From: wenbo.wang@memblaze.com (Wenbo Wang)
Subject: [PATCH] NVMe: do not touch sq door bell if nvmeq has been suspended
Date: Wed, 3 Feb 2016 00:19:46 +0000 [thread overview]
Message-ID: <BJXPR01MB19992B07FA623851AC93FB7E0D00@BJXPR01MB199.CHNPR01.prod.partner.outlook.cn> (raw)
In-Reply-To: <20160202172503.GC10728@localhost.localdomain>
I used mdelay but not sleep.
-----Original Message-----
From: Keith Busch [mailto:keith.busch@intel.com]
Sent: Wednesday, February 3, 2016 1:25 AM
To: Wenbo Wang
Cc: Jens Axboe; Wenbo Wang; linux-kernel at vger.kernel.org; linux-nvme at lists.infradead.org; Wenwei.Tao
Subject: Re: [PATCH] NVMe: do not touch sq door bell if nvmeq has been suspended
On Tue, Feb 02, 2016@07:15:57AM +0000, Wenbo Wang wrote:
> Jens,
>
> I did the following test to validate the issue.
>
> 1. Modify code as below to increase the chance of races.
> Add 10s delay after nvme_dev_unmap() in nvme_dev_disable()
> Add 10s delay before __nvme_submit_cmd()
If running sync IO, preempt is disabled. You can't just put a 10 second delay there. Wouldn't you hit a "scheduling while atomic" bug instead?
If blk-mq is running the h/w context from its work queue, that might be a different issue. Maybe we can change the "cancel_delayed_work" to "cancel_delayed_work_sync" in blk_mq_stop_hw_queues.
If there's still a window where blk-mq can insert a request after the driver requested to stop queues, I think we should try to close it with the block layer.
next prev parent reply other threads:[~2016-02-03 0:19 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-01 15:42 [PATCH] NVMe: do not touch sq door bell if nvmeq has been suspended Wenbo Wang
2016-02-01 15:42 ` Wenbo Wang
2016-02-01 15:59 ` Busch, Keith
2016-02-01 15:59 ` Busch, Keith
2016-02-01 16:17 ` Wenbo Wang
2016-02-01 16:17 ` Wenbo Wang
2016-02-01 16:54 ` Jens Axboe
2016-02-01 16:54 ` Jens Axboe
2016-02-02 7:15 ` Wenbo Wang
2016-02-02 12:41 ` Sagi Grimberg
2016-02-02 12:41 ` Sagi Grimberg
2016-02-02 14:27 ` Keith Busch
2016-02-02 14:27 ` Keith Busch
2016-02-02 14:33 ` Sagi Grimberg
2016-02-02 14:33 ` Sagi Grimberg
2016-02-02 14:46 ` Keith Busch
2016-02-02 14:46 ` Keith Busch
2016-02-02 17:20 ` Sagi Grimberg
2016-02-02 17:20 ` Sagi Grimberg
2016-02-03 0:49 ` Wenbo Wang
2016-02-02 17:25 ` Keith Busch
2016-02-02 17:25 ` Keith Busch
2016-02-03 0:19 ` Wenbo Wang [this message]
2016-02-03 14:41 ` Keith Busch
2016-02-03 14:41 ` Keith Busch
2016-02-03 16:35 ` Wenbo Wang
2016-02-03 16:38 ` Keith Busch
2016-02-03 16:38 ` Keith Busch
2016-02-06 14:32 ` Wenbo Wang
2016-02-07 13:41 ` Sagi Grimberg
2016-02-07 13:41 ` Sagi Grimberg
2016-02-08 15:01 ` Keith Busch
2016-02-08 15:01 ` Keith Busch
2016-02-09 11:22 ` Wenbo Wang
2016-02-09 22:55 ` Keith Busch
2016-02-09 22:55 ` Keith Busch
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