drm/i915: Tidy batch pool logic

Move the madvise logic out of the execbuffer main path into the
relatively rare allocation path, making the execbuffer manipulation less
fragile.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 19 insertions, 20 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem_batch_pool.c b/drivers/gpu/drm/i915/i915_gem_batch_pool.c
index 564be7c5ea7e..21f3356cc0ab 100644
--- a/drivers/gpu/drm/i915/i915_gem_batch_pool.c
+++ b/drivers/gpu/drm/i915/i915_gem_batch_pool.c
@@ -67,25 +67,23 @@ void i915_gem_batch_pool_fini(struct i915_gem_batch_pool *pool)
 					 struct drm_i915_gem_object,
 					 batch_pool_list);
 
-		WARN_ON(obj->active);
-
-		list_del_init(&obj->batch_pool_list);
+		list_del(&obj->batch_pool_list);
 		drm_gem_object_unreference(&obj->base);
 	}
 }
 
 /**
- * i915_gem_batch_pool_get() - select a buffer from the pool
+ * i915_gem_batch_pool_get() - allocate a buffer from the pool
  * @pool: the batch buffer pool
  * @size: the minimum desired size of the returned buffer
  *
- * Finds or allocates a batch buffer in the pool with at least the requested
- * size. The caller is responsible for any domain, active/inactive, or
- * purgeability management for the returned buffer.
+ * Returns an inactive buffer from @pool with at least @size bytes,
+ * with the pages pinned. The caller must i915_gem_object_unpin_pages()
+ * on the returned object.
  *
  * Note: Callers must hold the struct_mutex
  *
- * Return: the selected batch buffer object
+ * Return: the buffer object or an error pointer
  */
 struct drm_i915_gem_object *
 i915_gem_batch_pool_get(struct i915_gem_batch_pool *pool,
@@ -97,8 +95,7 @@ i915_gem_batch_pool_get(struct i915_gem_batch_pool *pool,
 	WARN_ON(!mutex_is_locked(&pool->dev->struct_mutex));
 
 	list_for_each_entry_safe(tmp, next,
-			&pool->cache_list, batch_pool_list) {
-
+				 &pool->cache_list, batch_pool_list) {
 		if (tmp->active)
 			continue;
 
@@ -114,25 +111,27 @@ i915_gem_batch_pool_get(struct i915_gem_batch_pool *pool,
 		 * but not 'too much' bigger. A better way to do this
 		 * might be to bucket the pool objects based on size.
 		 */
-		if (tmp->base.size >= size &&
-		    tmp->base.size <= (2 * size)) {
+		if (tmp->base.size >= size && tmp->base.size <= 2 * size) {
 			obj = tmp;
 			break;
 		}
 	}
 
-	if (!obj) {
+	if (obj == NULL) {
+		int ret;
+
 		obj = i915_gem_alloc_object(pool->dev, size);
-		if (!obj)
+		if (obj == NULL)
 			return ERR_PTR(-ENOMEM);
 
-		list_add_tail(&obj->batch_pool_list, &pool->cache_list);
-	}
-	else
-		/* Keep list in LRU order */
-		list_move_tail(&obj->batch_pool_list, &pool->cache_list);
+		ret = i915_gem_object_get_pages(obj);
+		if (ret)
+			return ERR_PTR(ret);
 
-	obj->madv = I915_MADV_WILLNEED;
+		obj->madv = I915_MADV_DONTNEED;
+	}
 
+	list_move_tail(&obj->batch_pool_list, &pool->cache_list);
+	i915_gem_object_pin_pages(obj);
 	return obj;
 }