drm/i915: Selectively enable self-reclaim

Having missed the ENOMEM return via i915_gem_fault(), there are probably
other paths that I also missed. By not enabling NORETRY by default these
paths can run the shrinker and take memory from the system (but not from
our own inactive lists because our shrinker can not run whilst we hold
the struct mutex) and this may allow the system to survive a little longer
whilst our drivers consume all available memory.

References:
OOM killer unexpectedly called with kernel 2.6.32
http://bugzilla.kernel.org/show_bug.cgi?id=14933

v2: Pass gfp into page mapping.
v3: Use new read_cache_page_gfp() instead of open-coding.

Signed-off-by: Chris Wilson <[e-mail]>
Cc: KOSAKI Motohiro <[e-mail]>
Cc: Hugh Dickins <[e-mail]>
Cc: Jesse Barnes <[e-mail]>
Cc: Eric Anholt <[e-mail]>
Cc: [e-mail]
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/gpu/drm/drm_gem.c

···
 	if (IS_ERR(obj->filp))
 		goto free;
 
-	/* Basically we want to disable the OOM killer and handle ENOMEM
-	 * ourselves by sacrificing pages from cached buffers.
-	 * XXX shmem_file_[gs]et_gfp_mask()
-	 */
-	mapping_set_gfp_mask(obj->filp->f_path.dentry->d_inode->i_mapping,
-			     GFP_HIGHUSER |
-			     __GFP_COLD |
-			     __GFP_FS |
-			     __GFP_RECLAIMABLE |
-			     __GFP_NORETRY |
-			     __GFP_NOWARN |
-			     __GFP_NOMEMALLOC);
-
 	kref_init(&obj->refcount);
 	kref_init(&obj->handlecount);
 	obj->size = size;

drivers/gpu/drm/i915/i915_debugfs.c

···
 	list_for_each_entry(obj_priv, &dev_priv->mm.active_list, list) {
 		obj = obj_priv->obj;
 		if (obj->read_domains & I915_GEM_DOMAIN_COMMAND) {
-		    ret = i915_gem_object_get_pages(obj);
+		    ret = i915_gem_object_get_pages(obj, 0);
 		    if (ret) {
 			    DRM_ERROR("Failed to get pages: %d\n", ret);
 			    spin_unlock(&dev_priv->mm.active_list_lock);

drivers/gpu/drm/i915/i915_drv.h

···
 void i915_gem_detach_phys_object(struct drm_device *dev,
 				 struct drm_gem_object *obj);
 void i915_gem_free_all_phys_object(struct drm_device *dev);
-int i915_gem_object_get_pages(struct drm_gem_object *obj);
+int i915_gem_object_get_pages(struct drm_gem_object *obj, gfp_t gfpmask);
 void i915_gem_object_put_pages(struct drm_gem_object *obj);
 void i915_gem_release(struct drm_device * dev, struct drm_file *file_priv);
 void i915_gem_object_flush_write_domain(struct drm_gem_object *obj);

drivers/gpu/drm/i915/i915_gem.c

···
 
 	mutex_lock(&dev->struct_mutex);
 
-	ret = i915_gem_object_get_pages(obj);
+	ret = i915_gem_object_get_pages(obj, 0);
 	if (ret != 0)
 		goto fail_unlock;
 
···
 	return ret;
 }
 
-static inline gfp_t
-i915_gem_object_get_page_gfp_mask (struct drm_gem_object *obj)
-{
-	return mapping_gfp_mask(obj->filp->f_path.dentry->d_inode->i_mapping);
-}
-
-static inline void
-i915_gem_object_set_page_gfp_mask (struct drm_gem_object *obj, gfp_t gfp)
-{
-	mapping_set_gfp_mask(obj->filp->f_path.dentry->d_inode->i_mapping, gfp);
-}
-
 static int
 i915_gem_object_get_pages_or_evict(struct drm_gem_object *obj)
 {
 	int ret;
 
-	ret = i915_gem_object_get_pages(obj);
+	ret = i915_gem_object_get_pages(obj, __GFP_NORETRY | __GFP_NOWARN);
 
 	/* If we've insufficient memory to map in the pages, attempt
 	 * to make some space by throwing out some old buffers.
 	 */
 	if (ret == -ENOMEM) {
 		struct drm_device *dev = obj->dev;
-		gfp_t gfp;
 
 		ret = i915_gem_evict_something(dev, obj->size);
 		if (ret)
 			return ret;
 
-		gfp = i915_gem_object_get_page_gfp_mask(obj);
-		i915_gem_object_set_page_gfp_mask(obj, gfp & ~__GFP_NORETRY);
-		ret = i915_gem_object_get_pages(obj);
-		i915_gem_object_set_page_gfp_mask (obj, gfp);
+		ret = i915_gem_object_get_pages(obj, 0);
 	}
 
 	return ret;
···
 
 	mutex_lock(&dev->struct_mutex);
 
-	ret = i915_gem_object_get_pages(obj);
+	ret = i915_gem_object_get_pages(obj, 0);
 	if (ret != 0)
 		goto fail_unlock;
 
···
 }
 
 int
-i915_gem_object_get_pages(struct drm_gem_object *obj)
+i915_gem_object_get_pages(struct drm_gem_object *obj,
+			  gfp_t gfpmask)
 {
 	struct drm_i915_gem_object *obj_priv = obj->driver_private;
 	int page_count, i;
···
 	inode = obj->filp->f_path.dentry->d_inode;
 	mapping = inode->i_mapping;
 	for (i = 0; i < page_count; i++) {
-		page = read_mapping_page(mapping, i, NULL);
+		page = read_cache_page_gfp(mapping, i,
+					   mapping_gfp_mask (mapping) |
+					   __GFP_COLD |
+					   gfpmask);
 		if (IS_ERR(page)) {
 			ret = PTR_ERR(page);
 			i915_gem_object_put_pages(obj);
···
 	drm_i915_private_t *dev_priv = dev->dev_private;
 	struct drm_i915_gem_object *obj_priv = obj->driver_private;
 	struct drm_mm_node *free_space;
-	bool retry_alloc = false;
+	gfp_t gfpmask =  __GFP_NORETRY | __GFP_NOWARN;
 	int ret;
 
 	if (obj_priv->madv != I915_MADV_WILLNEED) {
···
 	DRM_INFO("Binding object of size %zd at 0x%08x\n",
 		 obj->size, obj_priv->gtt_offset);
 #endif
-	if (retry_alloc) {
-		i915_gem_object_set_page_gfp_mask (obj,
-						   i915_gem_object_get_page_gfp_mask (obj) & ~__GFP_NORETRY);
-	}
-	ret = i915_gem_object_get_pages(obj);
-	if (retry_alloc) {
-		i915_gem_object_set_page_gfp_mask (obj,
-						   i915_gem_object_get_page_gfp_mask (obj) | __GFP_NORETRY);
-	}
+	ret = i915_gem_object_get_pages(obj, gfpmask);
 	if (ret) {
 		drm_mm_put_block(obj_priv->gtt_space);
 		obj_priv->gtt_space = NULL;
···
 			ret = i915_gem_evict_something(dev, obj->size);
 			if (ret) {
 				/* now try to shrink everyone else */
-				if (! retry_alloc) {
-				    retry_alloc = true;
-				    goto search_free;
+				if (gfpmask) {
+					gfpmask = 0;
+					goto search_free;
 				}
 
 				return ret;
···
 	if (!obj_priv->phys_obj)
 		return;
 
-	ret = i915_gem_object_get_pages(obj);
+	ret = i915_gem_object_get_pages(obj, 0);
 	if (ret)
 		goto out;
 
···
 	obj_priv->phys_obj = dev_priv->mm.phys_objs[id - 1];
 	obj_priv->phys_obj->cur_obj = obj;
 
-	ret = i915_gem_object_get_pages(obj);
+	ret = i915_gem_object_get_pages(obj, 0);
 	if (ret) {
 		DRM_ERROR("failed to get page list\n");
 		goto out;