Commit 3540d5e8 authored Nov 16, 2011 by Shaohua Li Committed by Jens Axboe Nov 16, 2011

block: avoid unnecessary plug list flush



get_request_wait() could sleep and flush the plug list.  If the list is
already flushed, don't flush again.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Reviewed-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

parent 0007a4c9

block/blk-core.c

+9 −7

Original line number	Diff line number	Diff line
		@@ -1379,7 +1379,8 @@ get_rq:
		*/
		if (list_empty(&plug->list))
		trace_block_plug(q);
		else if (!plug->should_sort) {
		else {
		if (!plug->should_sort) {
		struct request *__rq;

		__rq = list_entry_rq(plug->list.prev);
		@@ -1388,6 +1389,7 @@ get_rq:
		}
		if (request_count >= BLK_MAX_REQUEST_COUNT)
		blk_flush_plug_list(plug, false);
		}
		list_add_tail(&req->queuelist, &plug->list);
		drive_stat_acct(req, 1);
		} else {