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charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 8/17/23 9:29 AM, Chengming Zhou wrote: > On 2023/8/17 22:50, Bart Van Assche wrote: >> On 8/17/23 07:41, kernel test robot wrote: >>> [ 222.622837][ T2216] statistics for priority 1: i 276 m 0 d 276 c 278 >>> [ 222.629307][ T2216] WARNING: CPU: 0 PID: 2216 at block/mq-deadline.c:680 dd_exit_sched (block/mq-deadline.c:680 (discriminator 3)) >> >> The above information shows that dd_inserted_request() has been called >> 276 times and also that dd_finish_request() has been called 278 times. > > Thanks much for your help. > > This patch indeed introduced a regression, postflush requests will be completed > twice, so here dd_finish_request() is more than dd_inserted_request(). > > diff --git a/block/blk-mq.c b/block/blk-mq.c > index a8c63bef8ff1..7cd47ffc04ce 100644 > --- a/block/blk-mq.c > +++ b/block/blk-mq.c > @@ -686,8 +686,10 @@ static void blk_mq_finish_request(struct request *rq) > { > struct request_queue *q = rq->q; > > - if (rq->rq_flags & RQF_USE_SCHED) > + if (rq->rq_flags & RQF_USE_SCHED) { > q->elevator->type->ops.finish_request(rq); > + rq->rq_flags &= ~RQF_USE_SCHED; > + } > } > > > Clear RQF_USE_SCHED flag here should fix this problem, which should be ok > since finish_request() is the last callback, this flag isn't needed anymore. > > Jens, should I send this diff as another patch or resend updated v3? I don't think this is the right solution, it makes all kinds of assumptions on what that flag is and when it's safe to clear it. It's a very fragile fix, I think we need to do better than that. -- Jens Axboe