[PATCH 5/6] drm/amdgpu: use fence-array for ctx release

[Edward O'Callaghan]

On 08/18/2016 05:50 PM, Chunming Zhou wrote:
> benifits:
> 1. don't block userspace release at all.
> 2. make sure userspace can look up dependency if fence isn't signaled.
> If they cannot find ctx, that means the dependecy is signaled.
> 
> Change-Id: I9184a7bb4f5bb6858c2dd49cfb113eeee159cf71
> Signed-off-by: Chunming Zhou <David1.Zhou at amd.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu.h     |  3 ++
>  drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c | 51 ++++++++++++++++++++++++++++++++-
>  2 files changed, 53 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> index 6d770c2..b6320e8 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> @@ -35,6 +35,7 @@
>  #include <linux/interval_tree.h>
>  #include <linux/hashtable.h>
>  #include <linux/fence.h>
> +#include <linux/fence-array.h>
>  
>  #include <ttm/ttm_bo_api.h>
>  #include <ttm/ttm_bo_driver.h>
> @@ -1025,6 +1026,8 @@ struct amdgpu_ctx_ring {
>  
>  struct amdgpu_ctx {
>  	struct kref		refcount;
> +	struct fence_cb         cb;
> +	struct work_struct      release_work;
>  	struct amdgpu_device    *adev;
>  	unsigned		reset_counter;
>  	spinlock_t		ring_lock;
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
> index 01d5612..23afe92 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
> @@ -27,6 +27,7 @@
>  
>  static DEFINE_MUTEX(amdgpu_ctx_lock);
>  extern struct idr amdgpu_ctx_idr;
> +static void amdgpu_ctx_release_work(struct work_struct *work);
>  
>  static int amdgpu_ctx_init(struct amdgpu_device *adev, struct amdgpu_ctx *ctx)
>  {
> @@ -37,6 +38,7 @@ static int amdgpu_ctx_init(struct amdgpu_device *adev, struct amdgpu_ctx *ctx)
>  	ctx->adev = adev;
>  	kref_init(&ctx->refcount);
>  	spin_lock_init(&ctx->ring_lock);
> +	INIT_WORK(&ctx->release_work, amdgpu_ctx_release_work);
>  	ctx->fences = kcalloc(amdgpu_sched_jobs * AMDGPU_MAX_RINGS,
>  			      sizeof(struct fence*), GFP_KERNEL);
>  	if (!ctx->fences)
> @@ -120,13 +122,60 @@ static int amdgpu_ctx_alloc(struct amdgpu_device *adev,
>  	return r;
>  }
>  
> +static void amdgpu_ctx_release_work(struct work_struct *work)
> +{
> +	struct amdgpu_ctx *ctx = container_of(work, struct amdgpu_ctx,
> +					      release_work);
> +	amdgpu_ctx_fini(ctx);
> +}
> +
> +static void amdgpu_ctx_release_cb(struct fence *f, struct fence_cb *cb)
> +{
> +	struct amdgpu_ctx *ctx = container_of(cb, struct amdgpu_ctx,
> +					      cb);
> +	schedule_work(&ctx->release_work);
> +	fence_put(f);
> +}
> +
>  static void amdgpu_ctx_do_release(struct kref *ref)
>  {
>  	struct amdgpu_ctx *ctx;
> +	struct fence **fences;
> +	struct fence_array *array;
> +	int i, j, k = 0, r;
>  
>  	ctx = container_of(ref, struct amdgpu_ctx, refcount);
>  
> -	amdgpu_ctx_fini(ctx);
> +	fences = kmalloc_array(sizeof(void *), AMDGPU_MAX_RINGS *
> +			       amdgpu_sched_jobs,
> +			       GFP_KERNEL);
> +	if (!fences)
> +		return;
> +	for (i = 0; i < AMDGPU_MAX_RINGS; ++i) {
> +		for (j = 0; j < amdgpu_sched_jobs; ++j) {
> +			if (ctx->rings[i].fences[j])
> +				fences[k++] = fence_get(ctx->rings[i].fences[j]);
> +		}
> +	}
> +	if (k == 0) {
> +		amdgpu_ctx_release_cb(NULL, &ctx->cb);
> +		kfree(fences);
> +		return;
> +	}
> +
> +	array = fence_array_create(k, fences, fence_context_alloc(1),
> +				   1, false);
> +	if (!array) {
> +		for (j = 0; j < k; ++j)
> +			fence_put(fences[j]);
> +		kfree(fences);
> +		return;
> +	}
> +	r = fence_add_callback(&array->base, &ctx->cb, amdgpu_ctx_release_cb);
> +	if (r == -ENOENT)
> +		amdgpu_ctx_release_cb(&array->base, &ctx->cb);
> +	else if (r)

Could be wrong but should this be (r < 0) ?

Kind Regards,
Edward.

> +		DRM_ERROR("fence add callback failed (%d)\n",  r);
>  }
>  
>  static int amdgpu_ctx_free(uint32_t id)
> 

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