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Mon, 13 Jan 2025 11:21:32 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id bJ1hFzz3hGcEewAAD6G6ig (envelope-from ); Mon, 13 Jan 2025 11:21:32 +0000 Received: by quack3.suse.cz (Postfix, from userid 1000) id 1BCEBA08E2; Mon, 13 Jan 2025 12:21:32 +0100 (CET) Date: Mon, 13 Jan 2025 12:21:32 +0100 From: Jan Kara To: Lorenzo Stoakes Cc: Jan Kara , lsf-pc@lists.linux-foundation.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org Subject: Re: [Lsf-pc] [LSF/MM/BPF TOPIC] The future of anon_vma Message-ID: References: <29ad6455-cabb-4ae9-b2d6-db1c09c0009a@lucifer.local> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <29ad6455-cabb-4ae9-b2d6-db1c09c0009a@lucifer.local> X-Rspamd-Queue-Id: EC99A1C0015 X-Rspamd-Server: rspam12 X-Stat-Signature: 63r6pohx1uq6195868pngh6mayaw8oko X-Rspam-User: X-HE-Tag: 1736767293-149814 X-HE-Meta: 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 i08lo93s pha1M0scMb+F3+tlgDz/6xUQEI+xho5xsPHnekvCsnZb1ucBPK01lPWZaxDqDEHnAkCZPJrb7ITqb52WdpFw8+YQrYdrF9iK/XimBv2z+AtKkpfPYwBRamT0XfvMwoQxqBaoDmSW/algq4z0Mi0dMj1xL32x0YNlv/P9odwRZqrBGubo+8Io57BVxAw1NPHNvIvVchcV7+Rv4zqsfvlRwiK2vnV0VnTY5c7QsMXLblP6rblTyD2hXvJHuyRQQV1cNGB30DHHfbn77NT6tLDA78vMOw/8PVRBrY4YyO63VDZ/QFc/PNhWI0Eu2pvRReE3uWMrz01yv7JeDjCoD9bGgHeliQCJ+35/2UU81Yd2FZp/1/7oueTWcGYVPHM8LxmFiCHRg X-Bogosity: Ham, tests=bogofilter, spamicity=0.021695, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu 09-01-25 12:33:52, Lorenzo Stoakes wrote: > On Thu, Jan 09, 2025 at 11:21:02AM +0100, Jan Kara wrote: > > On Wed 08-01-25 22:23:16, Lorenzo Stoakes via Lsf-pc wrote: > > > A future where we unify anonymous and file-backed memory mappings would be > > > one in which a reflinks were implemented at a general level rather than, as > > > they are now, implemented individually within file systems. > > > > > > I'd like to discuss how feasible doing so might be, whether this is a sane > > > line of thought at all, and how a roadmap for working towards the > > > elimination of anon_vma as it stands might look. > > > > As you can imagine this has been discussed in the past and some folks are > > very interested in saving page cache memory for some heavily reflinked > > container setups or for various FUSE filesystems. So if someone manages to > > come up with a feasible design, the usecases are there. I think reading > > e.g. [1] and comments below it is a good preparation for the session to get > > some idea what challenges are there :). > > Oh I certainly imagined that it had :) Perhaps you are volunteering to > assist me from an fs point of view on this Jan? ;) Sure, I'll be happy to provide you with a FS point of view :) Honza -- Jan Kara SUSE Labs, CR