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Date: Fri, 11 Aug 2017 12:46:15 +0200
From: Christoph Hellwig <hch@lst.de>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>, Minchan Kim <minchan@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
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        kernel-team <kernel-team@lge.com>
Subject: Re: [PATCH v1 2/6] fs: use on-stack-bio if backing device has
        BDI_CAP_SYNC capability
Message-ID: <20170811104615.GA14397@lst.de>
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On Wed, Aug 09, 2017 at 08:06:24PM -0700, Dan Williams wrote:
> I like it, but do you think we should switch to sbvec[<constant>] to
> preclude pathological cases where nr_pages is large?

Yes, please.

Then I'd like to see that the on-stack bio even matters for
mpage_readpage / mpage_writepage.  Compared to all the buffer head
overhead the bio allocation should not actually matter in practice.