Re: [Intel-gfx] [PATCH v5 01/20] drm/sched: Split drm_sched_job_init

Christian König
2021-08-05T13:44:06Z

Am 05.08.21 um 12:46 schrieb Daniel Vetter:
> This is a very confusingly named function, because not just does it
> init an object, it arms it and provides a point of no return for
> pushing a job into the scheduler. It would be nice if that's a bit
> clearer in the interface.
>
> But the real reason is that I want to push the dependency tracking
> helpers into the scheduler code, and that means drm_sched_job_init
> must be called a lot earlier, without arming the job.
>
> v2:
> - don't change .gitignore (Steven)
> - don't forget v3d (Emma)
>
> v3: Emma noticed that I leak the memory allocated in
> drm_sched_job_init if we bail out before the point of no return in
> subsequent driver patches. To be able to fix this change
> drm_sched_job_cleanup() so it can handle being called both before and
> after drm_sched_job_arm().
>
> Also improve the kerneldoc for this.
>
> v4:
> - Fix the drm_sched_job_cleanup logic, I inverted the booleans, as
> usual (Melissa)
>
> - Christian pointed out that drm_sched_entity_select_rq() also needs
> to be moved into drm_sched_job_arm, which made me realize that the
> job->id definitely needs to be moved too.
>
> Shuffle things to fit between job_init and job_arm.
>
> v5:
> Reshuffle the split between init/arm once more, amdgpu abuses
> drm_sched.ready to signal gpu reset failures. Also document this
> somewhat. (Christian)
>
> v6:
> Rebase on top of the msm drm/sched support. Note that the
> drm_sched_job_init() call is completely misplaced, and hence also the
> split-out drm_sched_entity_push_job(). I've put in a FIXME which the next
> patch will address.
>
> Acked-by: Melissa Wen <mwen@igalia.com>
> Cc: Melissa Wen <melissa.srw@gmail.com>
> Acked-by: Emma Anholt <emma@anholt.net>
> Acked-by: Steven Price <steven.price@arm.com> (v2)
> Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com> (v5)
> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

At least the amdgpu parts look ok of hand, but I can't judge the rest I
think.

So only Acked-by: Christian König <christian.koenig@amd.com>

> Cc: Lucas Stach <l.stach@pengutronix.de>
> Cc: Russell King <linux+etnaviv@armlinux.org.uk>
> Cc: Christian Gmeiner <christian.gmeiner@gmail.com>
> Cc: Qiang Yu <yuq825@gmail.com>
> Cc: Rob Herring <robh@kernel.org>
> Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
> Cc: Steven Price <steven.price@arm.com>
> Cc: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
> Cc: David Airlie <airlied@linux.ie>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> Cc: Sumit Semwal <sumit.semwal@linaro.org>
> Cc: "Christian König" <christian.koenig@amd.com>
> Cc: Masahiro Yamada <masahiroy@kernel.org>
> Cc: Kees Cook <keescook@chromium.org>
> Cc: Adam Borowski <kilobyte@angband.pl>
> Cc: Nick Terrell <terrelln@fb.com>
> Cc: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
> Cc: Paul Menzel <pmenzel@molgen.mpg.de>
> Cc: Sami Tolvanen <samitolvanen@google.com>
> Cc: Viresh Kumar <viresh.kumar@linaro.org>
> Cc: Alex Deucher <alexander.deucher@amd.com>
> Cc: Dave Airlie <airlied@redhat.com>
> Cc: Nirmoy Das <nirmoy.das@amd.com>
> Cc: Deepak R Varma <mh12gx2825@gmail.com>
> Cc: Lee Jones <lee.jones@linaro.org>
> Cc: Kevin Wang <kevin1.wang@amd.com>
> Cc: Chen Li <chenli@uniontech.com>
> Cc: Luben Tuikov <luben.tuikov@amd.com>
> Cc: "Marek Olšák" <marek.olsak@amd.com>
> Cc: Dennis Li <Dennis.Li@amd.com>
> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Cc: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
> Cc: Sonny Jiang <sonny.jiang@amd.com>
> Cc: Boris Brezillon <boris.brezillon@collabora.com>
> Cc: Tian Tao <tiantao6@hisilicon.com>
> Cc: etnaviv@lists.freedesktop.org
> Cc: lima@lists.freedesktop.org
> Cc: linux-media@vger.kernel.org
> Cc: linaro-mm-sig@lists.linaro.org
> Cc: Emma Anholt <emma@anholt.net>
> Cc: Rob Clark <robdclark@gmail.com>
> Cc: Sean Paul <sean@poorly.run>
> Cc: linux-arm-msm@vger.kernel.org
> Cc: freedreno@lists.freedesktop.org
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 2 +
> drivers/gpu/drm/amd/amdgpu/amdgpu_job.c | 2 +
> drivers/gpu/drm/etnaviv/etnaviv_sched.c | 2 +
> drivers/gpu/drm/lima/lima_sched.c | 2 +
> drivers/gpu/drm/msm/msm_gem_submit.c | 3 ++
> drivers/gpu/drm/panfrost/panfrost_job.c | 2 +
> drivers/gpu/drm/scheduler/sched_entity.c | 6 +--
> drivers/gpu/drm/scheduler/sched_fence.c | 19 ++++---
> drivers/gpu/drm/scheduler/sched_main.c | 69 ++++++++++++++++++++----
> drivers/gpu/drm/v3d/v3d_gem.c | 2 +
> include/drm/gpu_scheduler.h | 7 ++-
> 11 files changed, 94 insertions(+), 22 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> index 139cd3bf1ad6..32e80bc6af22 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> @@ -1226,6 +1226,8 @@ static int amdgpu_cs_submit(struct amdgpu_cs_parser *p,
> if (r)
> goto error_unlock;
>
> + drm_sched_job_arm(&job->base);
> +
> /* No memory allocation is allowed while holding the notifier lock.
> * The lock is held until amdgpu_cs_submit is finished and fence is
> * added to BOs.
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
> index d33e6d97cc89..5ddb955d2315 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
> @@ -170,6 +170,8 @@ int amdgpu_job_submit(struct amdgpu_job *job, struct drm_sched_entity *entity,
> if (r)
> return r;
>
> + drm_sched_job_arm(&job->base);
> +
> *f = dma_fence_get(&job->base.s_fence->finished);
> amdgpu_job_free_resources(job);
> drm_sched_entity_push_job(&job->base, entity);
> diff --git a/drivers/gpu/drm/etnaviv/etnaviv_sched.c b/drivers/gpu/drm/etnaviv/etnaviv_sched.c
> index feb6da1b6ceb..05f412204118 100644
> --- a/drivers/gpu/drm/etnaviv/etnaviv_sched.c
> +++ b/drivers/gpu/drm/etnaviv/etnaviv_sched.c
> @@ -163,6 +163,8 @@ int etnaviv_sched_push_job(struct drm_sched_entity *sched_entity,
> if (ret)
> goto out_unlock;
>
> + drm_sched_job_arm(&submit->sched_job);
> +
> submit->out_fence = dma_fence_get(&submit->sched_job.s_fence->finished);
> submit->out_fence_id = idr_alloc_cyclic(&submit->gpu->fence_idr,
> submit->out_fence, 0,
> diff --git a/drivers/gpu/drm/lima/lima_sched.c b/drivers/gpu/drm/lima/lima_sched.c
> index dba8329937a3..38f755580507 100644
> --- a/drivers/gpu/drm/lima/lima_sched.c
> +++ b/drivers/gpu/drm/lima/lima_sched.c
> @@ -129,6 +129,8 @@ int lima_sched_task_init(struct lima_sched_task *task,
> return err;
> }
>
> + drm_sched_job_arm(&task->base);
> +
> task->num_bos = num_bos;
> task->vm = lima_vm_get(vm);
>
> diff --git a/drivers/gpu/drm/msm/msm_gem_submit.c b/drivers/gpu/drm/msm/msm_gem_submit.c
> index fdc5367aecaa..6d6c44f0e1f3 100644
> --- a/drivers/gpu/drm/msm/msm_gem_submit.c
> +++ b/drivers/gpu/drm/msm/msm_gem_submit.c
> @@ -52,6 +52,9 @@ static struct msm_gem_submit *submit_create(struct drm_device *dev,
> return ERR_PTR(ret);
> }
>
> + /* FIXME: this is way too early */
> + drm_sched_job_arm(&job->base);
> +
> xa_init_flags(&submit->deps, XA_FLAGS_ALLOC);
>
> kref_init(&submit->ref);
> diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c
> index 71a72fb50e6b..2992dc85325f 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_job.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_job.c
> @@ -288,6 +288,8 @@ int panfrost_job_push(struct panfrost_job *job)
> goto unlock;
> }
>
> + drm_sched_job_arm(&job->base);
> +
> job->render_done_fence = dma_fence_get(&job->base.s_fence->finished);
>
> ret = panfrost_acquire_object_fences(job->bos, job->bo_count,
> diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c
> index 79554aa4dbb1..f7347c284886 100644
> --- a/drivers/gpu/drm/scheduler/sched_entity.c
> +++ b/drivers/gpu/drm/scheduler/sched_entity.c
> @@ -485,9 +485,9 @@ void drm_sched_entity_select_rq(struct drm_sched_entity *entity)
> * @sched_job: job to submit
> * @entity: scheduler entity
> *
> - * Note: To guarantee that the order of insertion to queue matches
> - * the job's fence sequence number this function should be
> - * called with drm_sched_job_init under common lock.
> + * Note: To guarantee that the order of insertion to queue matches the job's
> + * fence sequence number this function should be called with drm_sched_job_arm()
> + * under common lock.
> *
> * Returns 0 for success, negative error code otherwise.
> */
> diff --git a/drivers/gpu/drm/scheduler/sched_fence.c b/drivers/gpu/drm/scheduler/sched_fence.c
> index 69de2c76731f..bcea035cf4c6 100644
> --- a/drivers/gpu/drm/scheduler/sched_fence.c
> +++ b/drivers/gpu/drm/scheduler/sched_fence.c
> @@ -90,7 +90,7 @@ static const char *drm_sched_fence_get_timeline_name(struct dma_fence *f)
> *
> * Free up the fence memory after the RCU grace period.
> */
> -static void drm_sched_fence_free(struct rcu_head *rcu)
> +void drm_sched_fence_free(struct rcu_head *rcu)
> {
> struct dma_fence *f = container_of(rcu, struct dma_fence, rcu);
> struct drm_sched_fence *fence = to_drm_sched_fence(f);
> @@ -152,27 +152,32 @@ struct drm_sched_fence *to_drm_sched_fence(struct dma_fence *f)
> }
> EXPORT_SYMBOL(to_drm_sched_fence);
>
> -struct drm_sched_fence *drm_sched_fence_create(struct drm_sched_entity *entity,
> - void *owner)
> +struct drm_sched_fence *drm_sched_fence_alloc(struct drm_sched_entity *entity,
> + void *owner)
> {
> struct drm_sched_fence *fence = NULL;
> - unsigned seq;
>
> fence = kmem_cache_zalloc(sched_fence_slab, GFP_KERNEL);
> if (fence == NULL)
> return NULL;
>
> fence->owner = owner;
> - fence->sched = entity->rq->sched;
> spin_lock_init(&fence->lock);
>
> + return fence;
> +}
> +
> +void drm_sched_fence_init(struct drm_sched_fence *fence,
> + struct drm_sched_entity *entity)
> +{
> + unsigned seq;
> +
> + fence->sched = entity->rq->sched;
> seq = atomic_inc_return(&entity->fence_seq);
> dma_fence_init(&fence->scheduled, &drm_sched_fence_ops_scheduled,
> &fence->lock, entity->fence_context, seq);
> dma_fence_init(&fence->finished, &drm_sched_fence_ops_finished,
> &fence->lock, entity->fence_context + 1, seq);
> -
> - return fence;
> }
>
> module_init(drm_sched_fence_slab_init);
> diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
> index 33c414d55fab..454cb6164bdc 100644
> --- a/drivers/gpu/drm/scheduler/sched_main.c
> +++ b/drivers/gpu/drm/scheduler/sched_main.c
> @@ -48,9 +48,11 @@
> #include <linux/wait.h>
> #include <linux/sched.h>
> #include <linux/completion.h>
> +#include <linux/dma-resv.h>
> #include <uapi/linux/sched/types.h>
>
> #include <drm/drm_print.h>
> +#include <drm/drm_gem.h>
> #include <drm/gpu_scheduler.h>
> #include <drm/spsc_queue.h>
>
> @@ -569,7 +571,6 @@ EXPORT_SYMBOL(drm_sched_resubmit_jobs_ext);
>
> /**
> * drm_sched_job_init - init a scheduler job
> - *
> * @job: scheduler job to init
> * @entity: scheduler entity to use
> * @owner: job owner for debugging
> @@ -577,27 +578,28 @@ EXPORT_SYMBOL(drm_sched_resubmit_jobs_ext);
> * Refer to drm_sched_entity_push_job() documentation
> * for locking considerations.
> *
> + * Drivers must make sure drm_sched_job_cleanup() if this function returns
> + * successfully, even when @job is aborted before drm_sched_job_arm() is called.
> + *
> + * WARNING: amdgpu abuses &drm_sched.ready to signal when the hardware
> + * has died, which can mean that there's no valid runqueue for a @entity.
> + * This function returns -ENOENT in this case (which probably should be -EIO as
> + * a more meanigful return value).
> + *
> * Returns 0 for success, negative error code otherwise.
> */
> int drm_sched_job_init(struct drm_sched_job *job,
> struct drm_sched_entity *entity,
> void *owner)
> {
> - struct drm_gpu_scheduler *sched;
> -
> drm_sched_entity_select_rq(entity);
> if (!entity->rq)
> return -ENOENT;
>
> - sched = entity->rq->sched;
> -
> - job->sched = sched;
> job->entity = entity;
> - job->s_priority = entity->rq - sched->sched_rq;
> - job->s_fence = drm_sched_fence_create(entity, owner);
> + job->s_fence = drm_sched_fence_alloc(entity, owner);
> if (!job->s_fence)
> return -ENOMEM;
> - job->id = atomic64_inc_return(&sched->job_id_count);
>
> INIT_LIST_HEAD(&job->list);
>
> @@ -606,13 +608,58 @@ int drm_sched_job_init(struct drm_sched_job *job,
> EXPORT_SYMBOL(drm_sched_job_init);
>
> /**
> - * drm_sched_job_cleanup - clean up scheduler job resources
> + * drm_sched_job_arm - arm a scheduler job for execution
> + * @job: scheduler job to arm
> + *
> + * This arms a scheduler job for execution. Specifically it initializes the
> + * &drm_sched_job.s_fence of @job, so that it can be attached to struct dma_resv
> + * or other places that need to track the completion of this job.
> + *
> + * Refer to drm_sched_entity_push_job() documentation for locking
> + * considerations.
> *
> + * This can only be called if drm_sched_job_init() succeeded.
> + */
> +void drm_sched_job_arm(struct drm_sched_job *job)
> +{
> + struct drm_gpu_scheduler *sched;
> + struct drm_sched_entity *entity = job->entity;
> +
> + BUG_ON(!entity);
> +
> + sched = entity->rq->sched;
> +
> + job->sched = sched;
> + job->s_priority = entity->rq - sched->sched_rq;
> + job->id = atomic64_inc_return(&sched->job_id_count);
> +
> + drm_sched_fence_init(job->s_fence, job->entity);
> +}
> +EXPORT_SYMBOL(drm_sched_job_arm);
> +
> +/**
> + * drm_sched_job_cleanup - clean up scheduler job resources
> * @job: scheduler job to clean up
> + *
> + * Cleans up the resources allocated with drm_sched_job_init().
> + *
> + * Drivers should call this from their error unwind code if @job is aborted
> + * before drm_sched_job_arm() is called.
> + *
> + * After that point of no return @job is committed to be executed by the
> + * scheduler, and this function should be called from the
> + * &drm_sched_backend_ops.free_job callback.
> */
> void drm_sched_job_cleanup(struct drm_sched_job *job)
> {
> - dma_fence_put(&job->s_fence->finished);
> + if (kref_read(&job->s_fence->finished.refcount)) {
> + /* drm_sched_job_arm() has been called */
> + dma_fence_put(&job->s_fence->finished);
> + } else {
> + /* aborted job before committing to run it */
> + drm_sched_fence_free(&job->s_fence->finished.rcu);
> + }
> +
> job->s_fence = NULL;
> }
> EXPORT_SYMBOL(drm_sched_job_cleanup);
> diff --git a/drivers/gpu/drm/v3d/v3d_gem.c b/drivers/gpu/drm/v3d/v3d_gem.c
> index 5689da118197..2e808097b4d1 100644
> --- a/drivers/gpu/drm/v3d/v3d_gem.c
> +++ b/drivers/gpu/drm/v3d/v3d_gem.c
> @@ -480,6 +480,8 @@ v3d_push_job(struct v3d_file_priv *v3d_priv,
> if (ret)
> return ret;
>
> + drm_sched_job_arm(&job->base);
> +
> job->done_fence = dma_fence_get(&job->base.s_fence->finished);
>
> /* put by scheduler job completion */
> diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h
> index 88ae7f331bb1..83afc3aa8e2f 100644
> --- a/include/drm/gpu_scheduler.h
> +++ b/include/drm/gpu_scheduler.h
> @@ -348,6 +348,7 @@ void drm_sched_fini(struct drm_gpu_scheduler *sched);
> int drm_sched_job_init(struct drm_sched_job *job,
> struct drm_sched_entity *entity,
> void *owner);
> +void drm_sched_job_arm(struct drm_sched_job *job);
> void drm_sched_entity_modify_sched(struct drm_sched_entity *entity,
> struct drm_gpu_scheduler **sched_list,
> unsigned int num_sched_list);
> @@ -387,8 +388,12 @@ void drm_sched_entity_set_priority(struct drm_sched_entity *entity,
> enum drm_sched_priority priority);
> bool drm_sched_entity_is_ready(struct drm_sched_entity *entity);
>
> -struct drm_sched_fence *drm_sched_fence_create(
> +struct drm_sched_fence *drm_sched_fence_alloc(
> struct drm_sched_entity *s_entity, void *owner);
> +void drm_sched_fence_init(struct drm_sched_fence *fence,
> + struct drm_sched_entity *entity);
> +void drm_sched_fence_free(struct rcu_head *rcu);
> +
> void drm_sched_fence_scheduled(struct drm_sched_fence *fence);
> void drm_sched_fence_finished(struct drm_sched_fence *fence);
>