[Intel-gfx] [PATCH 41/46] drm/i915: Eliminate unnecessary VMA calls for multi-BB submission

[Matthew Brost <matthew.brost@intel.com>]

Certain VMA functions in the execbuf IOCTL only need to be called on
first or last BB of a multi-BB submission. eb_relocate() on the first
and eb_release_vmas() on the last. Doing so will save CPU / GPU cycles.

Signed-off-by: Matthew Brost <matthew.brost@intel.com>
---
 .../gpu/drm/i915/gem/i915_gem_execbuffer.c    | 127 +++++++++++-------
 .../i915/gem/selftests/i915_gem_execbuffer.c  |  14 +-
 2 files changed, 83 insertions(+), 58 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
index ecdb583cc2eb..70784779872a 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
@@ -270,7 +270,7 @@ struct i915_execbuffer {
 	/** list of vma that have execobj.relocation_count */
 	struct list_head relocs;
 
-	struct i915_gem_ww_ctx ww;
+	struct i915_gem_ww_ctx *ww;
 
 	/**
 	 * Track the most recently used object for relocations, as we
@@ -448,7 +448,7 @@ eb_pin_vma(struct i915_execbuffer *eb,
 		pin_flags |= PIN_GLOBAL;
 
 	/* Attempt to reuse the current location if available */
-	err = i915_vma_pin_ww(vma, &eb->ww, 0, 0, pin_flags);
+	err = i915_vma_pin_ww(vma, eb->ww, 0, 0, pin_flags);
 	if (err == -EDEADLK)
 		return err;
 
@@ -457,11 +457,11 @@ eb_pin_vma(struct i915_execbuffer *eb,
 			return err;
 
 		/* Failing that pick any _free_ space if suitable */
-		err = i915_vma_pin_ww(vma, &eb->ww,
-					     entry->pad_to_size,
-					     entry->alignment,
-					     eb_pin_flags(entry, ev->flags) |
-					     PIN_USER | PIN_NOEVICT);
+		err = i915_vma_pin_ww(vma, eb->ww,
+				      entry->pad_to_size,
+				      entry->alignment,
+				      eb_pin_flags(entry, ev->flags) |
+				      PIN_USER | PIN_NOEVICT);
 		if (unlikely(err))
 			return err;
 	}
@@ -643,9 +643,9 @@ static int eb_reserve_vma(struct i915_execbuffer *eb,
 			return err;
 	}
 
-	err = i915_vma_pin_ww(vma, &eb->ww,
-			   entry->pad_to_size, entry->alignment,
-			   eb_pin_flags(entry, ev->flags) | pin_flags);
+	err = i915_vma_pin_ww(vma, eb->ww,
+			      entry->pad_to_size, entry->alignment,
+			      eb_pin_flags(entry, ev->flags) | pin_flags);
 	if (err)
 		return err;
 
@@ -940,7 +940,7 @@ static int eb_lock_vmas(struct i915_execbuffer *eb)
 		struct eb_vma *ev = &eb->vma[i];
 		struct i915_vma *vma = ev->vma;
 
-		err = i915_gem_object_lock(vma->obj, &eb->ww);
+		err = i915_gem_object_lock(vma->obj, eb->ww);
 		if (err)
 			return err;
 	}
@@ -1020,12 +1020,13 @@ eb_get_vma(const struct i915_execbuffer *eb, unsigned long handle)
 	}
 }
 
-static void eb_release_vmas(struct i915_execbuffer *eb, bool final)
+static void eb_release_vmas(struct i915_execbuffer *eb, bool final,
+			    bool unreserve)
 {
 	const unsigned int count = eb->buffer_count;
 	unsigned int i;
 
-	for (i = 0; i < count; i++) {
+	for (i = 0; unreserve && i < count; i++) {
 		struct eb_vma *ev = &eb->vma[i];
 		struct i915_vma *vma = ev->vma;
 
@@ -1237,7 +1238,7 @@ static void *reloc_iomap(struct drm_i915_gem_object *obj,
 		if (err)
 			return ERR_PTR(err);
 
-		vma = i915_gem_object_ggtt_pin_ww(obj, &eb->ww, NULL, 0, 0,
+		vma = i915_gem_object_ggtt_pin_ww(obj, eb->ww, NULL, 0, 0,
 						  PIN_MAPPABLE |
 						  PIN_NONBLOCK /* NOWARN */ |
 						  PIN_NOEVICT);
@@ -1361,7 +1362,7 @@ static int __reloc_gpu_alloc(struct i915_execbuffer *eb,
 	}
 	eb->reloc_pool = NULL;
 
-	err = i915_gem_object_lock(pool->obj, &eb->ww);
+	err = i915_gem_object_lock(pool->obj, eb->ww);
 	if (err)
 		goto err_pool;
 
@@ -1380,7 +1381,7 @@ static int __reloc_gpu_alloc(struct i915_execbuffer *eb,
 		goto err_unmap;
 	}
 
-	err = i915_vma_pin_ww(batch, &eb->ww, 0, 0, PIN_USER | PIN_NONBLOCK);
+	err = i915_vma_pin_ww(batch, eb->ww, 0, 0, PIN_USER | PIN_NONBLOCK);
 	if (err)
 		goto err_unmap;
 
@@ -1402,7 +1403,7 @@ static int __reloc_gpu_alloc(struct i915_execbuffer *eb,
 			eb->reloc_context = ce;
 		}
 
-		err = intel_context_pin_ww(ce, &eb->ww);
+		err = intel_context_pin_ww(ce, eb->ww);
 		if (err)
 			goto err_unpin;
 
@@ -2017,8 +2018,8 @@ static noinline int eb_relocate_parse_slow(struct i915_execbuffer *eb,
 	}
 
 	/* We may process another execbuffer during the unlock... */
-	eb_release_vmas(eb, false);
-	i915_gem_ww_ctx_fini(&eb->ww);
+	eb_release_vmas(eb, false, true);
+	i915_gem_ww_ctx_fini(eb->ww);
 
 	if (rq) {
 		/* nonblocking is always false */
@@ -2062,7 +2063,7 @@ static noinline int eb_relocate_parse_slow(struct i915_execbuffer *eb,
 		err = eb_reinit_userptr(eb);
 
 err_relock:
-	i915_gem_ww_ctx_init(&eb->ww, true);
+	i915_gem_ww_ctx_init(eb->ww, true);
 	if (err)
 		goto out;
 
@@ -2119,8 +2120,8 @@ static noinline int eb_relocate_parse_slow(struct i915_execbuffer *eb,
 
 err:
 	if (err == -EDEADLK) {
-		eb_release_vmas(eb, false);
-		err = i915_gem_ww_ctx_backoff(&eb->ww);
+		eb_release_vmas(eb, false, true);
+		err = i915_gem_ww_ctx_backoff(eb->ww);
 		if (!err)
 			goto repeat_validate;
 	}
@@ -2152,7 +2153,7 @@ static noinline int eb_relocate_parse_slow(struct i915_execbuffer *eb,
 	return err;
 }
 
-static int eb_relocate_parse(struct i915_execbuffer *eb)
+static int eb_relocate_parse(struct i915_execbuffer *eb, bool first)
 {
 	int err;
 	struct i915_request *rq = NULL;
@@ -2189,14 +2190,16 @@ static int eb_relocate_parse(struct i915_execbuffer *eb)
 	/* only throttle once, even if we didn't need to throttle */
 	throttle = false;
 
-	err = eb_validate_vmas(eb);
-	if (err == -EAGAIN)
-		goto slow;
-	else if (err)
-		goto err;
+	if (first) {
+		err = eb_validate_vmas(eb);
+		if (err == -EAGAIN)
+			goto slow;
+		else if (err)
+			goto err;
+	}
 
 	/* The objects are in their final locations, apply the relocations. */
-	if (eb->args->flags & __EXEC_HAS_RELOC) {
+	if (eb->args->flags & __EXEC_HAS_RELOC && first) {
 		struct eb_vma *ev;
 
 		list_for_each_entry(ev, &eb->relocs, reloc_link) {
@@ -2211,13 +2214,13 @@ static int eb_relocate_parse(struct i915_execbuffer *eb)
 			goto slow;
 	}
 
-	if (!err)
+	if (!err && first)
 		err = eb_parse(eb);
 
 err:
 	if (err == -EDEADLK) {
-		eb_release_vmas(eb, false);
-		err = i915_gem_ww_ctx_backoff(&eb->ww);
+		eb_release_vmas(eb, false, true);
+		err = i915_gem_ww_ctx_backoff(eb->ww);
 		if (!err)
 			goto retry;
 	}
@@ -2398,7 +2401,7 @@ shadow_batch_pin(struct i915_execbuffer *eb,
 	if (IS_ERR(vma))
 		return vma;
 
-	err = i915_vma_pin_ww(vma, &eb->ww, 0, 0, flags);
+	err = i915_vma_pin_ww(vma, eb->ww, 0, 0, flags);
 	if (err)
 		return ERR_PTR(err);
 
@@ -2412,7 +2415,7 @@ static struct i915_vma *eb_dispatch_secure(struct i915_execbuffer *eb, struct i9
 	 * batch" bit. Hence we need to pin secure batches into the global gtt.
 	 * hsw should have this fixed, but bdw mucks it up again. */
 	if (eb->batch_flags & I915_DISPATCH_SECURE)
-		return i915_gem_object_ggtt_pin_ww(vma->obj, &eb->ww, NULL, 0, 0, 0);
+		return i915_gem_object_ggtt_pin_ww(vma->obj, eb->ww, NULL, 0, 0, 0);
 
 	return NULL;
 }
@@ -2458,7 +2461,7 @@ static int eb_parse(struct i915_execbuffer *eb)
 		eb->batch_pool = pool;
 	}
 
-	err = i915_gem_object_lock(pool->obj, &eb->ww);
+	err = i915_gem_object_lock(pool->obj, eb->ww);
 	if (err)
 		goto err;
 
@@ -2666,7 +2669,7 @@ static struct i915_request *eb_pin_engine(struct i915_execbuffer *eb, bool throt
 	 * GGTT space, so do this first before we reserve a seqno for
 	 * ourselves.
 	 */
-	err = intel_context_pin_ww(ce, &eb->ww);
+	err = intel_context_pin_ww(ce, eb->ww);
 	if (err)
 		return ERR_PTR(err);
 
@@ -3218,7 +3221,8 @@ i915_gem_do_execbuffer(struct drm_device *dev,
 		       unsigned int batch_number,
 		       struct dma_fence *in_fence,
 		       struct dma_fence *exec_fence,
-		       struct dma_fence **out_fence)
+		       struct dma_fence **out_fence,
+		       struct i915_gem_ww_ctx *ww)
 {
 	struct drm_i915_private *i915 = to_i915(dev);
 	struct i915_execbuffer eb;
@@ -3239,7 +3243,8 @@ i915_gem_do_execbuffer(struct drm_device *dev,
 
 	eb.exec = exec;
 	eb.vma = (struct eb_vma *)(exec + args->buffer_count + 1);
-	eb.vma[0].vma = NULL;
+	if (first)
+		eb.vma[0].vma = NULL;
 	eb.reloc_pool = eb.batch_pool = NULL;
 	eb.reloc_context = NULL;
 
@@ -3251,6 +3256,7 @@ i915_gem_do_execbuffer(struct drm_device *dev,
 	eb.batch_len = args->batch_len;
 	eb.trampoline = NULL;
 	eb.composite_fence = NULL;
+	eb.ww = ww;
 
 	eb.fences = NULL;
 	eb.num_fences = 0;
@@ -3269,9 +3275,14 @@ i915_gem_do_execbuffer(struct drm_device *dev,
 	if (err)
 		goto err_ext;
 
-	err = eb_create(&eb);
-	if (err)
-		goto err_ext;
+	if (first) {
+		err = eb_create(&eb);
+		if (err)
+			goto err_ext;
+	} else {
+		eb.lut_size = -eb.buffer_count;
+	}
+
 
 	GEM_BUG_ON(!eb.lut_size);
 
@@ -3286,15 +3297,22 @@ i915_gem_do_execbuffer(struct drm_device *dev,
 	if (unlikely(err))
 		goto err_context;
 
-	err = eb_lookup_vmas(&eb);
-	if (err) {
-		eb_release_vmas(&eb, true);
-		goto err_engine;
+	if (first) {
+		err = eb_lookup_vmas(&eb);
+		if (err) {
+			eb_release_vmas(&eb, true, true);
+			goto err_engine;
+		}
+
+	} else {
+		eb.batch = &eb.vma[eb.batch_index];
 	}
 
-	i915_gem_ww_ctx_init(&eb.ww, true);
 
-	err = eb_relocate_parse(&eb);
+	if (first)
+		i915_gem_ww_ctx_init(eb.ww, true);
+
+	err = eb_relocate_parse(&eb, first);
 	if (err) {
 		/*
 		 * If the user expects the execobject.offset and
@@ -3307,7 +3325,8 @@ i915_gem_do_execbuffer(struct drm_device *dev,
 		goto err_vma;
 	}
 
-	ww_acquire_done(&eb.ww.ctx);
+	if (first)
+		ww_acquire_done(&eb.ww->ctx);
 
 	batch = eb.batch->vma;
 
@@ -3410,11 +3429,12 @@ i915_gem_do_execbuffer(struct drm_device *dev,
 	i915_request_put(eb.request);
 
 err_vma:
-	eb_release_vmas(&eb, true);
+	eb_release_vmas(&eb, true, err || last);
 	if (eb.trampoline)
 		i915_vma_unpin(eb.trampoline);
 	WARN_ON(err == -EDEADLK);
-	i915_gem_ww_ctx_fini(&eb.ww);
+	if (err || last)
+		i915_gem_ww_ctx_fini(eb.ww);
 
 	if (eb.batch_pool)
 		intel_gt_buffer_pool_put(eb.batch_pool);
@@ -3476,6 +3496,7 @@ i915_gem_execbuffer2_ioctl(struct drm_device *dev, void *data,
 	const size_t count = args->buffer_count;
 	int err;
 	struct i915_gem_context *ctx;
+	struct i915_gem_ww_ctx ww;
 	struct intel_context *parent = NULL;
 	unsigned int num_batches = 1, i;
 	bool is_parallel = false;
@@ -3602,7 +3623,8 @@ i915_gem_execbuffer2_ioctl(struct drm_device *dev, void *data,
 				     0,
 				     in_fence,
 				     exec_fence,
-				     out_fences);
+				     out_fences,
+				     &ww);
 
 	for (i = 1; err == 0 && i < num_batches; i++)
 		err = i915_gem_do_execbuffer(dev, file, args, exec2_list,
@@ -3612,7 +3634,8 @@ i915_gem_execbuffer2_ioctl(struct drm_device *dev, void *data,
 					     i,
 					     NULL,
 					     NULL,
-					     out_fences);
+					     out_fences,
+					     &ww);
 
 	if (is_parallel)
 		mutex_unlock(&parent->parallel_submit);
diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_execbuffer.c
index 16162fc2782d..710d2700e5b4 100644
--- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_execbuffer.c
@@ -32,11 +32,11 @@ static int __igt_gpu_reloc(struct i915_execbuffer *eb,
 	if (IS_ERR(vma))
 		return PTR_ERR(vma);
 
-	err = i915_gem_object_lock(obj, &eb->ww);
+	err = i915_gem_object_lock(obj, eb->ww);
 	if (err)
 		return err;
 
-	err = i915_vma_pin_ww(vma, &eb->ww, 0, 0, PIN_USER | PIN_HIGH);
+	err = i915_vma_pin_ww(vma, eb->ww, 0, 0, PIN_USER | PIN_HIGH);
 	if (err)
 		return err;
 
@@ -106,10 +106,12 @@ static int __igt_gpu_reloc(struct i915_execbuffer *eb,
 static int igt_gpu_reloc(void *arg)
 {
 	struct i915_execbuffer eb;
+	struct i915_gem_ww_ctx ww;
 	struct drm_i915_gem_object *scratch;
 	int err = 0;
 	u32 *map;
 
+	eb.ww = &ww;
 	eb.i915 = arg;
 
 	scratch = i915_gem_object_create_internal(eb.i915, 4096);
@@ -141,20 +143,20 @@ static int igt_gpu_reloc(void *arg)
 		eb.reloc_pool = NULL;
 		eb.reloc_context = NULL;
 
-		i915_gem_ww_ctx_init(&eb.ww, false);
+		i915_gem_ww_ctx_init(eb.ww, false);
 retry:
-		err = intel_context_pin_ww(eb.context, &eb.ww);
+		err = intel_context_pin_ww(eb.context, eb.ww);
 		if (!err) {
 			err = __igt_gpu_reloc(&eb, scratch);
 
 			intel_context_unpin(eb.context);
 		}
 		if (err == -EDEADLK) {
-			err = i915_gem_ww_ctx_backoff(&eb.ww);
+			err = i915_gem_ww_ctx_backoff(eb.ww);
 			if (!err)
 				goto retry;
 		}
-		i915_gem_ww_ctx_fini(&eb.ww);
+		i915_gem_ww_ctx_fini(eb.ww);
 
 		if (eb.reloc_pool)
 			intel_gt_buffer_pool_put(eb.reloc_pool);
-- 
2.28.0