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| author | Shaohua Li <shaohua.li@intel.com> | 2011-11-16 09:21:50 +0100 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2011-11-16 09:21:50 +0100 |
| commit | 3540d5e89b2ac268fcfc9b07a50a9ba4acc2e5e5 (patch) | |
| tree | 10bb06165130e4ffe90bd990fbba497be8fb4e8a | |
| parent | 0007a4c90a11a5371c8b3f80b220fa402a399189 (diff) | |
| download | linux-stable-3540d5e89b2ac268fcfc9b07a50a9ba4acc2e5e5.tar.gz linux-stable-3540d5e89b2ac268fcfc9b07a50a9ba4acc2e5e5.tar.bz2 linux-stable-3540d5e89b2ac268fcfc9b07a50a9ba4acc2e5e5.zip | |
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>
| -rw-r--r-- | block/blk-core.c | 16 |
1 files changed, 9 insertions, 7 deletions
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 { |