From: Bart Van Assche <Bart.VanAssche@sandisk.com>
To: "hch@infradead.org" <hch@infradead.org>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
"axboe@fb.com" <axboe@fb.com>,
"ming.lei@redhat.com" <ming.lei@redhat.com>
Subject: Re: [PATCH v5 08/12] blk-mq: use QUEUE_FLAG_QUIESCED to quiesce queue
Date: Tue, 6 Jun 2017 16:03:48 +0000 [thread overview]
Message-ID: <1496765026.2692.8.camel@sandisk.com> (raw)
In-Reply-To: <20170606152210.22806-9-ming.lei@redhat.com>
On Tue, 2017-06-06 at 23:22 +0800, Ming Lei wrote:
> It is required that no dispatch can happen any more once
> blk_mq_quiesce_queue() returns, and we don't have such requirement
> on APIs of stopping queue.
>=20
> But blk_mq_quiesce_queue() still may not block/drain dispatch in the
> the case of BLK_MQ_S_START_ON_RUN, so use the new introduced flag of
> QUEUE_FLAG_QUIESCED and evaluate it inside RCU read-side critical
> sections for fixing this issue.
>=20
> Also blk_mq_quiesce_queue() is implemented via stopping queue, which
> limits its uses, and easy to cause race, because any queue restart in
> other paths may break blk_mq_quiesce_queue(). With the introduced
> flag of QUEUE_FLAG_QUIESCED, we don't need to depend on stopping queue
> for quiescing any more.
Reviewed-by: Bart Van Assche <Bart.VanAssche@sandisk.com>=
next prev parent reply other threads:[~2017-06-06 16:04 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-06 15:21 [PATCH v5 00/12] blk-mq: fix & improve queue quiescing Ming Lei
2017-06-06 15:21 ` [PATCH v5 01/12] blk-mq: pass correct hctx to blk_mq_try_issue_directly Ming Lei
2017-06-06 15:59 ` Bart Van Assche
2017-06-06 15:22 ` [PATCH v5 02/12] blk-mq: fix direct issue Ming Lei
2017-06-06 16:02 ` Bart Van Assche
2017-06-06 16:02 ` Bart Van Assche
2017-06-07 2:50 ` Ming Lei
2017-06-06 15:22 ` [PATCH v5 03/12] blk-mq: move blk_mq_quiesce_queue() into include/linux/blk-mq.h Ming Lei
2017-06-06 16:06 ` Bart Van Assche
2017-06-06 15:22 ` [PATCH v5 04/12] blk-mq: introduce blk_mq_quiesce_queue_nowait() Ming Lei
2017-06-06 15:22 ` [PATCH v5 05/12] blk-mq: introduce blk_mq_unquiesce_queue Ming Lei
2017-06-06 15:22 ` [PATCH v5 06/12] blk-mq: use the introduced blk_mq_unquiesce_queue() Ming Lei
2017-06-06 15:22 ` Ming Lei
2017-06-06 15:22 ` [PATCH v5 07/12] nvme: host: unquiesce queue in nvme_kill_queues() Ming Lei
2017-06-06 15:22 ` Ming Lei
2017-06-06 15:22 ` [PATCH v5 08/12] blk-mq: use QUEUE_FLAG_QUIESCED to quiesce queue Ming Lei
2017-06-06 16:03 ` Bart Van Assche [this message]
2017-06-06 15:22 ` [PATCH v5 09/12] blk-mq: update comments on blk_mq_quiesce_queue() Ming Lei
2017-06-06 15:22 ` [PATCH v5 10/12] blk-mq: don't stop queue for quiescing Ming Lei
2017-06-06 15:22 ` [PATCH v5 11/12] blk-mq: clarify dispatch may not be drained/blocked by stopping queue Ming Lei
2017-06-06 16:07 ` Bart Van Assche
2017-06-06 15:22 ` [PATCH v5 12/12] Revert "blk-mq: don't use sync workqueue flushing from drivers" Ming Lei
2017-06-06 16:03 ` [PATCH v5 00/12] blk-mq: fix & improve queue quiescing Jens Axboe
2017-06-13 2:15 ` Ming Lei
2017-06-18 20:26 ` Jens Axboe
2017-06-18 23:05 ` Bart Van Assche
2017-06-18 23:48 ` Jens Axboe
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