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Date:   Fri, 22 Jul 2022 09:08:02 -0700
From:   Christoph Hellwig <hch@infradead.org>
To:     Liu Song <liusong@linux.alibaba.com>
Cc:     Christoph Hellwig <hch@infradead.org>, axboe@kernel.dk,
        linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] blk-mq: avoid potential infinite loop in
 __blk_mq_alloc_request
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On Fri, Jul 22, 2022 at 04:15:49PM +0800, Liu Song wrote:
> It is a reasonable approach to prevent abnormal alloc from going down,
> but this is a very rare exception after all, and above modification is
> checked
> every alloc request, which seems to be a bit excessive overhead.

Every allocation of a passthrough requests.  Which isn't really the
normal fast path.