From: Jens Axboe <axboe@fb.com>
To: Christoph Hellwig <hch@lst.de>, Ming Lei <ming.lei@canonical.com>
Cc: James Bottomley <JBottomley@parallels.com>,
<linux-scsi@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
Douglas Gilbert <dgilbert@interlog.com>
Subject: Re: [PATCH] scsi-mq: fix hw queue hang caused by timeout
Date: Thu, 18 Sep 2014 11:03:26 -0600 [thread overview]
Message-ID: <541B105E.1030507@fb.com> (raw)
In-Reply-To: <20140918163549.GB3950@lst.de>
On 2014-09-18 10:35, Christoph Hellwig wrote:
> On Thu, Sep 18, 2014 at 11:59:10PM +0800, Ming Lei wrote:
>> If there are two requests or more timed out, the dispatch queue
>> is put into stopped state and never be recoverd, and there
>> is no such problem in non-mq mode.
>>
>> This patch trys to recover the stopped queue when the queue
>> becomes unbusy, then the following retries can move on.
>>
>> Basically this patch maintains same behavior for this situation
>> with non-mq mode.
>
> This looks somewhat similar to the issues that Doug reported, and I remember
> when he was last running into boot problems it was timeout related, too.
>
> As far as the implementation is concerned I think the correct fix is
> to clear the BLK_MQ_S_STOPPED queue flags in blk_mq_kick_requeue_list.
Since that's the kick part of the requeue, auto-starting the queue for
that makes a lot of sense. I say that's the way we go.
--
Jens Axboe
next prev parent reply other threads:[~2014-09-18 17:04 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-18 15:59 [PATCH] scsi-mq: fix hw queue hang caused by timeout Ming Lei
2014-09-18 16:35 ` Christoph Hellwig
2014-09-18 17:03 ` Jens Axboe [this message]
2014-09-19 13:07 ` Ming Lei
2014-09-19 14:18 ` Ming Lei
2014-09-19 14:21 ` Jens Axboe
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