From 3540d5e89b2ac268fcfc9b07a50a9ba4acc2e5e5 Mon Sep 17 00:00:00 2001 From: Shaohua Li Date: Wed, 16 Nov 2011 09:21:50 +0100 Subject: [PATCH] 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 Reviewed-by: Namhyung Kim Signed-off-by: Andrew Morton Signed-off-by: Jens Axboe --- block/blk-core.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/block/blk-core.c b/block/blk-core.c index f43c8a5840a..6403c12f8aa 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 { -- 2.34.1