[PATCH 7/14] drm/i915: use shmem_truncate_range

[Hugh Dickins]

The interface to ->truncate_range is changing very slightly:
once "tmpfs: take control of its truncate_range" has been applied,
this can be applied.  For now there is only a slight inefficiency
while this remains unapplied, but it will soon become essential
for managing shmem's use of swap.

Change i915_gem_object_truncate() to use shmem_truncate_range()
directly: which should also spare i915 later change if we switch
from inode_operations->truncate_range to file_operations->fallocate.

Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Keith Packard <keithp@xxxxxxxxxx>
Cc: Dave Airlie <airlied@xxxxxxxxxx>
---
 drivers/gpu/drm/i915/i915_gem.c |    7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

--- linux.orig/drivers/gpu/drm/i915/i915_gem.c	2011-06-05 18:37:13.589743574 -0700
+++ linux/drivers/gpu/drm/i915/i915_gem.c	2011-06-05 18:44:59.064050179 -0700
@@ -1694,13 +1694,10 @@ i915_gem_object_truncate(struct drm_i915
 	/* 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.
+	 * backing pages, *now*.
 	 */
 	inode = obj->base.filp->f_path.dentry->d_inode;
-	truncate_inode_pages(inode->i_mapping, 0);
-	if (inode->i_op->truncate_range)
-		inode->i_op->truncate_range(inode, 0, (loff_t)-1);
+	shmem_truncate_range(inode, 0, (loff_t)-1);
 
 	obj->madv = __I915_MADV_PURGED;
 }
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/