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Date:   Mon, 20 Mar 2023 14:56:49 -0600
From:   Keith Busch <kbusch@kernel.org>
To:     Keith Busch <kbusch@meta.com>
Cc:     linux-block@vger.kernel.org, Jens Axboe <axboe@kernel.dk>,
        io-uring@vger.kernel.org, Pavel Begunkov <asml.silence@gmail.com>
Subject: Re: [PATCHv2] blk-mq: remove hybrid polling
Message-ID: <ZBjIkXZLR2fSOyqX@kbusch-mbp.dhcp.thefacebook.com>
References: <20230320194926.3353144-1-kbusch@meta.com>
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On Mon, Mar 20, 2023 at 12:49:26PM -0700, Keith Busch wrote:
> From: Keith Busch <kbusch@kernel.org>
> 
> io_uring provides the only way user space can poll completions, and that
> always sets BLK_POLL_NOSLEEP. This effectively makes hybrid polling dead
> code, so remove it and everything supporting it.

Hybrid polling was effectively killed off with 9650b453a3d4b1, "block: ignore
RWF_HIPRI hint for sync dio", so we could add a "Fixes: " for that. It was
still potentially reachable through io_uring until d729cf9acb93119, "io_uring:
don't sleep when polling for I/O", but hybrid polling probably should not have
been reachable through that async interface from the beginning.