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 <chris@chris-wilson.co.uk>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Eric Anholt <eric@anholt.net>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/gpu/drm/drm_gem.c

@@ -142,19 +142,6 @@ drm_gem_object_alloc(struct drm_device *dev, size_t size)
 	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;