Re: [PATCH 24/26] drm/i915: Update I915_GEM_BUSY IOCTL to understand composite fences

On 10/4/2021 3:06 PM, Matthew Brost wrote:

Parallel submission create composite fences (dma_fence_array) for excl / shared slots in objects. The I915_GEM_BUSY IOCTL checks these slots to determine the busyness of the object. Prior to patch it only check if the fence in the slot was a i915_request. Update the check to understand composite fences and correctly report the busyness.

Signed-off-by: Matthew Brost matthew.brost@intel.com

Reviewed-by: Daniele Ceraolo Spurio daniele.ceraolospurio@intel.com

Daniele

---

drivers/gpu/drm/i915/gem/i915_gem_busy.c | 60 +++++++++++++++---- .../gpu/drm/i915/gem/i915_gem_execbuffer.c | 5 +- drivers/gpu/drm/i915/i915_request.h | 6 ++ 3 files changed, 58 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_busy.c b/drivers/gpu/drm/i915/gem/i915_gem_busy.c index 6234e17259c1..b89d173c62eb 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_busy.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_busy.c @@ -4,6 +4,8 @@

• Copyright © 2014-2016 Intel Corporation

*/

+#include <linux/dma-fence-array.h>

• #include "gt/intel_engine.h"

  #include "i915_gem_ioctls.h"

@@ -36,7 +38,7 @@ static __always_inline u32 __busy_write_id(u16 id) }

static __always_inline unsigned int -__busy_set_if_active(const struct dma_fence *fence, u32 (*flag)(u16 id)) +__busy_set_if_active(struct dma_fence *fence, u32 (*flag)(u16 id)) { const struct i915_request *rq;

@@ -46,29 +48,63 @@ __busy_set_if_active(const struct dma_fence *fence, u32 (*flag)(u16 id)) * to eventually flush us, but to minimise latency just ask the * hardware. *

• * Note we only report on the status of native fences.
  

• * Note we only report on the status of native fences and we currently
  

• * have two native fences:
  

• *
  

• * 1. A composite fence (dma_fence_array) constructed of i915 requests
  

• * created during a parallel submission. In this case we deconstruct the
  

• * composite fence into individual i915 requests and check the status of
  

• * each request.
  

• *
  

• * 2. A single i915 request.
  

  */

• if (!dma_fence_is_i915(fence))

• if (dma_fence_is_array(fence)) {

• struct dma_fence_array *array = to_dma_fence_array(fence);
  

• struct dma_fence **child = array->fences;
  

• unsigned int nchild = array->num_fences;
  

• do {
  

• 	struct dma_fence *current_fence = *child++;
  

• 	/* Not an i915 fence, can't be busy per above */
  

• 	if (!dma_fence_is_i915(current_fence) ||
  

• 	    !test_bit(I915_FENCE_FLAG_COMPOSITE,
  

• 		      &current_fence->flags)) {
  

• 		return 0;
  

• 	}
  

• 	rq = to_request(current_fence);
  

• 	if (!i915_request_completed(rq)) {
  

• 		BUILD_BUG_ON(!typecheck(u16,
  

• 					rq->engine->uabi_class));
  

• 		return flag(rq->engine->uabi_class);
  

• 	}
  

• } while (--nchild);
  

• /* All requests in array complete, not busy */
  

  return 0;
• } else {

• if (!dma_fence_is_i915(fence))
  

• 	return 0;
  
  

• /* opencode to_request() in order to avoid const warnings */
• rq = container_of(fence, const struct i915_request, fence);
• if (i915_request_completed(rq))

• return 0;
  

• rq = to_request(fence);
  

• if (i915_request_completed(rq))
  

• 	return 0;
  
  

• /* Beware type-expansion follies! */
• BUILD_BUG_ON(!typecheck(u16, rq->engine->uabi_class));
• return flag(rq->engine->uabi_class);

• /* Beware type-expansion follies! */
  

• BUILD_BUG_ON(!typecheck(u16, rq->engine->uabi_class));
  

• return flag(rq->engine->uabi_class);
  

• } }

  static __always_inline unsigned int

-busy_check_reader(const struct dma_fence *fence) +busy_check_reader(struct dma_fence *fence) { return __busy_set_if_active(fence, __busy_read_flag); }

static __always_inline unsigned int -busy_check_writer(const struct dma_fence *fence) +busy_check_writer(struct dma_fence *fence) { if (!fence) return 0; diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c index 5c7fb6f68bbb..16276f406fd6 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c @@ -2988,8 +2988,11 @@ eb_composite_fence_create(struct i915_execbuffer *eb, int out_fence_fd) if (!fences) return ERR_PTR(-ENOMEM);

• for_each_batch_create_order(eb, i)

• for_each_batch_create_order(eb, i) { fences[i] = &eb->requests[i]->fence;

• __set_bit(I915_FENCE_FLAG_COMPOSITE,
  

• 	  &eb->requests[i]->fence.flags);
  

• }

  fence_array = dma_fence_array_create(eb->num_batches, fences,

diff --git a/drivers/gpu/drm/i915/i915_request.h b/drivers/gpu/drm/i915/i915_request.h index 24db8459376b..dc359242d1ae 100644 --- a/drivers/gpu/drm/i915/i915_request.h +++ b/drivers/gpu/drm/i915/i915_request.h @@ -156,6 +156,12 @@ enum { * submission / relationship encoutered an error. */ I915_FENCE_FLAG_SKIP_PARALLEL,

• /*

• * I915_FENCE_FLAG_COMPOSITE - Indicates fence is part of a composite
  

• * fence (dma_fence_array) and i915 generated for parallel submission.
  

• */
  

• I915_FENCE_FLAG_COMPOSITE, };

  /**