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Date:   Mon, 16 Jan 2023 23:25:50 -0800
From:   Christoph Hellwig <hch@infradead.org>
To:     Niklas Cassel <niklas.cassel@wdc.com>
Cc:     Paolo Valente <paolo.valente@linaro.org>,
        Jens Axboe <axboe@kernel.dk>, Hannes Reinecke <hare@suse.de>,
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Subject: Re: [PATCH v2 07/18] block: introduce duration-limits priority class
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On Thu, Jan 12, 2023 at 03:03:56PM +0100, Niklas Cassel wrote:
> From: Damien Le Moal <damien.lemoal@opensource.wdc.com>
> 
> Introduce the IOPRIO_CLASS_DL priority class to indicate that IOs should
> be executed using duration-limits targets. The duration target to apply
> to a command is indicated using the priority level. Up to 8 levels are
> supported, with level 0 indiating "no limit".
> 
> This priority class has effect only if the target device supports the
> command duration limits feature and this feature is enabled by the user.
> In BFQ and mq-deadline, all requests with this new priority class are
> handled using the highest priority class RT and priority level 0.

Hmm, does it make sense to force a high priority?  Can't applications
use CDL to also fore a lower priority?