Re: [Intel-gfx] [PATCH 05/15] drm/panfrost: Use xarray and helpers for depedency tracking

Boris Brezillon
2021-06-23T16:51:27Z

On Tue, 22 Jun 2021 18:55:01 +0200
Daniel Vetter <daniel.vetter@ffwll.ch> wrote:

> More consistency and prep work for the next patch.
>
> Aside: I wonder whether we shouldn't just move this entire xarray
> business into the scheduler so that not everyone has to reinvent the
> same wheels. Cc'ing some scheduler people for this too.
>
> v2: Correctly handle sched_lock since Lucas pointed out it's needed.
>
> v3: Rebase, dma_resv_get_excl_unlocked got renamed
>
> v4: Don't leak job references on failure (Steven).

Hehe, I had pretty much the same patch here [1].

Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>

[1]https://patchwork.kernel.org/project/dri-devel/patch/20210311092539.2405596-3-boris.brezillon@collabora.com/

>
> Cc: Lucas Stach <l.stach@pengutronix.de>
> Cc: "Christian König" <christian.koenig@amd.com>
> Cc: Luben Tuikov <luben.tuikov@amd.com>
> Cc: Alex Deucher <alexander.deucher@amd.com>
> Cc: Lee Jones <lee.jones@linaro.org>
> Cc: Steven Price <steven.price@arm.com>
> Cc: Rob Herring <robh@kernel.org>
> Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
> Cc: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
> Cc: Sumit Semwal <sumit.semwal@linaro.org>
> Cc: linux-media@vger.kernel.org
> Cc: linaro-mm-sig@lists.linaro.org
> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> ---
> drivers/gpu/drm/panfrost/panfrost_drv.c | 41 +++++++---------
> drivers/gpu/drm/panfrost/panfrost_job.c | 65 +++++++++++--------------
> drivers/gpu/drm/panfrost/panfrost_job.h | 8 ++-
> 3 files changed, 49 insertions(+), 65 deletions(-)
>
> diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c b/drivers/gpu/drm/panfrost/panfrost_drv.c
> index 075ec0ef746c..3ee828f1e7a5 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_drv.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_drv.c
> @@ -138,12 +138,6 @@ panfrost_lookup_bos(struct drm_device *dev,
> if (!job->bo_count)
> return 0;
>
> - job->implicit_fences = kvmalloc_array(job->bo_count,
> - sizeof(struct dma_fence *),
> - GFP_KERNEL | __GFP_ZERO);
> - if (!job->implicit_fences)
> - return -ENOMEM;
> -
> ret = drm_gem_objects_lookup(file_priv,
> (void __user *)(uintptr_t)args->bo_handles,
> job->bo_count, &job->bos);
> @@ -174,7 +168,7 @@ panfrost_lookup_bos(struct drm_device *dev,
> }
>
> /**
> - * panfrost_copy_in_sync() - Sets up job->in_fences[] with the sync objects
> + * panfrost_copy_in_sync() - Sets up job->deps with the sync objects
> * referenced by the job.
> * @dev: DRM device
> * @file_priv: DRM file for this fd
> @@ -194,22 +188,14 @@ panfrost_copy_in_sync(struct drm_device *dev,
> {
> u32 *handles;
> int ret = 0;
> - int i;
> + int i, in_fence_count;
>
> - job->in_fence_count = args->in_sync_count;
> + in_fence_count = args->in_sync_count;
>
> - if (!job->in_fence_count)
> + if (!in_fence_count)
> return 0;
>
> - job->in_fences = kvmalloc_array(job->in_fence_count,
> - sizeof(struct dma_fence *),
> - GFP_KERNEL | __GFP_ZERO);
> - if (!job->in_fences) {
> - DRM_DEBUG("Failed to allocate job in fences\n");
> - return -ENOMEM;
> - }
> -
> - handles = kvmalloc_array(job->in_fence_count, sizeof(u32), GFP_KERNEL);
> + handles = kvmalloc_array(in_fence_count, sizeof(u32), GFP_KERNEL);
> if (!handles) {
> ret = -ENOMEM;
> DRM_DEBUG("Failed to allocate incoming syncobj handles\n");
> @@ -218,16 +204,23 @@ panfrost_copy_in_sync(struct drm_device *dev,
>
> if (copy_from_user(handles,
> (void __user *)(uintptr_t)args->in_syncs,
> - job->in_fence_count * sizeof(u32))) {
> + in_fence_count * sizeof(u32))) {
> ret = -EFAULT;
> DRM_DEBUG("Failed to copy in syncobj handles\n");
> goto fail;
> }
>
> - for (i = 0; i < job->in_fence_count; i++) {
> + for (i = 0; i < in_fence_count; i++) {
> + struct dma_fence *fence;
> +
> ret = drm_syncobj_find_fence(file_priv, handles[i], 0, 0,
> - &job->in_fences[i]);
> - if (ret == -EINVAL)
> + &fence);
> + if (ret)
> + goto fail;
> +
> + ret = drm_gem_fence_array_add(&job->deps, fence);
> +
> + if (ret)
> goto fail;
> }
>
> @@ -265,6 +258,8 @@ static int panfrost_ioctl_submit(struct drm_device *dev, void *data,
>
> kref_init(&job->refcount);
>
> + xa_init_flags(&job->deps, XA_FLAGS_ALLOC);
> +
> job->pfdev = pfdev;
> job->jc = args->jc;
> job->requirements = args->requirements;
> diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c
> index 38f8580c19f1..71cd43fa1b36 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_job.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_job.c
> @@ -196,14 +196,21 @@ static void panfrost_job_hw_submit(struct panfrost_job *job, int js)
> job_write(pfdev, JS_COMMAND_NEXT(js), JS_COMMAND_START);
> }
>
> -static void panfrost_acquire_object_fences(struct drm_gem_object **bos,
> - int bo_count,
> - struct dma_fence **implicit_fences)
> +static int panfrost_acquire_object_fences(struct drm_gem_object **bos,
> + int bo_count,
> + struct xarray *deps)
> {
> - int i;
> + int i, ret;
>
> - for (i = 0; i < bo_count; i++)
> - implicit_fences[i] = dma_resv_get_excl_unlocked(bos[i]->resv);
> + for (i = 0; i < bo_count; i++) {
> + struct dma_fence *fence = dma_resv_get_excl_unlocked(bos[i]->resv);
> +
> + ret = drm_gem_fence_array_add(deps, fence);
> + if (ret)
> + return ret;
> + }
> +
> + return 0;
> }
>
> static void panfrost_attach_object_fences(struct drm_gem_object **bos,
> @@ -240,10 +247,14 @@ int panfrost_job_push(struct panfrost_job *job)
>
> job->render_done_fence = dma_fence_get(&job->base.s_fence->finished);
>
> - kref_get(&job->refcount); /* put by scheduler job completion */
> + ret = panfrost_acquire_object_fences(job->bos, job->bo_count,
> + &job->deps);
> + if (ret) {
> + mutex_unlock(&pfdev->sched_lock);
> + goto unlock;
> + }
>
> - panfrost_acquire_object_fences(job->bos, job->bo_count,
> - job->implicit_fences);
> + kref_get(&job->refcount); /* put by scheduler job completion */
>
> drm_sched_entity_push_job(&job->base, entity);
>
> @@ -262,18 +273,15 @@ static void panfrost_job_cleanup(struct kref *ref)
> {
> struct panfrost_job *job = container_of(ref, struct panfrost_job,
> refcount);
> + struct dma_fence *fence;
> + unsigned long index;
> unsigned int i;
>
> - if (job->in_fences) {
> - for (i = 0; i < job->in_fence_count; i++)
> - dma_fence_put(job->in_fences[i]);
> - kvfree(job->in_fences);
> - }
> - if (job->implicit_fences) {
> - for (i = 0; i < job->bo_count; i++)
> - dma_fence_put(job->implicit_fences[i]);
> - kvfree(job->implicit_fences);
> + xa_for_each(&job->deps, index, fence) {
> + dma_fence_put(fence);
> }
> + xa_destroy(&job->deps);
> +
> dma_fence_put(job->done_fence);
> dma_fence_put(job->render_done_fence);
>
> @@ -316,26 +324,9 @@ static struct dma_fence *panfrost_job_dependency(struct drm_sched_job *sched_job
> struct drm_sched_entity *s_entity)
> {
> struct panfrost_job *job = to_panfrost_job(sched_job);
> - struct dma_fence *fence;
> - unsigned int i;
> -
> - /* Explicit fences */
> - for (i = 0; i < job->in_fence_count; i++) {
> - if (job->in_fences[i]) {
> - fence = job->in_fences[i];
> - job->in_fences[i] = NULL;
> - return fence;
> - }
> - }
>
> - /* Implicit fences, max. one per BO */
> - for (i = 0; i < job->bo_count; i++) {
> - if (job->implicit_fences[i]) {
> - fence = job->implicit_fences[i];
> - job->implicit_fences[i] = NULL;
> - return fence;
> - }
> - }
> + if (!xa_empty(&job->deps))
> + return xa_erase(&job->deps, job->last_dep++);
>
> return NULL;
> }
> diff --git a/drivers/gpu/drm/panfrost/panfrost_job.h b/drivers/gpu/drm/panfrost/panfrost_job.h
> index bbd3ba97ff67..82306a03b57e 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_job.h
> +++ b/drivers/gpu/drm/panfrost/panfrost_job.h
> @@ -19,9 +19,9 @@ struct panfrost_job {
> struct panfrost_device *pfdev;
> struct panfrost_file_priv *file_priv;
>
> - /* Optional fences userspace can pass in for the job to depend on. */
> - struct dma_fence **in_fences;
> - u32 in_fence_count;
> + /* Contains both explicit and implicit fences */
> + struct xarray deps;
> + unsigned long last_dep;
>
> /* Fence to be signaled by IRQ handler when the job is complete. */
> struct dma_fence *done_fence;
> @@ -30,8 +30,6 @@ struct panfrost_job {
> __u32 requirements;
> __u32 flush_id;
>
> - /* Exclusive fences we have taken from the BOs to wait for */
> - struct dma_fence **implicit_fences;
> struct panfrost_gem_mapping **mappings;
> struct drm_gem_object **bos;
> u32 bo_count;