From: Christoph Hellwig <hch@infradead.org>
To: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dan Williams <djbw@kernel.org>, Gregory Price <gourry@gourry.net>,
Joanne Koong <joannelkoong@gmail.com>,
John Groves <John@groves.net>, Miklos Szeredi <miklos@szeredi.hu>,
Bernd Schubert <bernd@bsbernd.com>,
John Groves <john@jagalactic.com>,
Dan J Williams <dan.j.williams@intel.com>,
Bernd Schubert <bschubert@ddn.com>,
Alison Schofield <alison.schofield@intel.com>,
John Groves <jgroves@micron.com>,
Jonathan Corbet <corbet@lwn.net>,
Shuah Khan <skhan@linuxfoundation.org>,
Vishal Verma <vishal.l.verma@intel.com>,
Dave Jiang <dave.jiang@intel.com>,
Matthew Wilcox <willy@infradead.org>, Jan Kara <jack@suse.cz>,
Alexander Viro <viro@zeniv.linux.org.uk>,
David Hildenbrand <david@kernel.org>,
Christian Brauner <brauner@kernel.org>,
Randy Dunlap <rdunlap@infradead.org>,
Jeff Layton <jlayton@kernel.org>,
Amir Goldstein <amir73il@gmail.com>,
Jonathan Cameron <Jonathan.Cameron@huawei.com>,
Stefan Hajnoczi <shajnocz@redhat.com>,
Josef Bacik <josef@toxicpanda.com>,
Bagas Sanjaya <bagasdotme@gmail.com>,
Chen Linxuan <chenlinxuan@uniontech.com>,
James Morse <james.morse@arm.com>, Fuad Tabba <tabba@google.com>,
Sean Christopherson <seanjc@google.com>,
Shivank Garg <shivankg@amd.com>,
Ackerley Tng <ackerleytng@google.com>,
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Ajay Joshi <ajayjoshi@micron.com>,
"venkataravis@micron.com" <venkataravis@micron.com>,
"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"nvdimm@lists.linux.dev" <nvdimm@lists.linux.dev>,
"linux-cxl@vger.kernel.org" <linux-cxl@vger.kernel.org>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>
Subject: Re: [PATCH V10 00/10] famfs: port into fuse
Date: Fri, 17 Apr 2026 01:13:36 -0700 [thread overview]
Message-ID: <aeHrsIGagdmZJ1Fw@infradead.org> (raw)
In-Reply-To: <20260416224331.GD114184@frogsfrogsfrogs>
On Thu, Apr 16, 2026 at 03:43:31PM -0700, Darrick J. Wong wrote:
> ...the memory interleaving is a rather interesting quality of famfs.
> There's no good way to express a formulaic meta-mapping in traditional
> iomap parlance, and famfs needs that to interleave across memory
> controllers/dimm boxen/whatever. Throwing individual iomaps at the
> kernel is a very inefficient way to do that. So I don't think there's a
> good reason to get rid of GET_FMAP at this time...
Why no? We can triviall make an iomap point to multiple backing
devices and throw in a stride/offset. That would make btrfs
striping (and non-degraded parity RAID reads) a lot more efficient.
> ...however the strongest case (IMO) would be if (having merged famfs) we
> then merge fuse-iomap after famfs. Then we extend the existing
> fuse-iomap-bpf prototype to allow per-mount and per-inode iomap bpf ops.
> That enables us to analyze thoroughly the performance characteristics of:
Don't go there. I think that you two are comining up with two
interfaces for roughly the same thing is a pretty clear indicator
that this needs to be fully hashed out as a single interface first,
and any kind of preliminary merging is just going to create problems.
next prev parent reply other threads:[~2026-04-17 8:13 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20260331123702.35052-1-john@jagalactic.com>
2026-03-31 12:37 ` [PATCH V10 00/10] famfs: port into fuse John Groves
2026-03-31 12:38 ` [PATCH V10 01/10] famfs_fuse: Update macro s/FUSE_IS_DAX/FUSE_IS_VIRTIO_DAX/ John Groves
2026-03-31 12:38 ` [PATCH V10 02/10] famfs_fuse: Basic fuse kernel ABI enablement for famfs John Groves
2026-03-31 12:38 ` [PATCH V10 03/10] famfs_fuse: Plumb the GET_FMAP message/response John Groves
2026-03-31 12:38 ` [PATCH V10 04/10] famfs_fuse: Create files with famfs fmaps John Groves
2026-03-31 12:38 ` [PATCH V10 05/10] famfs_fuse: GET_DAXDEV message and daxdev_table John Groves
2026-03-31 12:39 ` [PATCH V10 06/10] famfs_fuse: Plumb dax iomap and fuse read/write/mmap John Groves
2026-03-31 12:39 ` [PATCH V10 07/10] famfs_fuse: Add holder_operations for dax notify_failure() John Groves
2026-03-31 12:39 ` [PATCH V10 08/10] famfs_fuse: Add DAX address_space_operations with noop_dirty_folio John Groves
2026-03-31 12:39 ` [PATCH V10 09/10] famfs_fuse: Add famfs fmap metadata documentation John Groves
2026-03-31 12:39 ` [PATCH V10 10/10] famfs_fuse: Add documentation John Groves
2026-04-01 15:15 ` [PATCH V10 00/10] famfs: port into fuse John Groves
2026-04-06 17:43 ` Joanne Koong
2026-04-10 14:46 ` John Groves
2026-04-10 15:24 ` Bernd Schubert
2026-04-10 18:38 ` John Groves
2026-04-10 19:44 ` Joanne Koong
2026-04-14 13:19 ` Miklos Szeredi
2026-04-14 13:41 ` John Groves
2026-04-14 14:18 ` Miklos Szeredi
2026-04-14 15:23 ` John Groves
2026-04-14 18:57 ` Darrick J. Wong
2026-04-14 22:13 ` Joanne Koong
2026-04-14 23:36 ` Darrick J. Wong
2026-04-15 0:10 ` John Groves
2026-04-16 15:56 ` Joanne Koong
2026-04-16 20:14 ` Gregory Price
2026-04-16 20:53 ` Dan Williams
2026-04-16 22:43 ` Darrick J. Wong
2026-04-17 0:44 ` Joanne Koong
2026-04-17 5:40 ` Darrick J. Wong
2026-04-17 8:17 ` Christoph Hellwig
2026-04-17 15:58 ` Darrick J. Wong
2026-04-17 8:13 ` Christoph Hellwig [this message]
2026-04-17 13:30 ` Gregory Price
2026-04-17 1:24 ` Joanne Koong
2026-04-17 6:46 ` Gregory Price
2026-04-17 9:06 ` Amir Goldstein
2026-04-24 13:33 ` Christoph Hellwig
2026-04-24 14:35 ` Amir Goldstein
2026-04-14 22:20 ` Gregory Price
2026-04-15 8:16 ` David Hildenbrand (Arm)
2026-04-15 13:34 ` Gregory Price
2026-04-15 14:04 ` Miklos Szeredi
2026-04-15 15:10 ` Matthew Wilcox
2026-04-15 15:28 ` Darrick J. Wong
2026-04-15 15:32 ` Gregory Price
2026-04-15 17:12 ` Joanne Koong
2026-04-15 19:40 ` Gregory Price
2026-04-19 20:36 ` John Groves
2026-04-20 0:27 ` Gregory Price
2026-04-21 3:12 ` Joanne Koong
2026-04-21 14:30 ` Gregory Price
2026-04-21 18:59 ` Joanne Koong
2026-04-21 22:13 ` Gregory Price
2026-04-14 23:53 ` John Groves
2026-04-15 0:15 ` Darrick J. Wong
2026-04-15 8:57 ` Miklos Szeredi
2026-04-17 8:04 ` Christoph Hellwig
2026-04-17 19:35 ` Joanne Koong
2026-04-21 6:59 ` Christian Brauner
2026-05-04 15:08 ` Bernd Schubert
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