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Commit 95ff7c7d authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915: Stash a pointer to the obj's resv in the vma 



During execbuf, a mandatory step is that we add this request (this
fence) to each object's reservation_object. Inside execbuf, we track the
vma, and to add the fence to the reservation_object then means having to
first chase the obj, incurring another cache miss. We can reduce the
 number of cache misses by stashing a pointer to the reservation_object
in the vma itself.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: default avatarJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170616140525.6394-1-chris@chris-wilson.co.uk
parent 7dd4f672

drivers/gpu/drm/i915/i915_gem_execbuffer.c

+12 −13
Original line number Diff line number Diff line
@@ -1192,17 +1192,17 @@ static int __reloc_gpu_alloc(struct i915_execbuffer *eb, 
	if (err)

		goto err_request;



	GEM_BUG_ON(!reservation_object_test_signaled_rcu(obj->resv, true));

	GEM_BUG_ON(!reservation_object_test_signaled_rcu(batch->resv, true));

	i915_vma_move_to_active(batch, rq, 0);

	reservation_object_lock(obj->resv, NULL);

	reservation_object_add_excl_fence(obj->resv, &rq->fence);

	reservation_object_unlock(obj->resv);

	reservation_object_lock(batch->resv, NULL);

	reservation_object_add_excl_fence(batch->resv, &rq->fence);

	reservation_object_unlock(batch->resv);

	i915_vma_unpin(batch);



	i915_vma_move_to_active(vma, rq, true);

	reservation_object_lock(vma->obj->resv, NULL);

	reservation_object_add_excl_fence(vma->obj->resv, &rq->fence);

	reservation_object_unlock(vma->obj->resv);

	reservation_object_lock(vma->resv, NULL);

	reservation_object_add_excl_fence(vma->resv, &rq->fence);

	reservation_object_unlock(vma->resv);



	rq->batch = batch;
@@ -1252,7 +1252,6 @@ relocate_entry(struct i915_vma *vma, 
	       struct i915_execbuffer *eb,

	       const struct i915_vma *target)

{

	struct drm_i915_gem_object *obj = vma->obj;

	u64 offset = reloc->offset;

	u64 target_offset = relocation_target(reloc, target);

	bool wide = eb->reloc_cache.use_64bit_reloc;
@@ -1260,7 +1259,7 @@ relocate_entry(struct i915_vma *vma, 


	if (!eb->reloc_cache.vaddr &&

	    (DBG_FORCE_RELOC == FORCE_GPU_RELOC ||

	     !reservation_object_test_signaled_rcu(obj->resv, true))) {

	     !reservation_object_test_signaled_rcu(vma->resv, true))) {

		const unsigned int gen = eb->reloc_cache.gen;

		unsigned int len;

		u32 *batch;
@@ -1320,7 +1319,7 @@ relocate_entry(struct i915_vma *vma, 
	}



repeat:

	vaddr = reloc_vaddr(obj, &eb->reloc_cache, offset >> PAGE_SHIFT);

	vaddr = reloc_vaddr(vma->obj, &eb->reloc_cache, offset >> PAGE_SHIFT);

	if (IS_ERR(vaddr))

		return PTR_ERR(vaddr);
@@ -1793,11 +1792,11 @@ static int eb_relocate(struct i915_execbuffer *eb) 
	return eb_relocate_slow(eb);

}



static void eb_export_fence(struct drm_i915_gem_object *obj,

static void eb_export_fence(struct i915_vma *vma,

			    struct drm_i915_gem_request *req,

			    unsigned int flags)

{

	struct reservation_object *resv = obj->resv;

	struct reservation_object *resv = vma->resv;



	/*

	 * Ignore errors from failing to allocate the new fence, we can't
@@ -1856,7 +1855,7 @@ static int eb_move_to_gpu(struct i915_execbuffer *eb) 
		const struct drm_i915_gem_exec_object2 *entry = &eb->exec[i];

		struct i915_vma *vma = exec_to_vma(entry);



		eb_export_fence(vma->obj, eb->request, entry->flags);

		eb_export_fence(vma, eb->request, entry->flags);

		if (unlikely(entry->flags & __EXEC_OBJECT_HAS_REF))

			i915_vma_put(vma);

	}

drivers/gpu/drm/i915/i915_vma.c

+1 −0
Original line number Diff line number Diff line
@@ -90,6 +90,7 @@ vma_create(struct drm_i915_gem_object *obj, 
	init_request_active(&vma->last_fence, NULL);

	vma->vm = vm;

	vma->obj = obj;

	vma->resv = obj->resv;

	vma->size = obj->base.size;

	vma->display_alignment = I915_GTT_MIN_ALIGNMENT;

drivers/gpu/drm/i915/i915_vma.h

+2 −1
Original line number Diff line number Diff line
@@ -50,6 +50,7 @@ struct i915_vma { 
	struct drm_i915_gem_object *obj;

	struct i915_address_space *vm;

	struct drm_i915_fence_reg *fence;

	struct reservation_object *resv; /** Alias of obj->resv */

	struct sg_table *pages;

	void __iomem *iomap;

	u64 size;
@@ -111,8 +112,8 @@ struct i915_vma { 
	/**

	 * Used for performing relocations during execbuffer insertion.

	 */

	struct hlist_node exec_node;

	struct drm_i915_gem_exec_object2 *exec_entry;

	struct hlist_node exec_node;

	u32 exec_handle;



	struct i915_gem_context *ctx;