From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io0-f199.google.com (mail-io0-f199.google.com [209.85.223.199]) by kanga.kvack.org (Postfix) with ESMTP id 912756B0033 for ; Wed, 11 Jan 2017 15:35:13 -0500 (EST) Received: by mail-io0-f199.google.com with SMTP id v96so3648896ioi.5 for ; Wed, 11 Jan 2017 12:35:13 -0800 (PST) Received: from mail-it0-x241.google.com (mail-it0-x241.google.com. [2607:f8b0:4001:c0b::241]) by mx.google.com with ESMTPS id 184si6071468iox.230.2017.01.11.12.35.12 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 11 Jan 2017 12:35:12 -0800 (PST) Received: by mail-it0-x241.google.com with SMTP id o185so345002itb.1 for ; Wed, 11 Jan 2017 12:35:12 -0800 (PST) Subject: Re: [LSF/MM TOPIC] sharing pages between mappings Mime-Version: 1.0 (Mac OS X Mail 9.3 \(3124\)) Content-Type: multipart/signed; boundary="Apple-Mail=_24F3C8FA-2453-4243-89D1-AB7658AA1EF6"; protocol="application/pgp-signature"; micalg=pgp-sha256 From: Andreas Dilger In-Reply-To: Date: Wed, 11 Jan 2017 13:35:02 -0700 Message-Id: References: Sender: owner-linux-mm@kvack.org List-ID: To: Miklos Szeredi Cc: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-btrfs@vger.kernel.org, lsf-pc@lists.linux-foundation.org --Apple-Mail=_24F3C8FA-2453-4243-89D1-AB7658AA1EF6 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii On Jan 11, 2017, at 3:29 AM, Miklos Szeredi wrote: >=20 > I know there's work on this for xfs, but could this be done in generic = mm code? >=20 > What are the obstacles? page->mapping and page->index are the obvious = ones. >=20 > 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? >=20 > 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? >=20 > Thanks, > Miklos > -- > To unsubscribe from this list: send the line "unsubscribe = linux-fsdevel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html Cheers, Andreas --Apple-Mail=_24F3C8FA-2453-4243-89D1-AB7658AA1EF6 Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename=signature.asc Content-Type: application/pgp-signature; name=signature.asc Content-Description: Message signed with OpenPGP using GPGMail -----BEGIN PGP SIGNATURE----- Comment: GPGTools - http://gpgtools.org iQIVAwUBWHaW+nKl2rkXzB/gAQjc7w//a18EVoNWjZcRbvDR7W+hTNBjQcM4gkpZ 8sh3xLTjApmxTp6CLpp1EdEGqHemyvuPlweFR/Yc5kKnqhHV7pP2PkRuUf42M2bd KGZ6DSD1z+hjdLJ9/gAotWEWUOlU9ou4UyEeHsRrv+upZv65/DrXsvkLfZr9Ych4 yDCtPWI1AT47p3S7huGTAnsK+XJLfGsDVfwEuTp7QbJ1k/NsrVDNBAoV6ikhjKnr a9KfMCKrRnvb6HRVy/PaOZfUWF7JhRRSCxiTBxBSbwaQRXIjRQ0H/J5EaRalruQ9 Y5dPsL80pe1tM9cDj1nyAFfgqHWJOKgdTN9cS8wH3/2OUwB3gyZyqrkMgqsRLW4q wztLpwO65Z+rdmp4k13EB0UuxNHg2wh3hX991aD+wztahN/dhfxeqAE7sCttO9tC S+6rj/9twfyUdOjpLxu31chowUgcNKMZespczTMLz0yIe6NFS7WI1vAfNFxtmhvn 1D6f51F4bpEAtih9PzoxL3rN+qmENW+TO6LFpgTYhSw5iXy8QmfyS4Iz6DGfec+8 NpuWZ8mp+Ak+NVTDH450T4yblKq9/3MCIXlPnHeethrYYwZrYvN5Q28Znfc5zNlQ KXOjP9pzgwOzjq1Rp0Uv1MWv4pbvTFgTA4Zimejx64mGU3PTRX7Noe4UdCvdV5mB OA/ov38SKWE= =EwIV -----END PGP SIGNATURE----- --Apple-Mail=_24F3C8FA-2453-4243-89D1-AB7658AA1EF6-- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org