From: Ming Lei <ming.lei@redhat.com>
To: Keith Busch <kbusch@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org, linux-nvme@lists.infradead.org,
Christoph Hellwig <hch@lst.de>, Sagi Grimberg <sagi@grimberg.me>,
Bart Van Assche <bvanassche@acm.org>,
Johannes Thumshirn <Johannes.Thumshirn@wdc.com>,
Chao Leng <lengchao@huawei.com>
Subject: Re: [PATCH V3 2/4] blk-mq: implement queue quiesce via percpu_ref for BLK_MQ_F_BLOCKING
Date: Wed, 9 Sep 2020 09:19:16 +0800 [thread overview]
Message-ID: <20200909011916.GB1465199@T590> (raw)
In-Reply-To: <20200908153108.GA3341002@dhcp-10-100-145-180.wdl.wdc.com>
On Tue, Sep 08, 2020 at 08:31:08AM -0700, Keith Busch wrote:
> On Tue, Sep 08, 2020 at 04:15:36PM +0800, Ming Lei wrote:
> > void blk_mq_quiesce_queue(struct request_queue *q)
> > {
> > - struct blk_mq_hw_ctx *hctx;
> > - unsigned int i;
> > - bool rcu = false;
> > + bool blocking = !!(q->tag_set->flags & BLK_MQ_F_BLOCKING);
> >
> > mutex_lock(&q->mq_quiesce_lock);
> >
> > - if (blk_queue_quiesced(q))
> > - goto exit;
>
> Why remove the 'goto exit' on this condition? There shouldn't be a need
> to synchronize dispatch again if a previous quiesce already did so.
Hammm, this change is supposed to be done in next patch of 'blk-mq: add tagset
quiesce interface'. The tagset quiesce interface starts to apply async quiesce,
so synchronize dispatch has to be done in blk_mq_quiesce_queue().
thanks,
Ming
next prev parent reply other threads:[~2020-09-09 1:19 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-08 8:15 [PATCH V3 0/4] blk-mq: implement queue quiesce via percpu_ref for BLK_MQ_F_BLOCKING Ming Lei
2020-09-08 8:15 ` [PATCH V3 1/4] blk-mq: serialize queue quiesce and unquiesce by mutex Ming Lei
2020-09-08 8:38 ` Hannes Reinecke
2020-09-08 11:31 ` Johannes Thumshirn
2020-09-08 17:54 ` Bart Van Assche
2020-09-09 1:16 ` Ming Lei
2020-09-08 8:15 ` [PATCH V3 2/4] blk-mq: implement queue quiesce via percpu_ref for BLK_MQ_F_BLOCKING Ming Lei
2020-09-08 8:44 ` Hannes Reinecke
2020-09-08 9:13 ` Chao Leng
2020-09-08 9:27 ` Ming Lei
2020-09-08 15:31 ` Keith Busch
2020-09-09 1:19 ` Ming Lei [this message]
2020-09-08 8:15 ` [PATCH V3 3/4] blk-mq: add tagset quiesce interface Ming Lei
2020-09-08 8:45 ` Hannes Reinecke
2020-09-08 8:15 ` [PATCH V3 4/4] nvme: use blk_mq_[un]quiesce_tagset Ming Lei
2020-09-08 8:46 ` Hannes Reinecke
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