mm: make generic_writepages() use plugging
This recovers a performance regression caused by the removal
of the per-device plugging.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index cc0ede1..24b7ac2 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -1039,11 +1039,17 @@
int generic_writepages(struct address_space *mapping,
struct writeback_control *wbc)
{
+ struct blk_plug plug;
+ int ret;
+
/* deal with chardevs and other special file */
if (!mapping->a_ops->writepage)
return 0;
- return write_cache_pages(mapping, wbc, __writepage, mapping);
+ blk_start_plug(&plug);
+ ret = write_cache_pages(mapping, wbc, __writepage, mapping);
+ blk_finish_plug(&plug);
+ return ret;
}
EXPORT_SYMBOL(generic_writepages);