[Intel-gfx] [PATCH] drm/i915: Pin relocations for the duration of constructing the execbuffer

[Chris Wilson]

As the execbuffer dispatch grows ever more complex and involves multiple
stages of moving objects into the aperture, we need to take greater care
that we do not evict our execbuffer objects prior to dispatch. This is
relatively simple as we can just keep the objects pinned for not just
the relocation but until we are finished.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Ben Widawsky <benjamin.widawsky at intel.com>
Cc: Daniel Vetter <daniel at ffwll.ch>
Cc: stable at vger.kernel.org
---
 drivers/gpu/drm/i915/i915_gem_execbuffer.c | 60 ++++++++++++++++--------------
 1 file changed, 32 insertions(+), 28 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index 885d595e0e02..b7e787fb4649 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -33,6 +33,9 @@
 #include "intel_drv.h"
 #include <linux/dma_remapping.h>
 
+#define  __EXEC_OBJECT_HAS_PIN (1<<31)
+#define  __EXEC_OBJECT_HAS_FENCE (1<<30)
+
 struct eb_vmas {
 	struct list_head vmas;
 	int and;
@@ -187,7 +190,28 @@ static struct i915_vma *eb_get_vma(struct eb_vmas *eb, unsigned long handle)
 	}
 }
 
-static void eb_destroy(struct eb_vmas *eb) {
+static void
+i915_gem_execbuffer_unreserve_vma(struct i915_vma *vma)
+{
+	struct drm_i915_gem_exec_object2 *entry;
+	struct drm_i915_gem_object *obj = vma->obj;
+
+	if (!drm_mm_node_allocated(&vma->node))
+		return;
+
+	entry = vma->exec_entry;
+
+	if (entry->flags & __EXEC_OBJECT_HAS_FENCE)
+		i915_gem_object_unpin_fence(obj);
+
+	if (entry->flags & __EXEC_OBJECT_HAS_PIN)
+		i915_gem_object_unpin(obj);
+
+	entry->flags &= ~(__EXEC_OBJECT_HAS_FENCE | __EXEC_OBJECT_HAS_PIN);
+}
+
+static void eb_destroy(struct eb_vmas *eb)
+{
 	while (!list_empty(&eb->vmas)) {
 		struct i915_vma *vma;
 
@@ -195,6 +219,7 @@ static void eb_destroy(struct eb_vmas *eb) {
 				       struct i915_vma,
 				       exec_list);
 		list_del_init(&vma->exec_list);
+		i915_gem_execbuffer_unreserve_vma(vma);
 		drm_gem_object_unreference(&vma->obj->base);
 	}
 	kfree(eb);
@@ -478,9 +503,6 @@ i915_gem_execbuffer_relocate(struct eb_vmas *eb,
 	return ret;
 }
 
-#define  __EXEC_OBJECT_HAS_PIN (1<<31)
-#define  __EXEC_OBJECT_HAS_FENCE (1<<30)
-
 static int
 need_reloc_mappable(struct i915_vma *vma)
 {
@@ -552,26 +574,6 @@ i915_gem_execbuffer_reserve_vma(struct i915_vma *vma,
 	return 0;
 }
 
-static void
-i915_gem_execbuffer_unreserve_vma(struct i915_vma *vma)
-{
-	struct drm_i915_gem_exec_object2 *entry;
-	struct drm_i915_gem_object *obj = vma->obj;
-
-	if (!drm_mm_node_allocated(&vma->node))
-		return;
-
-	entry = vma->exec_entry;
-
-	if (entry->flags & __EXEC_OBJECT_HAS_FENCE)
-		i915_gem_object_unpin_fence(obj);
-
-	if (entry->flags & __EXEC_OBJECT_HAS_PIN)
-		i915_gem_object_unpin(obj);
-
-	entry->flags &= ~(__EXEC_OBJECT_HAS_FENCE | __EXEC_OBJECT_HAS_PIN);
-}
-
 static int
 i915_gem_execbuffer_reserve(struct intel_ring_buffer *ring,
 			    struct list_head *vmas,
@@ -670,13 +672,14 @@ i915_gem_execbuffer_reserve(struct intel_ring_buffer *ring,
 				goto err;
 		}
 
-err:		/* Decrement pin count for bound objects */
-		list_for_each_entry(vma, vmas, exec_list)
-			i915_gem_execbuffer_unreserve_vma(vma);
-
+err:
 		if (ret != -ENOSPC || retry++)
 			return ret;
 
+		/* Decrement pin count for bound objects */
+		list_for_each_entry(vma, vmas, exec_list)
+			i915_gem_execbuffer_unreserve_vma(vma);
+
 		ret = i915_gem_evict_vm(vm, true);
 		if (ret)
 			return ret;
@@ -708,6 +711,7 @@ i915_gem_execbuffer_relocate_slow(struct drm_device *dev,
 	while (!list_empty(&eb->vmas)) {
 		vma = list_first_entry(&eb->vmas, struct i915_vma, exec_list);
 		list_del_init(&vma->exec_list);
+		i915_gem_execbuffer_unreserve_vma(vma);
 		drm_gem_object_unreference(&vma->obj->base);
 	}
 
-- 
1.8.4.4