[Intel-gfx] [PATCH] drm/i915: Use engine->context_pin() to report the intel_ring

Oscar Mateo oscar.mateo at intel.com
Wed May 3 17:04:08 UTC 2017



On 05/03/2017 12:46 PM, Chris Wilson wrote:
> Since unifying ringbuffer/execlist submission to use
> engine->pin_context, we ensure that the intel_ring is available before
> we start constructing the request. We can therefore move the assignment
> of the request->ring to the central i915_gem_request_alloc() and not
> require it in every engine->request_alloc() callback. Another small step
> towards simplification (of the core, but at a cost of handling error
> pointers in less important callers of engine->pin_context).
>
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Oscar Mateo <oscar.mateo at intel.com>
> Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
> ---
>   drivers/gpu/drm/i915/gvt/scheduler.c         |  6 ++++--
>   drivers/gpu/drm/i915/i915_gem_request.c      |  9 ++++++---
>   drivers/gpu/drm/i915/i915_perf.c             |  7 +++++--
>   drivers/gpu/drm/i915/intel_engine_cs.c       |  7 ++++---
>   drivers/gpu/drm/i915/intel_lrc.c             | 14 ++++++--------
>   drivers/gpu/drm/i915/intel_ringbuffer.c      | 16 ++++++++--------
>   drivers/gpu/drm/i915/intel_ringbuffer.h      |  4 ++--
>   drivers/gpu/drm/i915/selftests/mock_engine.c |  8 ++++----
>   8 files changed, 39 insertions(+), 32 deletions(-)

Much better than my first impulse to reuse ce->ring in legacy ringbuffer 
mode

Reviewed-by: Oscar Mateo <oscar.mateo at intel.com>

> diff --git a/drivers/gpu/drm/i915/gvt/scheduler.c b/drivers/gpu/drm/i915/gvt/scheduler.c
> index 1256fe21850b..6ae286cb5804 100644
> --- a/drivers/gpu/drm/i915/gvt/scheduler.c
> +++ b/drivers/gpu/drm/i915/gvt/scheduler.c
> @@ -180,6 +180,7 @@ static int dispatch_workload(struct intel_vgpu_workload *workload)
>   	struct intel_engine_cs *engine = dev_priv->engine[ring_id];
>   	struct drm_i915_gem_request *rq;
>   	struct intel_vgpu *vgpu = workload->vgpu;
> +	struct intel_ring *ring;
>   	int ret;
>   
>   	gvt_dbg_sched("ring id %d prepare to dispatch workload %p\n",
> @@ -198,8 +199,9 @@ static int dispatch_workload(struct intel_vgpu_workload *workload)
>   	 * shadow_ctx pages invalid. So gvt need to pin itself. After update
>   	 * the guest context, gvt can unpin the shadow_ctx safely.
>   	 */
> -	ret = engine->context_pin(engine, shadow_ctx);
> -	if (ret) {
> +	ring = engine->context_pin(engine, shadow_ctx);
> +	if (IS_ERR(ring)) {
> +		ret = PTR_ERR(ring);
>   		gvt_vgpu_err("fail to pin shadow context\n");
>   		workload->status = ret;
>   		mutex_unlock(&dev_priv->drm.struct_mutex);
> diff --git a/drivers/gpu/drm/i915/i915_gem_request.c b/drivers/gpu/drm/i915/i915_gem_request.c
> index 8d2a5c8e5005..a988de74c398 100644
> --- a/drivers/gpu/drm/i915/i915_gem_request.c
> +++ b/drivers/gpu/drm/i915/i915_gem_request.c
> @@ -551,6 +551,7 @@ i915_gem_request_alloc(struct intel_engine_cs *engine,
>   {
>   	struct drm_i915_private *dev_priv = engine->i915;
>   	struct drm_i915_gem_request *req;
> +	struct intel_ring *ring;
>   	int ret;
>   
>   	lockdep_assert_held(&dev_priv->drm.struct_mutex);
> @@ -565,9 +566,10 @@ i915_gem_request_alloc(struct intel_engine_cs *engine,
>   	 * GGTT space, so do this first before we reserve a seqno for
>   	 * ourselves.
>   	 */
> -	ret = engine->context_pin(engine, ctx);
> -	if (ret)
> -		return ERR_PTR(ret);
> +	ring = engine->context_pin(engine, ctx);
> +	if (IS_ERR(ring))
> +		return ERR_CAST(ring);
> +	GEM_BUG_ON(!ring);
>   
>   	ret = reserve_seqno(engine);
>   	if (ret)
> @@ -633,6 +635,7 @@ i915_gem_request_alloc(struct intel_engine_cs *engine,
>   	req->i915 = dev_priv;
>   	req->engine = engine;
>   	req->ctx = ctx;
> +	req->ring = ring;
>   
>   	/* No zalloc, must clear what we need by hand */
>   	req->global_seqno = 0;
> diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
> index 060b171480d5..21e44942f561 100644
> --- a/drivers/gpu/drm/i915/i915_perf.c
> +++ b/drivers/gpu/drm/i915/i915_perf.c
> @@ -744,6 +744,7 @@ static int oa_get_render_ctx_id(struct i915_perf_stream *stream)
>   {
>   	struct drm_i915_private *dev_priv = stream->dev_priv;
>   	struct intel_engine_cs *engine = dev_priv->engine[RCS];
> +	struct intel_ring *ring;
>   	int ret;
>   
>   	ret = i915_mutex_lock_interruptible(&dev_priv->drm);
> @@ -755,9 +756,11 @@ static int oa_get_render_ctx_id(struct i915_perf_stream *stream)
>   	 *
>   	 * NB: implied RCS engine...
>   	 */
> -	ret = engine->context_pin(engine, stream->ctx);
> -	if (ret)
> +	ring = engine->context_pin(engine, stream->ctx);
> +	if (IS_ERR(ring)) {
> +		ret = PTR_ERR(ring);
>   		goto unlock;
> +	}
>   
>   	/* Explicitly track the ID (instead of calling i915_ggtt_offset()
>   	 * on the fly) considering the difference with gen8+ and
> diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c
> index 6d3d83876da9..483ed7635692 100644
> --- a/drivers/gpu/drm/i915/intel_engine_cs.c
> +++ b/drivers/gpu/drm/i915/intel_engine_cs.c
> @@ -469,6 +469,7 @@ static void intel_engine_cleanup_scratch(struct intel_engine_cs *engine)
>    */
>   int intel_engine_init_common(struct intel_engine_cs *engine)
>   {
> +	struct intel_ring *ring;
>   	int ret;
>   
>   	engine->set_default_submission(engine);
> @@ -480,9 +481,9 @@ int intel_engine_init_common(struct intel_engine_cs *engine)
>   	 * be available. To avoid this we always pin the default
>   	 * context.
>   	 */
> -	ret = engine->context_pin(engine, engine->i915->kernel_context);
> -	if (ret)
> -		return ret;
> +	ring = engine->context_pin(engine, engine->i915->kernel_context);
> +	if (IS_ERR(ring))
> +		return PTR_ERR(ring);
>   
>   	ret = intel_engine_init_breadcrumbs(engine);
>   	if (ret)
> diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
> index 0909549ad320..ab5bb22dc23d 100644
> --- a/drivers/gpu/drm/i915/intel_lrc.c
> +++ b/drivers/gpu/drm/i915/intel_lrc.c
> @@ -740,8 +740,9 @@ static void execlists_schedule(struct drm_i915_gem_request *request, int prio)
>   	/* XXX Do we need to preempt to make room for us and our deps? */
>   }
>   
> -static int execlists_context_pin(struct intel_engine_cs *engine,
> -				 struct i915_gem_context *ctx)
> +static struct intel_ring *
> +execlists_context_pin(struct intel_engine_cs *engine,
> +		      struct i915_gem_context *ctx)
>   {
>   	struct intel_context *ce = &ctx->engine[engine->id];
>   	unsigned int flags;
> @@ -751,7 +752,7 @@ static int execlists_context_pin(struct intel_engine_cs *engine,
>   	lockdep_assert_held(&ctx->i915->drm.struct_mutex);
>   
>   	if (ce->pin_count++)
> -		return 0;
> +		return ce->ring;
>   	GEM_BUG_ON(!ce->pin_count); /* no overflow please! */
>   
>   	if (!ce->state) {
> @@ -788,7 +789,7 @@ static int execlists_context_pin(struct intel_engine_cs *engine,
>   	ce->state->obj->mm.dirty = true;
>   
>   	i915_gem_context_get(ctx);
> -	return 0;
> +	return ce->ring;
>   
>   unpin_map:
>   	i915_gem_object_unpin_map(ce->state->obj);
> @@ -796,7 +797,7 @@ static int execlists_context_pin(struct intel_engine_cs *engine,
>   	__i915_vma_unpin(ce->state);
>   err:
>   	ce->pin_count = 0;
> -	return ret;
> +	return ERR_PTR(ret);
>   }
>   
>   static void execlists_context_unpin(struct intel_engine_cs *engine,
> @@ -833,9 +834,6 @@ static int execlists_request_alloc(struct drm_i915_gem_request *request)
>   	 */
>   	request->reserved_space += EXECLISTS_REQUEST_SIZE;
>   
> -	GEM_BUG_ON(!ce->ring);
> -	request->ring = ce->ring;
> -
>   	if (i915.enable_guc_submission) {
>   		/*
>   		 * Check that the GuC has space for the request before
> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
> index 00d60605cd89..3cafa85d62eb 100644
> --- a/drivers/gpu/drm/i915/intel_ringbuffer.c
> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
> @@ -1484,8 +1484,9 @@ alloc_context_vma(struct intel_engine_cs *engine)
>   	return vma;
>   }
>   
> -static int intel_ring_context_pin(struct intel_engine_cs *engine,
> -				  struct i915_gem_context *ctx)
> +static struct intel_ring *
> +intel_ring_context_pin(struct intel_engine_cs *engine,
> +		       struct i915_gem_context *ctx)
>   {
>   	struct intel_context *ce = &ctx->engine[engine->id];
>   	int ret;
> @@ -1493,7 +1494,7 @@ static int intel_ring_context_pin(struct intel_engine_cs *engine,
>   	lockdep_assert_held(&ctx->i915->drm.struct_mutex);
>   
>   	if (ce->pin_count++)
> -		return 0;
> +		return engine->buffer;
>   	GEM_BUG_ON(!ce->pin_count); /* no overflow please! */
>   
>   	if (!ce->state && engine->context_size) {
> @@ -1527,11 +1528,13 @@ static int intel_ring_context_pin(struct intel_engine_cs *engine,
>   		ce->initialised = true;
>   
>   	i915_gem_context_get(ctx);
> -	return 0;
> +
> +	/* One ringbuffer to rule them all */
> +	return engine->buffer;
>   
>   error:
>   	ce->pin_count = 0;
> -	return ret;
> +	return ERR_PTR(ret);
>   }
>   
>   static void intel_ring_context_unpin(struct intel_engine_cs *engine,
> @@ -1643,9 +1646,6 @@ static int ring_request_alloc(struct drm_i915_gem_request *request)
>   	 */
>   	request->reserved_space += LEGACY_REQUEST_SIZE;
>   
> -	GEM_BUG_ON(!request->engine->buffer);
> -	request->ring = request->engine->buffer;
> -
>   	cs = intel_ring_begin(request, 0);
>   	if (IS_ERR(cs))
>   		return PTR_ERR(cs);
> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
> index 3aed97bf0bb6..ec16fb6fde62 100644
> --- a/drivers/gpu/drm/i915/intel_ringbuffer.h
> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
> @@ -260,8 +260,8 @@ struct intel_engine_cs {
>   
>   	void		(*set_default_submission)(struct intel_engine_cs *engine);
>   
> -	int		(*context_pin)(struct intel_engine_cs *engine,
> -				       struct i915_gem_context *ctx);
> +	struct intel_ring *(*context_pin)(struct intel_engine_cs *engine,
> +					  struct i915_gem_context *ctx);
>   	void		(*context_unpin)(struct intel_engine_cs *engine,
>   					 struct i915_gem_context *ctx);
>   	int		(*request_alloc)(struct drm_i915_gem_request *req);
> diff --git a/drivers/gpu/drm/i915/selftests/mock_engine.c b/drivers/gpu/drm/i915/selftests/mock_engine.c
> index b8e53bdc3cc4..5b18a2dc19a8 100644
> --- a/drivers/gpu/drm/i915/selftests/mock_engine.c
> +++ b/drivers/gpu/drm/i915/selftests/mock_engine.c
> @@ -52,11 +52,12 @@ static void hw_delay_complete(unsigned long data)
>   	spin_unlock(&engine->hw_lock);
>   }
>   
> -static int mock_context_pin(struct intel_engine_cs *engine,
> -			    struct i915_gem_context *ctx)
> +static struct intel_ring *
> +mock_context_pin(struct intel_engine_cs *engine,
> +		 struct i915_gem_context *ctx)
>   {
>   	i915_gem_context_get(ctx);
> -	return 0;
> +	return engine->buffer;
>   }
>   
>   static void mock_context_unpin(struct intel_engine_cs *engine,
> @@ -72,7 +73,6 @@ static int mock_request_alloc(struct drm_i915_gem_request *request)
>   	INIT_LIST_HEAD(&mock->link);
>   	mock->delay = 0;
>   
> -	request->ring = request->engine->buffer;
>   	return 0;
>   }
>   



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