From: Logan Gunthorpe <logang@deltatee.com>
To: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>,
linux-nvme@lists.infradead.org
Cc: kbusch@kernel.org, hch@lst.de, sagi@grimberg.me
Subject: Re: [PATCH V2 1/1] nvmet: don't use BLK_MQ_REQ_NOWAIT for passthru
Date: Tue, 20 Oct 2020 17:15:52 -0600 [thread overview]
Message-ID: <32159323-7473-c699-ff16-32380ae385e3@deltatee.com> (raw)
In-Reply-To: <20201020231404.9365-2-chaitanya.kulkarni@wdc.com>
On 2020-10-20 5:14 p.m., Chaitanya Kulkarni wrote:
> By default, we set the passthru request allocation flag such that it
> returns the error in the following code path and we fail the I/O when
> BLK_MQ_REQ_NOWAIT is used for request allocation :-
>
> nvme_alloc_request()
> blk_mq_alloc_request()
> blk_mq_queue_enter()
> if (flag & BLK_MQ_REQ_NOWAIT)
> return -EBUSY; <-- return if busy.
>
> On some controllers using BLK_MQ_REQ_NOWAIT ends up in I/O error where
> the controller is perfectly healthy and not in a degraded state.
>
> Block layer request allocation does allow us to wait instead of
> immediately returning the error when we BLK_MQ_REQ_NOWAIT flag is not
> used. This has shown to fix the I/O error problem reported under
> heavy random write workload.
>
> Remove the BLK_MQ_REQ_NOWAIT parameter for passthru request allocation
> which resolves this issue.
>
> Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Makes sense to me:
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
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next prev parent reply other threads:[~2020-10-20 23:16 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-20 23:14 [PATCH V2 0/1] nvmet: don't use BLK_MQ_REQ_NOWAIT for passthru Chaitanya Kulkarni
2020-10-20 23:14 ` [PATCH V2 1/1] " Chaitanya Kulkarni
2020-10-20 23:15 ` Logan Gunthorpe [this message]
2020-10-22 13:29 ` Christoph Hellwig
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