[PATCH v2 1/2] drm/sched: Add boolean to mark if sched is ready to work v2

Koenig, Christian Christian.Koenig at amd.com
Wed Oct 24 07:01:34 UTC 2018


Am 23.10.18 um 16:23 schrieb Grodzovsky, Andrey:
>
> On 10/22/2018 05:33 AM, Koenig, Christian wrote:
>> Am 19.10.18 um 22:52 schrieb Andrey Grodzovsky:
>>> Problem:
>>> A particular scheduler may become unsuable (underlying HW) after
>>> some event (e.g. GPU reset). If it's later chosen by
>>> the get free sched. policy a command will fail to be
>>> submitted.
>>>
>>> Fix:
>>> Add a driver specific callback to report the sched status so
>>> rq with bad sched can be avoided in favor of working one or
>>> none in which case job init will fail.
>>>
>>> v2: Switch from driver callback to flag in scheduler.
>>>
>>> Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky at amd.com>
>>> ---
>>>     drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c |  2 +-
>>>     drivers/gpu/drm/etnaviv/etnaviv_sched.c   |  2 +-
>>>     drivers/gpu/drm/scheduler/sched_entity.c  |  9 ++++++++-
>>>     drivers/gpu/drm/scheduler/sched_main.c    | 10 +++++++++-
>>>     drivers/gpu/drm/v3d/v3d_sched.c           |  4 ++--
>>>     include/drm/gpu_scheduler.h               |  5 ++++-
>>>     6 files changed, 25 insertions(+), 7 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
>>> index 5448cf2..bf845b0 100644
>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
>>> @@ -450,7 +450,7 @@ int amdgpu_fence_driver_init_ring(struct amdgpu_ring *ring,
>>>     
>>>     		r = drm_sched_init(&ring->sched, &amdgpu_sched_ops,
>>>     				   num_hw_submission, amdgpu_job_hang_limit,
>>> -				   timeout, ring->name);
>>> +				   timeout, ring->name, false);
>>>     		if (r) {
>>>     			DRM_ERROR("Failed to create scheduler on ring %s.\n",
>>>     				  ring->name);
>>> diff --git a/drivers/gpu/drm/etnaviv/etnaviv_sched.c b/drivers/gpu/drm/etnaviv/etnaviv_sched.c
>>> index f8c5f1e..9dca347 100644
>>> --- a/drivers/gpu/drm/etnaviv/etnaviv_sched.c
>>> +++ b/drivers/gpu/drm/etnaviv/etnaviv_sched.c
>>> @@ -178,7 +178,7 @@ int etnaviv_sched_init(struct etnaviv_gpu *gpu)
>>>     
>>>     	ret = drm_sched_init(&gpu->sched, &etnaviv_sched_ops,
>>>     			     etnaviv_hw_jobs_limit, etnaviv_job_hang_limit,
>>> -			     msecs_to_jiffies(500), dev_name(gpu->dev));
>>> +			     msecs_to_jiffies(500), dev_name(gpu->dev), true);
>>>     	if (ret)
>>>     		return ret;
>>>     
>>> diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c
>>> index 3e22a54..ba54c30 100644
>>> --- a/drivers/gpu/drm/scheduler/sched_entity.c
>>> +++ b/drivers/gpu/drm/scheduler/sched_entity.c
>>> @@ -130,7 +130,14 @@ drm_sched_entity_get_free_sched(struct drm_sched_entity *entity)
>>>     	int i;
>>>     
>>>     	for (i = 0; i < entity->num_rq_list; ++i) {
>>> -		num_jobs = atomic_read(&entity->rq_list[i]->sched->num_jobs);
>>> +		struct drm_gpu_scheduler *sched = entity->rq_list[i]->sched;
>>> +
>>> +		if (!entity->rq_list[i]->sched->ready) {
>>> +			DRM_WARN("sched%s is not ready, skipping", sched->name);
>>> +			continue;
>>> +		}
>>> +
>>> +		num_jobs = atomic_read(&sched->num_jobs);
>>>     		if (num_jobs < min_jobs) {
>>>     			min_jobs = num_jobs;
>>>     			rq = entity->rq_list[i];
>>> diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
>>> index 63b997d..772adec 100644
>>> --- a/drivers/gpu/drm/scheduler/sched_main.c
>>> +++ b/drivers/gpu/drm/scheduler/sched_main.c
>>> @@ -420,6 +420,9 @@ int drm_sched_job_init(struct drm_sched_job *job,
>>>     	struct drm_gpu_scheduler *sched;
>>>     
>>>     	drm_sched_entity_select_rq(entity);
>>> +	if (!entity->rq)
>>> +		return -ENOENT;
>>> +
>>>     	sched = entity->rq->sched;
>>>     
>>>     	job->sched = sched;
>>> @@ -598,6 +601,7 @@ static int drm_sched_main(void *param)
>>>      * @hang_limit: number of times to allow a job to hang before dropping it
>>>      * @timeout: timeout value in jiffies for the scheduler
>>>      * @name: name used for debugging
>>> + * @ready: marks if the underlying HW is ready to work
>>>      *
>>>      * Return 0 on success, otherwise error code.
>>>      */
>>> @@ -606,7 +610,8 @@ int drm_sched_init(struct drm_gpu_scheduler *sched,
>>>     		   unsigned hw_submission,
>>>     		   unsigned hang_limit,
>>>     		   long timeout,
>>> -		   const char *name)
>>> +		   const char *name,
>>> +		   bool	ready)
>> Please drop the ready flag here. We should consider a scheduler ready as
>> soon as it is initialized.
> Not totally agree with this because this flag marks that HW ready to run
> (the HW ring) and not the scheduler which is SW entity,

And exactly that's incorrect. This ready flag marks if the SW scheduler 
is ready to accept job submissions. If the underlying hardware is ready 
or not is completely irrelevant for this state.

For example we should NOT set it to false during GPU reset. Only when a 
reset failed and a HW engine runs into an unrecoverable failure then we 
can set the flag to false.

Saying this setting it to false in all the IP specific *_stop() and 
*_fini() functions is probably incorrect as well.

Christian.

> For amdgpu - drm_sched_init is called from the sw_init stage while the
> ring initialization and tests takes place in hw_init stage. Maybe if the
> flag is
> named 'hw_ready' instead of just 'ready' it would make more sense ?
> Also in case there is some code which today looks at 'ready' flag state
> to take some action and the code is executed after drm_sched_init but
> before
> amdgpu_ring_test_helper is called it will see the 'ready' flag == true
> instead of false as it's today.
>
> Andrey
>
>> Apart from that looks good to me,
>> Christian.
>>
>>>     {
>>>     	int i;
>>>     	sched->ops = ops;
>>> @@ -633,6 +638,7 @@ int drm_sched_init(struct drm_gpu_scheduler *sched,
>>>     		return PTR_ERR(sched->thread);
>>>     	}
>>>     
>>> +	sched->ready = ready;
>>>     	return 0;
>>>     }
>>>     EXPORT_SYMBOL(drm_sched_init);
>>> @@ -648,5 +654,7 @@ void drm_sched_fini(struct drm_gpu_scheduler *sched)
>>>     {
>>>     	if (sched->thread)
>>>     		kthread_stop(sched->thread);
>>> +
>>> +	sched->ready = false;
>>>     }
>>>     EXPORT_SYMBOL(drm_sched_fini);
>>> diff --git a/drivers/gpu/drm/v3d/v3d_sched.c b/drivers/gpu/drm/v3d/v3d_sched.c
>>> index 80b641f..7cedb5f 100644
>>> --- a/drivers/gpu/drm/v3d/v3d_sched.c
>>> +++ b/drivers/gpu/drm/v3d/v3d_sched.c
>>> @@ -212,7 +212,7 @@ v3d_sched_init(struct v3d_dev *v3d)
>>>     			     &v3d_sched_ops,
>>>     			     hw_jobs_limit, job_hang_limit,
>>>     			     msecs_to_jiffies(hang_limit_ms),
>>> -			     "v3d_bin");
>>> +			     "v3d_bin", true);
>>>     	if (ret) {
>>>     		dev_err(v3d->dev, "Failed to create bin scheduler: %d.", ret);
>>>     		return ret;
>>> @@ -222,7 +222,7 @@ v3d_sched_init(struct v3d_dev *v3d)
>>>     			     &v3d_sched_ops,
>>>     			     hw_jobs_limit, job_hang_limit,
>>>     			     msecs_to_jiffies(hang_limit_ms),
>>> -			     "v3d_render");
>>> +			     "v3d_render", true);
>>>     	if (ret) {
>>>     		dev_err(v3d->dev, "Failed to create render scheduler: %d.",
>>>     			ret);
>>> diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h
>>> index 0684dcd..037caea 100644
>>> --- a/include/drm/gpu_scheduler.h
>>> +++ b/include/drm/gpu_scheduler.h
>>> @@ -264,6 +264,7 @@ struct drm_sched_backend_ops {
>>>      * @hang_limit: once the hangs by a job crosses this limit then it is marked
>>>      *              guilty and it will be considered for scheduling further.
>>>      * @num_jobs: the number of jobs in queue in the scheduler
>>> + * @ready: marks if the underlying HW is ready to work
>>>      *
>>>      * One scheduler is implemented for each hardware ring.
>>>      */
>>> @@ -283,12 +284,14 @@ struct drm_gpu_scheduler {
>>>     	spinlock_t			job_list_lock;
>>>     	int				hang_limit;
>>>     	atomic_t                        num_jobs;
>>> +	bool			ready;
>>>     };
>>>     
>>>     int drm_sched_init(struct drm_gpu_scheduler *sched,
>>>     		   const struct drm_sched_backend_ops *ops,
>>>     		   uint32_t hw_submission, unsigned hang_limit, long timeout,
>>> -		   const char *name);
>>> +		   const char *name,
>>> +		   bool	ready);
>>>     void drm_sched_fini(struct drm_gpu_scheduler *sched);
>>>     int drm_sched_job_init(struct drm_sched_job *job,
>>>     		       struct drm_sched_entity *entity,
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