From: Ming Lei <ming.lei@redhat.com>
To: Chao Leng <lengchao@huawei.com>
Cc: Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org, Sagi Grimberg <sagi@grimberg.me>,
Bart Van Assche <bvanassche@acm.org>,
Johannes Thumshirn <Johannes.Thumshirn@wdc.com>
Subject: Re: [PATCH V2 1/2] blk-mq: serialize queue quiesce and unquiesce by mutex
Date: Wed, 26 Aug 2020 16:54:22 +0800 [thread overview]
Message-ID: <20200826085422.GB116347@T590> (raw)
In-Reply-To: <751a63a2-9185-ba27-e84a-91b7cdd33ee7@huawei.com>
On Wed, Aug 26, 2020 at 03:51:25PM +0800, Chao Leng wrote:
> It doesn't matter. Because the reentry of quiesce&unquiesce queue is not
> safe, must be avoided by other mechanism. otherwise, exceptions may
> occur. Introduce mq_quiesce_lock looks saving possible synchronization
> waits, but it should not happen. If really happen, we need fix it.
Sagi mentioned there may be nested queue quiesce, so I add .mq_quiesce_lock
to make this usage easy to support, meantime avoid percpu_ref warning
in such usage.
Anyway, not see any problem with adding .mq_quiesce_lock, so I'd suggest to
move on with this way.
Thanks,
Ming
next prev parent reply other threads:[~2020-08-26 8:54 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-25 14:17 [PATCH V2 0/2] blk-mq: implement queue quiesce via percpu_ref for BLK_MQ_F_BLOCKING Ming Lei
2020-08-25 14:17 ` [PATCH V2 1/2] blk-mq: serialize queue quiesce and unquiesce by mutex Ming Lei
2020-08-26 7:51 ` Chao Leng
2020-08-26 8:54 ` Ming Lei [this message]
2020-08-26 15:36 ` Keith Busch
2020-08-26 16:23 ` Sagi Grimberg
2020-08-27 2:38 ` Ming Lei
2020-08-25 14:17 ` [PATCH V2 2/2] blk-mq: implement queue quiesce via percpu_ref for BLK_MQ_F_BLOCKING Ming Lei
2020-09-02 3:11 ` [PATCH V2 0/2] " Ming Lei
2020-09-02 17:52 ` Jens Axboe
2020-09-02 18:20 ` Sagi Grimberg
2020-09-03 0:41 ` Ming Lei
2020-09-03 0:35 ` Ming Lei
2020-09-03 12:37 ` Keith Busch
2020-09-03 13:10 ` Ming Lei
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200826085422.GB116347@T590 \
--to=ming.lei@redhat.com \
--cc=Johannes.Thumshirn@wdc.com \
--cc=axboe@kernel.dk \
--cc=bvanassche@acm.org \
--cc=lengchao@huawei.com \
--cc=linux-block@vger.kernel.org \
--cc=sagi@grimberg.me \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox