drm/i915: Evict just the purgeable GTT entries on the first pass

Take two passes to evict everything whilst searching for sufficient free
space to bind the batchbuffer. After searching for sufficient free space
using LRU eviction, evict everything that is purgeable and try again.
Only then if there is insufficient free space (or the GTT is too badly
fragmented) evict everything from the aperture and try one last time.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

drivers/gpu/drm/i915/i915_drv.h

@@ -1073,8 +1073,8 @@ void i915_gem_release(struct drm_device * dev, struct drm_file *file_priv);
 /* i915_gem_evict.c */
 int i915_gem_evict_something(struct drm_device *dev, int min_size,
 			     unsigned alignment, bool mappable);
-int i915_gem_evict_everything(struct drm_device *dev);
-int i915_gem_evict_inactive(struct drm_device *dev);
+int i915_gem_evict_everything(struct drm_device *dev, bool purgeable_only);
+int i915_gem_evict_inactive(struct drm_device *dev, bool purgeable_only);
 
 /* i915_gem_tiling.c */
 void i915_gem_detect_bit_6_swizzle(struct drm_device *dev);

drivers/gpu/drm/i915/i915_gem.c

@@ -3519,7 +3519,8 @@ i915_gem_execbuffer_pin(struct drm_device *dev,
 	int ret, i, retry;
 
 	/* attempt to pin all of the buffers into the GTT */
-	for (retry = 0; retry < 2; retry++) {
+	retry = 0;
+	do {
 		ret = 0;
 		for (i = 0; i < count; i++) {
 			struct drm_i915_gem_exec_object2 *entry = &exec_list[i];
@@ -3567,18 +3568,18 @@ i915_gem_execbuffer_pin(struct drm_device *dev,
 		while (i--)
 			i915_gem_object_unpin(object_list[i]);
 
-		if (ret == 0)
-			break;
-
-		if (ret != -ENOSPC || retry)
+		if (ret != -ENOSPC || retry > 1)
 			return ret;
 
-		ret = i915_gem_evict_everything(dev);
+		/* First attempt, just clear anything that is purgeable.
+		 * Second attempt, clear the entire GTT.
+		 */
+		ret = i915_gem_evict_everything(dev, retry == 0);
 		if (ret)
 			return ret;
-	}
 
-	return 0;
+		retry++;
+	} while (1);
 }
 
 /* Throttle our rendering by waiting until the ring has completed our requests
@@ -4484,7 +4485,7 @@ i915_gem_idle(struct drm_device *dev)
 
 	/* Under UMS, be paranoid and evict. */
 	if (!drm_core_check_feature(dev, DRIVER_MODESET)) {
-		ret = i915_gem_evict_inactive(dev);
+		ret = i915_gem_evict_inactive(dev, false);
 		if (ret) {
 			mutex_unlock(&dev->struct_mutex);
 			return ret;

drivers/gpu/drm/i915/i915_gem_evict.c

@@ -42,7 +42,7 @@ mark_free(struct drm_i915_gem_object *obj_priv,
 
 int
 i915_gem_evict_something(struct drm_device *dev, int min_size,
-	 		 unsigned alignment, bool mappable)
+			 unsigned alignment, bool mappable)
 {
 	drm_i915_private_t *dev_priv = dev->dev_private;
 	struct list_head eviction_list, unwind_list;
@@ -54,7 +54,7 @@ i915_gem_evict_something(struct drm_device *dev, int min_size,
 	/* Re-check for free space after retiring requests */
 	if (mappable) {
 		if (drm_mm_search_free_in_range(&dev_priv->mm.gtt_space,
-				  		min_size, alignment, 0,
+						min_size, alignment, 0,
 						dev_priv->mm.gtt_mappable_end,
 						0))
 			return 0;
@@ -171,7 +171,7 @@ found:
 }
 
 int
-i915_gem_evict_everything(struct drm_device *dev)
+i915_gem_evict_everything(struct drm_device *dev, bool purgeable_only)
 {
 	drm_i915_private_t *dev_priv = dev->dev_private;
 	int ret;
@@ -192,38 +192,22 @@ i915_gem_evict_everything(struct drm_device *dev)
 
 	BUG_ON(!list_empty(&dev_priv->mm.flushing_list));
 
-	ret = i915_gem_evict_inactive(dev);
-	if (ret)
-		return ret;
-
-	lists_empty = (list_empty(&dev_priv->mm.inactive_list) &&
-		       list_empty(&dev_priv->mm.flushing_list) &&
-		       list_empty(&dev_priv->render_ring.active_list) &&
-		       list_empty(&dev_priv->bsd_ring.active_list) &&
-		       list_empty(&dev_priv->blt_ring.active_list));
-	BUG_ON(!lists_empty);
-
-	return 0;
+	return i915_gem_evict_inactive(dev, purgeable_only);
 }
 
 /** Unbinds all inactive objects. */
 int
-i915_gem_evict_inactive(struct drm_device *dev)
+i915_gem_evict_inactive(struct drm_device *dev, bool purgeable_only)
 {
 	drm_i915_private_t *dev_priv = dev->dev_private;
-
-	while (!list_empty(&dev_priv->mm.inactive_list)) {
-		struct drm_gem_object *obj;
-		int ret;
-
-		obj = &list_first_entry(&dev_priv->mm.inactive_list,
-					struct drm_i915_gem_object,
-					mm_list)->base;
-
-		ret = i915_gem_object_unbind(obj);
-		if (ret != 0) {
-			DRM_ERROR("Error unbinding object: %d\n", ret);
-			return ret;
+	struct drm_i915_gem_object *obj, *next;
+
+	list_for_each_entry_safe(obj, next,
+				 &dev_priv->mm.inactive_list, mm_list) {
+		if (!purgeable_only || obj->madv != I915_MADV_WILLNEED) {
+			int ret = i915_gem_object_unbind(&obj->base);
+			if (ret)
+				return ret;
 		}
 	}