From mboxrd@z Thu Jan  1 00:00:00 1970
From: Christoph Hellwig <hch@infradead.org>
Subject: Re: allowed pages in the block later, was Re: [PATCH] ext3: avoid sending down non-refcounted pages
Date: Mon, 12 Dec 2005 17:27:02 +0000
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References: <20051208180900T.fujita.tomonori@lab.ntt.co.jp> <20051208101833.GM14509@schatzie.adilger.int> <20051208134239.GA13376@infradead.org> <84144f020512080558tb9bb6bbjf91e72ad3d9ccaa6@mail.gmail.com>
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Cc: Christoph Hellwig <hch@infradead.org>,
	FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>,
	michaelc@cs.wisc.edu, linux-fsdevel@vger.kernel.org,
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To: Pekka Enberg <penberg@cs.helsinki.fi>
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On Thu, Dec 08, 2005 at 03:58:46PM +0200, Pekka Enberg wrote:
> Hi Christoph,
> 
> On 12/8/05, Christoph Hellwig <hch@infradead.org> wrote:
> > One way to work around that would be to detect kmalloced pages and use
> > a slowpath for that.  The major issues with that is that we don't have a
> > reliable way to detect if a given struct page comes from the slab allocator
> > or not.
> 
> Why doesn't PageSlab work for you?

When I looked last time it was a noop without slab debugging enabled,
but that's not the case in current mainline anymore.
If the VM people agree with that usage we could at least use it to fall
back to slow-path.  Even better would be to require normal pages, though.


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