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Date:   Tue, 27 Oct 2020 19:33:25 +0000
From:   Christoph Hellwig <hch@infradead.org>
To:     Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Cc:     linux-block@vger.kernel.org, axboe@kernel.dk, hch@infradead.org,
        joseph.qi@linux.alibaba.com
Subject: Re: [RFC] blk-mq: don't plug for HIPRI IO
Message-ID: <20201027193325.GA26382@infradead.org>
References: <20201027132951.121812-1-xiaoguang.wang@linux.alibaba.com>
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On Tue, Oct 27, 2020 at 09:29:51PM +0800, Xiaoguang Wang wrote:
> Commit cb700eb3faa4 ("block: don't plug for aio/O_DIRECT HIPRI IO")
> only does not call blk_start_plug() or blk_finish_plug for HIPRI IO
> in __blkdev_direct_IO(), but if upper layer subsystem, such as io_uring,
> still initializes valid plug, block layer may still plug HIPRI IO.
> To disable plug for HIPRI IO completely, do it in blk_mq_plug().

This creates a somewhat awkward layering.  Why can't io_uring just
stop creating a plug?