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From: Andreas Dilger <adilger@dilger.ca>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
	linux-btrfs@vger.kernel.org, lsf-pc@lists.linux-foundation.org
Subject: Re: [LSF/MM TOPIC] sharing pages between mappings
Date: Wed, 11 Jan 2017 13:35:02 -0700	[thread overview]
Message-ID: <F2092AFE-A2C8-438E-A8AA-4D74509344F5@dilger.ca> (raw)
In-Reply-To: <CAJfpegv9EhT4Y3QjTZBHoMKSiVGtfmTGPhJp_rh3a7=rFCHu5A@mail.gmail.com>

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On Jan 11, 2017, at 3:29 AM, Miklos Szeredi <miklos@szeredi.hu> wrote:
> 
> I know there's work on this for xfs, but could this be done in generic mm code?
> 
> What are the obstacles?  page->mapping and page->index are the obvious ones.
> 
> If that's too difficult is it maybe enough to share mappings between
> files while they are completely identical and clone the mapping when
> necessary?
> 
> All COW filesystems would benefit, as well as layered ones: lots of
> fuse fs, and in some cases overlayfs too.

For layered filesystems it would also be useful to have an API to move
pages between mappings easily.

> Related:  what can DAX do in the presence of cloned block?
> 
> Thanks,
> Miklos
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Cheers, Andreas






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      parent reply	other threads:[~2017-01-11 20:35 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-01-11 10:29 Miklos Szeredi
2017-01-11 11:51 ` [Lsf-pc] " Jan Kara
2017-01-11 14:13   ` Miklos Szeredi
2017-01-17 15:46     ` Jan Kara
2017-01-11 18:05   ` Darrick J. Wong
2017-01-11 20:35 ` Andreas Dilger [this message]

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