提交 3d106fba 编写于 作者: S Shaohua Li 提交者: Jens Axboe

block CFQ: avoid moving request to different queue

request is queued in cfqq->fifo list. Looks it's possible we are moving a
request from one cfqq to another in request merge case. In such case, adjusting
the fifo list order doesn't make sense and is impossible if we don't iterate
the whole fifo list.

My test does hit one case the two cfqq are different, but didn't cause kernel
crash, maybe it's because fifo list isn't used frequently. Anyway, from the
code logic, this is buggy.

I thought we can re-enable the recusive merge logic after this is fixed.
Signed-off-by: NShaohua Li <shli@fusionio.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
上级 3d70f8c6
......@@ -1973,7 +1973,8 @@ cfq_merged_requests(struct request_queue *q, struct request *rq,
* reposition in fifo if next is older than rq
*/
if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) &&
time_before(rq_fifo_time(next), rq_fifo_time(rq))) {
time_before(rq_fifo_time(next), rq_fifo_time(rq)) &&
cfqq == RQ_CFQQ(next)) {
list_move(&rq->queuelist, &next->queuelist);
rq_set_fifo_time(rq, rq_fifo_time(next));
}
......
Markdown is supported
0% .
You are about to add 0 people to the discussion. Proceed with caution.
先完成此消息的编辑!
想要评论请 注册