From: Matthew Wilcox <willy@infradead.org>
To: Amir Goldstein <amir73il@gmail.com>
Cc: John Groves <john@jagalactic.com>, John Groves <John@groves.net>,
Miklos Szeredi <miklos@szeredi.hu>,
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Subject: Re: [PATCH V12 00/12] famfs: the Fabric-Attached Memory File System (standalone)
Date: Thu, 6 Aug 2026 06:19:49 +0100 [thread overview]
Message-ID: <anQZdSsJSyoqJkCo@casper.infradead.org> (raw)
In-Reply-To: <CAOQ4uxhpkP7FsjaqqVO2aDSKCJ9yc3WKms6dncqnDuwGxqthng@mail.gmail.com>
On Mon, Aug 03, 2026 at 10:52:19AM +0200, Amir Goldstein wrote:
> > The most important thing to know about famfs is that it CANNOT be used as a
> > general purpose file system. It is for enabling file-based byte-level access
> > (including direct mmap) to very large (e.g. 100TB) shared/disaggregated
> > memory appliances - which have become available during this long process,
> > and which are in need of Linux support.
> >
> > So famfs cannot be used by anybody who doesn't know why they need it; Making
> > famfs standalone means it can't affect users who don't use it. And my super-
> > mega-corp employer (Micron), as well as other memory companies, need it.
> > We do not intend to abandon it, but imagine if we did: fs/famfs/ should be
> > removed if the memory companies can't be bothered to maintain it.
>
> It does not work this way.
> When vfs maintainers accept standalone famfs they accept the burden of
> maintaining it whenever vfs internal APIs change even if the filesystem was
> abandoned by the mega-corps.
> That is the code of the push back for adding new filesystems.
> Removing the fs and breaking deployed systems is not an option for the vfs
> maintainers.
Sure it is. We removed EFS just last month, because we decided that it
wasn't worth keeping any more. Just like we removed Itanium architecture
support (and a number of other architectures before that). We've removed
other filesystems in the past (xiafs, ext, surely a few others).
Yes, there are burdens on others by accepting this filesystem -- but if
it's a standalone VFS filesystem, those are felt by those who work on
the VFS. If it's part of FUSE, then it's felt by those who work on FUSE.
And we've already determined that those who work on FUSE are even more
overburdened than those who work on the VFS.
famfs does not seem to be a natural fit for FUSE. It has needs unlike any
other Linux filesystem, and quite possibly unlike any other filesystem
that is to come. Rearchitecting FUSE to make famfs fit seems like a
very dodgy proposition to me.
next prev parent reply other threads:[~2026-08-06 5:20 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20260803022730.75731-1-john@jagalactic.com>
2026-08-03 2:27 ` [PATCH V12 00/12] famfs: the Fabric-Attached Memory File System (standalone) John Groves
2026-08-03 2:28 ` [PATCH V12 01/12] dax: replace exported dax_dev_get() with non-allocating dax_dev_find() John Groves
2026-08-03 2:43 ` sashiko-bot
2026-08-03 19:13 ` Alison Schofield
2026-08-05 20:21 ` John Groves
2026-08-03 2:28 ` [PATCH V12 02/12] famfs: Module operations, fs_context, and mount John Groves
2026-08-03 2:49 ` sashiko-bot
2026-08-06 4:37 ` Darrick J. Wong
2026-08-06 13:22 ` John Groves
2026-08-03 2:28 ` [PATCH V12 03/12] famfs: Add daxdev table and dax notify_failure support John Groves
2026-08-03 2:45 ` sashiko-bot
2026-08-06 5:05 ` Darrick J. Wong
2026-08-06 13:36 ` John Groves
2026-08-03 2:28 ` [PATCH V12 04/12] famfs: Introduce inode_operations and super_operations John Groves
2026-08-03 2:42 ` sashiko-bot
2026-08-06 5:12 ` Darrick J. Wong
2026-08-06 16:31 ` John Groves
2026-08-03 2:29 ` [PATCH V12 05/12] famfs: Introduce file_operations read/write John Groves
2026-08-03 2:42 ` sashiko-bot
2026-08-06 5:14 ` Darrick J. Wong
2026-08-06 20:03 ` John Groves
2026-08-03 2:29 ` [PATCH V12 06/12] famfs: Introduce mmap and VM fault handling John Groves
2026-08-03 2:46 ` sashiko-bot
2026-08-06 5:16 ` Darrick J. Wong
2026-08-06 20:40 ` John Groves
2026-08-03 2:29 ` [PATCH V12 07/12] famfs: MAP_CREATE ioctl and fmap ingest (ABI 44) John Groves
2026-08-03 2:42 ` sashiko-bot
2026-08-06 5:24 ` Darrick J. Wong
2026-08-06 20:53 ` John Groves
2026-08-03 2:29 ` [PATCH V12 08/12] famfs: iomap_begin and file-to-dax offset resolution John Groves
2026-08-03 2:44 ` sashiko-bot
2026-08-06 5:28 ` Darrick J. Wong
2026-08-06 22:14 ` John Groves
2026-08-03 2:29 ` [PATCH V12 09/12] famfs: Register secondary daxdevs by path (FAMFSIOC_DAXDEV_OPEN) John Groves
2026-08-03 2:42 ` sashiko-bot
2026-08-06 5:29 ` Darrick J. Wong
2026-08-06 22:22 ` John Groves
2026-08-03 2:29 ` [PATCH V12 10/12] famfs: Add runtime operation-permission (opts) framework John Groves
2026-08-03 2:42 ` sashiko-bot
2026-08-06 5:31 ` Darrick J. Wong
2026-08-06 22:30 ` John Groves
2026-08-03 2:30 ` [PATCH V12 11/12] famfs: Report device capacity via statfs so df works John Groves
2026-08-03 2:58 ` sashiko-bot
2026-08-06 5:33 ` Darrick J. Wong
2026-08-03 2:30 ` [PATCH V12 12/12] famfs: Add documentation John Groves
2026-08-06 5:38 ` Darrick J. Wong
2026-08-03 8:52 ` [PATCH V12 00/12] famfs: the Fabric-Attached Memory File System (standalone) Amir Goldstein
2026-08-06 5:19 ` Matthew Wilcox [this message]
2026-08-06 5:34 ` Darrick J. Wong
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