From: Jens Axboe <axboe@kernel.dk>
To: Ming Lei <ming.lei@redhat.com>, Christoph Hellwig <hch@lst.de>
Cc: Kanchan Joshi <joshi.k@samsung.com>,
io-uring@vger.kernel.org, linux-nvme@lists.infradead.org,
asml.silence@gmail.com, mcgrof@kernel.org, shr@fb.com,
joshiiitr@gmail.com, anuj20.g@samsung.com, gost.dev@samsung.com
Subject: Re: [PATCH v5 2/6] block: wire-up support for passthrough plugging
Date: Thu, 12 May 2022 06:31:18 -0600 [thread overview]
Message-ID: <74e33b5d-71ce-1309-7897-e5e8ad2ed778@kernel.dk> (raw)
In-Reply-To: <YnzI7CgI+KOHNKPb@T590>
On 5/12/22 2:44 AM, Ming Lei wrote:
> On Thu, May 12, 2022 at 10:09:12AM +0200, Christoph Hellwig wrote:
>> On Thu, May 12, 2022 at 01:25:24PM +0800, Ming Lei wrote:
>>> This way may cause nested plugging, and breaks xfstests generic/131.
>>> Also may cause io hang since request can't be polled before flushing
>>> plug in blk_execute_rq().
>>
>> Looking at this again, yes blk_mq_request_bypass_insert is probably the
>> wrong place.
>>
>>> I'd suggest to apply the plug in blk_execute_rq_nowait(), such as:
>>
>> Do we really need the use_plug parameter and the extra helper? If
>> someone holds a plug over passthrough command submission I think
>> we can assume they actually do want to use it. Otherwise this does
>> indeed look like the better plan.
>
> use_plug is just for avoiding hang in blk_rq_poll_completion(), so
> I think we can bypass plug if one polled rq is executed inside
> blk_execute_rq().
Agree, and good catch. Do you want to send out a patch for this?
--
Jens Axboe
next prev parent reply other threads:[~2022-05-12 12:31 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20220511055306epcas5p3bf3b4c1e32d2bb43db12785bd7caf5da@epcas5p3.samsung.com>
2022-05-11 5:47 ` [PATCH v5 0/6] io_uring passthrough for nvme Kanchan Joshi
2022-05-11 5:47 ` [PATCH v5 1/6] fs,io_uring: add infrastructure for uring-cmd Kanchan Joshi
2022-05-11 12:42 ` Christoph Hellwig
2022-05-11 5:47 ` [PATCH v5 2/6] block: wire-up support for passthrough plugging Kanchan Joshi
2022-05-12 5:25 ` Ming Lei
2022-05-12 8:09 ` Christoph Hellwig
2022-05-12 8:44 ` Ming Lei
2022-05-12 12:31 ` Jens Axboe [this message]
2022-05-12 11:50 ` Anuj Gupta
2022-05-12 14:06 ` Ming Lei
2022-05-11 5:47 ` [PATCH v5 3/6] nvme: refactor nvme_submit_user_cmd() Kanchan Joshi
2022-05-11 5:47 ` [PATCH v5 4/6] nvme: wire-up uring-cmd support for io-passthru on char-device Kanchan Joshi
2022-05-11 5:47 ` [PATCH v5 5/6] nvme: add vectored-io support for uring-cmd Kanchan Joshi
2022-05-11 5:47 ` [PATCH v5 6/6] io_uring: finish IOPOLL/ioprio prep handler removal Kanchan Joshi
2022-05-11 6:54 ` Christoph Hellwig
2022-05-11 11:05 ` Kanchan Joshi
2022-05-11 12:38 ` Jens Axboe
2022-05-11 12:39 ` [PATCH v5 0/6] io_uring passthrough for nvme Jens Axboe
2022-05-11 13:14 ` Kanchan Joshi
2022-05-11 13:39 ` Jens Axboe
2022-05-11 13:48 ` Jens Axboe
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