From 3540d5e89b2ac268fcfc9b07a50a9ba4acc2e5e5 Mon Sep 17 00:00:00 2001
From: Shaohua Li <shaohua.li@intel.com>
Date: Wed, 16 Nov 2011 09:21:50 +0100
Subject: 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>
---
block/blk-core.c | 16 +++++++++-------
1 file changed, 9 insertions(+), 7 deletions(-)
(limited to 'block/blk-core.c')
diff --git a/block/blk-core.c b/block/blk-core.c
index f43c8a5840ae..6403c12f8aad 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1379,15 +1379,17 @@ get_rq:
*/
if (list_empty(&plug->list))
trace_block_plug(q);
- else if (!plug->should_sort) {
- struct request *__rq;
+ else {
+ if (!plug->should_sort) {
+ struct request *__rq;
- __rq = list_entry_rq(plug->list.prev);
- if (__rq->q != q)
- plug->should_sort = 1;
+ __rq = list_entry_rq(plug->list.prev);
+ if (__rq->q != q)
+ plug->should_sort = 1;
+ }
+ if (request_count >= BLK_MAX_REQUEST_COUNT)
+ blk_flush_plug_list(plug, false);
}
- 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 {
--
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