From: "jianchao.wang" <jianchao.w.wang@oracle.com>
To: Ming Lei <ming.lei@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>, Keith Busch <keith.busch@intel.com>,
Sagi Grimberg <sagi@grimberg.me>,
linux-nvme@lists.infradead.org, linux-block@vger.kernel.org,
Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH 1/2] nvme: pci: simplify timeout handling
Date: Sat, 28 Apr 2018 22:00:17 +0800 [thread overview]
Message-ID: <18b7ab23-f0d6-6765-021a-28c225f8a990@oracle.com> (raw)
In-Reply-To: <20180427145708.GA2767@ming.t460p>
Hi ming
On 04/27/2018 10:57 PM, Ming Lei wrote:
> I may not understand your point, once blk_sync_queue() returns, the
> timer itself is deactivated, meantime the synced .nvme_timeout() only
> returns EH_NOT_HANDLED before the deactivation.
>
> That means this timer won't be expired any more, so could you explain
> a bit why timeout can come again after blk_sync_queue() returns
Please consider the following case:
blk_sync_queue
-> del_timer_sync
blk_mq_timeout_work
-> blk_mq_check_expired // return the timeout value
-> blk_mq_terninate_expired
-> .timeout //return EH_NOT_HANDLED
-> mod_timer // setup the timer again based on the result of blk_mq_check_expired
-> cancel_work_sync
So after the blk_sync_queue, the timer may come back again, then the timeout work.
Thanks
Jianchao
WARNING: multiple messages have this Message-ID (diff)
From: jianchao.w.wang@oracle.com (jianchao.wang)
Subject: [PATCH 1/2] nvme: pci: simplify timeout handling
Date: Sat, 28 Apr 2018 22:00:17 +0800 [thread overview]
Message-ID: <18b7ab23-f0d6-6765-021a-28c225f8a990@oracle.com> (raw)
In-Reply-To: <20180427145708.GA2767@ming.t460p>
Hi ming
On 04/27/2018 10:57 PM, Ming Lei wrote:
> I may not understand your point, once blk_sync_queue() returns, the
> timer itself is deactivated, meantime the synced .nvme_timeout() only
> returns EH_NOT_HANDLED before the deactivation.
>
> That means this timer won't be expired any more, so could you explain
> a bit why timeout can come again after blk_sync_queue() returns
Please consider the following case:
blk_sync_queue
-> del_timer_sync
blk_mq_timeout_work
-> blk_mq_check_expired // return the timeout value
-> blk_mq_terninate_expired
-> .timeout //return EH_NOT_HANDLED
-> mod_timer // setup the timer again based on the result of blk_mq_check_expired
-> cancel_work_sync
So after the blk_sync_queue, the timer may come back again, then the timeout work.
Thanks
Jianchao
next prev parent reply other threads:[~2018-04-28 14:00 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-26 12:39 [PATCH 0/2] nvme: pci: fix & improve timeout handling Ming Lei
2018-04-26 12:39 ` Ming Lei
2018-04-26 12:39 ` [PATCH 1/2] nvme: pci: simplify " Ming Lei
2018-04-26 12:39 ` Ming Lei
2018-04-26 15:07 ` jianchao.wang
2018-04-26 15:07 ` jianchao.wang
2018-04-26 15:57 ` Ming Lei
2018-04-26 15:57 ` Ming Lei
2018-04-26 16:16 ` Ming Lei
2018-04-26 16:16 ` Ming Lei
2018-04-27 1:37 ` jianchao.wang
2018-04-27 1:37 ` jianchao.wang
2018-04-27 14:57 ` Ming Lei
2018-04-27 14:57 ` Ming Lei
2018-04-28 14:00 ` jianchao.wang [this message]
2018-04-28 14:00 ` jianchao.wang
2018-04-28 21:57 ` Ming Lei
2018-04-28 21:57 ` Ming Lei
2018-04-28 22:27 ` Ming Lei
2018-04-28 22:27 ` Ming Lei
2018-04-29 1:36 ` Ming Lei
2018-04-29 1:36 ` Ming Lei
2018-04-29 2:21 ` jianchao.wang
2018-04-29 2:21 ` jianchao.wang
2018-04-29 14:13 ` Ming Lei
2018-04-29 14:13 ` Ming Lei
2018-04-27 17:51 ` Keith Busch
2018-04-27 17:51 ` Keith Busch
2018-04-28 3:50 ` Ming Lei
2018-04-28 3:50 ` Ming Lei
2018-04-28 13:35 ` Keith Busch
2018-04-28 13:35 ` Keith Busch
2018-04-28 14:31 ` jianchao.wang
2018-04-28 14:31 ` jianchao.wang
2018-04-28 21:39 ` Ming Lei
2018-04-28 21:39 ` Ming Lei
2018-04-30 19:52 ` Keith Busch
2018-04-30 19:52 ` Keith Busch
2018-04-30 23:14 ` Ming Lei
2018-04-30 23:14 ` Ming Lei
2018-05-08 15:30 ` Keith Busch
2018-05-08 15:30 ` Keith Busch
2018-05-10 20:52 ` Ming Lei
2018-05-10 20:52 ` Ming Lei
2018-05-10 21:05 ` Keith Busch
2018-05-10 21:05 ` Keith Busch
2018-05-10 21:10 ` Ming Lei
2018-05-10 21:10 ` Ming Lei
2018-05-10 21:18 ` Keith Busch
2018-05-10 21:18 ` Keith Busch
2018-05-10 21:24 ` Ming Lei
2018-05-10 21:24 ` Ming Lei
2018-05-10 21:44 ` Keith Busch
2018-05-10 21:44 ` Keith Busch
2018-05-10 21:50 ` Ming Lei
2018-05-10 21:50 ` Ming Lei
2018-05-10 21:53 ` Ming Lei
2018-05-10 21:53 ` Ming Lei
2018-05-10 22:03 ` Ming Lei
2018-05-10 22:03 ` Ming Lei
2018-05-10 22:43 ` Keith Busch
2018-05-10 22:43 ` Keith Busch
2018-05-11 0:14 ` Ming Lei
2018-05-11 0:14 ` Ming Lei
2018-05-11 2:10 ` Ming Lei
2018-05-11 2:10 ` Ming Lei
2018-04-26 12:39 ` [PATCH 2/2] nvme: pci: guarantee EH can make progress Ming Lei
2018-04-26 12:39 ` Ming Lei
2018-04-26 16:24 ` Keith Busch
2018-04-26 16:24 ` Keith Busch
2018-04-28 3:28 ` Ming Lei
2018-04-28 3:28 ` Ming Lei
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