * also all the previous jobs that were in flight also already singaled
> - * and removed from the list.
> + * Iterate the job list from later to earlier one and either deactive
> + * their HW callbacks or remove them from mirror list if they already
> + * signaled.
> + * This iteration is thread safe as sched thread is stopped.
> */
> - spin_lock_irqsave(&sched->job_list_lock, flags);
> - list_for_each_entry_reverse(s_job, &sched->ring_mirror_list, node) {
> + list_for_each_entry_safe_reverse(s_job, tmp, &sched->ring_mirror_list, node) {
> if (s_job->s_fence->parent &&
> dma_fence_remove_callback(s_job->s_fence->parent,
> &s_job->cb)) {
> @@ -395,16 +379,30 @@ void drm_sched_stop(struct drm_gpu_scheduler *sched)
> s_job->s_fence->parent = NULL;
> atomic_dec(&sched->hw_rq_count);
> } else {
> - last_fence = dma_fence_get(&s_job->s_fence->finished);
> - break;
> + /*
> + * remove job from ring_mirror_list.
> + * Locking here is for concurrent resume timeout
> + */
> + spin_lock_irqsave(&sched->job_list_lock, flags);
> + list_del_init(&s_job->node);
> + spin_unlock_irqrestore(&sched->job_list_lock, flags);
> +
> + /*
> + * Wait for job's HW fence callback to finish using s_job
> + * before releasing it.
> + *
> + * Job is still alive so fence refcount at least 1
> + */
> + dma_fence_wait(&s_job->s_fence->finished, false);
> +
> + /*
> + * We must keep bad job alive for later use during
> + * recovery by some of the drivers
> + */
> + if (bad != s_job)
> + sched->ops->free_job(s_job);
> }
> }
> - spin_unlock_irqrestore(&sched->job_list_lock, flags);
> -
> - if (last_fence) {
> - dma_fence_wait(last_fence, false);
> - dma_fence_put(last_fence);
> - }
> }
>
> EXPORT_SYMBOL(drm_sched_stop);
> @@ -418,21 +416,22 @@ EXPORT_SYMBOL(drm_sched_stop);
> void drm_sched_start(struct drm_gpu_scheduler *sched, bool full_recovery)
> {
> struct drm_sched_job *s_job, *tmp;
> + unsigned long flags;
> int r;
>
> - if (!full_recovery)
> - goto unpark;
> -
> /*
> * Locking the list is not required here as the sched thread is parked
> - * so no new jobs are being pushed in to HW and in drm_sched_stop we
> - * flushed all the jobs who were still in mirror list but who already
> - * signaled and removed them self from the list. Also concurrent
> + * so no new jobs are being inserted or removed. Also concurrent
> * GPU recovers can't run in parallel.
> */
> list_for_each_entry_safe(s_job, tmp, &sched->ring_mirror_list, node) {
> struct dma_fence *fence = s_job->s_fence->parent;
>
> + atomic_inc(&sched->hw_rq_count);
> +
> + if (!full_recovery)
> + continue;
> +
> if (fence) {
> r = dma_fence_add_callback(fence, &s_job->cb,
> drm_sched_process_job);
> @@ -445,9 +444,12 @@ void drm_sched_start(struct drm_gpu_scheduler *sched, bool full_recovery)
> drm_sched_process_job(NULL, &s_job->cb);
> }
>
> - drm_sched_start_timeout(sched);
> + if (full_recovery) {
> + spin_lock_irqsave(&sched->job_list_lock, flags);
> + drm_sched_start_timeout(sched);
> + spin_unlock_irqrestore(&sched->job_list_lock, flags);
> + }
>
> -unpark:
> kthread_unpark(sched->thread);
> }
> EXPORT_SYMBOL(drm_sched_start);
> @@ -464,7 +466,6 @@ void drm_sched_resubmit_jobs(struct drm_gpu_scheduler *sched)
> uint64_t guilty_context;
> bool found_guilty = false;
>
> - /*TODO DO we need spinlock here ? */
> list_for_each_entry_safe(s_job, tmp, &sched->ring_mirror_list, node) {
> struct drm_sched_fence *s_fence = s_job->s_fence;
>
> @@ -477,7 +478,6 @@ void drm_sched_resubmit_jobs(struct drm_gpu_scheduler *sched)
> dma_fence_set_error(&s_fence->finished, -ECANCELED);
>
> s_job->s_fence->parent = sched->ops->run_job(s_job);
> - atomic_inc(&sched->hw_rq_count);
> }
> }
> EXPORT_SYMBOL(drm_sched_resubmit_jobs);
> @@ -514,7 +514,6 @@ int drm_sched_job_init(struct drm_sched_job *job,
> return -ENOMEM;
> job->id = atomic64_inc_return(&sched->job_id_count);
>
> - INIT_WORK(&job->finish_work, drm_sched_job_finish);
> INIT_LIST_HEAD(&job->node);
>
> return 0;
> @@ -597,24 +596,53 @@ static void drm_sched_process_job(struct dma_fence *f, struct dma_fence_cb *cb)
> struct drm_sched_job *s_job = container_of(cb, struct drm_sched_job, cb);
> struct drm_sched_fence *s_fence = s_job->s_fence;
> struct drm_gpu_scheduler *sched = s_fence->sched;
> - unsigned long flags;
> -
> - cancel_delayed_work(&sched->work_tdr);
>
> atomic_dec(&sched->hw_rq_count);
> atomic_dec(&sched->num_jobs);
>
> - spin_lock_irqsave(&sched->job_list_lock, flags);
> - /* remove job from ring_mirror_list */
> - list_del_init(&s_job->node);
> - spin_unlock_irqrestore(&sched->job_list_lock, flags);
> + trace_drm_sched_process_job(s_fence);
>
> drm_sched_fence_finished(s_fence);
> -
> - trace_drm_sched_process_job(s_fence);
> wake_up_interruptible(&sched->wake_up_worker);
> +}
> +
> +/**
> + * drm_sched_cleanup_jobs - destroy finished jobs
> + *
> + * @sched: scheduler instance
> + *
> + * Remove all finished jobs from the mirror list and destroy them.
> + */
> +static void drm_sched_cleanup_jobs(struct drm_gpu_scheduler *sched)
> +{
> + unsigned long flags;
> +
> + /* Don't destroy jobs while the timeout worker is running */
> + if (!cancel_delayed_work(&sched->work_tdr))
> + return;
> +
> +
> + while (!list_empty(&sched->ring_mirror_list)) {
> + struct drm_sched_job *job;
> +
> + job = list_first_entry(&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);
> + /* remove job from ring_mirror_list */
> + list_del_init(&job->node);
> + spin_unlock_irqrestore(&sched->job_list_lock, flags);
> +
> + sched->ops->free_job(job);
> + }
> +
> + /* 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);
>
> - schedule_work(&s_job->finish_work);
> }
>
> /**
> @@ -656,9 +684,10 @@ static int drm_sched_main(void *param)
> struct dma_fence *fence;
>
> wait_event_interruptible(sched->wake_up_worker,
> + (drm_sched_cleanup_jobs(sched),
> (!drm_sched_blocked(sched) &&
> (entity = drm_sched_select_entity(sched))) ||
> - kthread_should_stop());
> + kthread_should_stop()));
>
> if (!entity)
> continue;
> diff --git a/drivers/gpu/drm/v3d/v3d_sched.c b/drivers/gpu/drm/v3d/v3d_sched.c
> index e740f3b..1a4abe7 100644
> --- a/drivers/gpu/drm/v3d/v3d_sched.c
> +++ b/drivers/gpu/drm/v3d/v3d_sched.c
> @@ -232,7 +232,7 @@ v3d_gpu_reset_for_timeout(struct v3d_dev *v3d, struct drm_sched_job *sched_job)
>
> /* block scheduler */
> for (q = 0; q < V3D_MAX_QUEUES; q++)
> - drm_sched_stop(&v3d->queue[q].sched);
> + drm_sched_stop(&v3d->queue[q].sched, sched_job);
>
> if (sched_job)
> drm_sched_increase_karma(sched_job);
> diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h
> index 0daca4d..9ee0f27 100644
> --- a/include/drm/gpu_scheduler.h
> +++ b/include/drm/gpu_scheduler.h
> @@ -167,9 +167,6 @@ struct drm_sched_fence *to_drm_sched_fence(struct dma_fence *f);
> * @sched: the scheduler instance on which this job is scheduled.
> * @s_fence: contains the fences for the scheduling of job.
> * @finish_cb: the callback for the finished fence.
> - * @finish_work: schedules the function @drm_sched_job_finish once the job has
> - * finished to remove the job from the
> - * @drm_gpu_scheduler.ring_mirror_list.
> * @node: used to append this struct to the @drm_gpu_scheduler.ring_mirror_list.
> * @id: a unique id assigned to each job scheduled on the scheduler.
> * @karma: increment on every hang caused by this job. If this exceeds the hang
> @@ -188,7 +185,6 @@ struct drm_sched_job {
> struct drm_gpu_scheduler *sched;
> struct drm_sched_fence *s_fence;
> struct dma_fence_cb finish_cb;
> - struct work_struct finish_work;
> struct list_head node;
> uint64_t id;
> atomic_t karma;
> @@ -296,7 +292,7 @@ int drm_sched_job_init(struct drm_sched_job *job,
> void *owner);
> void drm_sched_job_cleanup(struct drm_sched_job *job);
> void drm_sched_wakeup(struct drm_gpu_scheduler *sched);
> -void drm_sched_stop(struct drm_gpu_scheduler *sched);
> +void drm_sched_stop(struct drm_gpu_scheduler *sched, struct drm_sched_job *bad);
> void drm_sched_start(struct drm_gpu_scheduler *sched, bool full_recovery);
> void drm_sched_resubmit_jobs(struct drm_gpu_scheduler *sched);
> void drm_sched_increase_karma(struct drm_sched_job *bad);
> --
> 2.7.4
>
> _______________________________________________
> dri-devel mailing list
> dri-devel at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
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