drm/i915: Truncate the shmem backing pages on purge
shmfs doesn't actually implement i_ops->truncate() so we were not
immedatiately releasing the backing pages when shrinking the gfx cache
under OOM. Instead use a combination of truncate_inode_pages() and
i_ops->truncate_range() as is used by shmem_delete_inode().
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Eric Anholt <eric@anholt.net>
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 8f3e0c1..4130621 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1505,9 +1505,16 @@
struct drm_i915_gem_object *obj_priv = to_intel_bo(obj);
struct inode *inode;
+ /* Our goal here is to return as much of the memory as
+ * is possible back to the system as we are called from OOM.
+ * To do this we must instruct the shmfs to drop all of its
+ * backing pages, *now*. Here we mirror the actions taken
+ * when by shmem_delete_inode() to release the backing store.
+ */
inode = obj->filp->f_path.dentry->d_inode;
- if (inode->i_op->truncate)
- inode->i_op->truncate (inode);
+ truncate_inode_pages(inode->i_mapping, 0);
+ if (inode->i_op->truncate_range)
+ inode->i_op->truncate_range(inode, 0, (loff_t)-1);
obj_priv->madv = __I915_MADV_PURGED;
}