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Date:   Wed, 17 May 2023 12:13:04 -0600
From:   Keith Busch <kbusch@kernel.org>
To:     Ming Lei <ming.lei@redhat.com>
Cc:     Bart Van Assche <bvanassche@acm.org>, Jens Axboe <axboe@kernel.dk>,
        linux-block@vger.kernel.org, Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH V2 2/2] blk-mq: make sure elevator callbacks aren't
 called for passthrough request
Message-ID: <ZGUZMATdnt8hFM+A@kbusch-mbp>
References: <20230515144601.52811-1-ming.lei@redhat.com>
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On Wed, May 17, 2023 at 11:26:32AM +0800, Ming Lei wrote:
> On Tue, May 16, 2023 at 08:47:46AM -0600, Keith Busch wrote:
> 
> > And the passthrough case is special with users of that interface taking
> > on a greater responsibility and generally want the kernel out of the
> > way. I don't think anyone would purposefully run a tag intense workload
> > through that engine at the same time as using a generic one with the
> > scheduler. It definitely should still work, but it doesn't need to be
> > fair, right?
> 
> I guess it may work, but question is that what we can get from this kind
> of big change? And I think this approach may be one following work if it is
> proved as useful.

I'm just trying to remove any need for side channels to bypass block
layer functionality, like this one:

  http://lists.infradead.org/pipermail/linux-nvme/2023-April/039522.html