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From: Christoph Hellwig <hch@infradead.org>
To: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: linux-kernel@vger.kernel.org, linux-block@vger.kernel.org,
	dm-devel@redhat.com, linux-raid@vger.kernel.org,
	Jens Axboe <axboe@kernel.dk>,
	Christoph Hellwig <hch@infradead.org>
Subject: Re: [PATCH RFC 1/3] block: add flag 'nowait_requests' into queue limits
Date: Tue, 2 Jun 2020 21:58:22 -0700	[thread overview]
Message-ID: <20200603045822.GA17137@infradead.org> (raw)
In-Reply-To: <159101502963.180989.6228080995222059011.stgit@buzz>

On Mon, Jun 01, 2020 at 03:37:09PM +0300, Konstantin Khlebnikov wrote:
> Add flag for marking bio-based queues which support REQ_NOWAIT.
> Set for all request based (mq) devices.
> 
> Stacking device should set it after blk_set_stacking_limits() if method
> make_request() itself doesn't delay requests or handles REQ_NOWAIT.

I don't think this belongs into the queue limits.  For example a
stacking driver that always defers requests to a workqueue can support
REQ_NOWAIT entirely independent of the underlying devices.  I think
this just needs to be a simple queue flag.

  reply	other threads:[~2020-06-03  4:58 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-01 12:37 [PATCH RFC 0/3] block: allow REQ_NOWAIT to some bio-based/stacked devices Konstantin Khlebnikov
2020-06-01 12:37 ` [PATCH RFC 1/3] block: add flag 'nowait_requests' into queue limits Konstantin Khlebnikov
2020-06-03  4:58   ` Christoph Hellwig [this message]
2020-06-03  8:24     ` Konstantin Khlebnikov
2020-06-01 12:37 ` [PATCH RFC 2/3] md/raid0: enable REQ_NOWAIT Konstantin Khlebnikov
2020-06-01 12:37 ` [PATCH RFC 3/3] dm: add support for REQ_NOWAIT and enable for target dm-linear Konstantin Khlebnikov

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