From: Vivek Goyal <vgoyal@redhat.com>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: JeffleXu <jefflexu@linux.alibaba.com>,
Stefan Hajnoczi <stefanha@redhat.com>,
linux-fsdevel@vger.kernel.org,
virtualization@lists.linux-foundation.org,
virtio-fs-list <virtio-fs@redhat.com>,
Joseph Qi <joseph.qi@linux.alibaba.com>,
Liu Bo <bo.liu@linux.alibaba.com>
Subject: Re: [PATCH v4 0/8] fuse,virtiofs: support per-file DAX
Date: Wed, 18 Aug 2021 12:58:18 -0400 [thread overview]
Message-ID: <YR08KnP8cO8LjKY7@redhat.com> (raw)
In-Reply-To: <CAJfpegsdX1H_=ZMORA-9YiBGdszG0WVmAjFY2QSZPa0iLUEjXw@mail.gmail.com>
On Wed, Aug 18, 2021 at 07:08:24AM +0200, Miklos Szeredi wrote:
> On Wed, 18 Aug 2021 at 05:40, JeffleXu <jefflexu@linux.alibaba.com> wrote:
>
> > I'm not sure if I fully understand your idea. Then in this case, host
> > daemon only prepares 4KB while guest thinks that the whole DAX window
> > (e.g., 2MB) has been fully mapped. Then when guest really accesses the
> > remained part (2MB - 4KB), page fault is triggered, and now host daemon
> > is responsible for downloading the remained part?
>
> Yes. Mapping an area just means setting up the page tables, it does
> not result in actual data transfer.
But daemon will not get the page fault (its the host kernel which
will handle it). And host kernel does not know that file chunk
needs to be downloaded.
- Either we somehow figure out user fault handling and somehow
qemu/virtiofsd get to handle the page fault then they can
download file.
- Or we download the 2MB chunk at the FUSE_SETUPMAPPING time so
that later kernel fault can handle it.
Am I missing something.
Vivek
next prev parent reply other threads:[~2021-08-18 16:58 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-17 2:22 [PATCH v4 0/8] fuse,virtiofs: support per-file DAX Jeffle Xu
2021-08-17 2:22 ` [PATCH v4 1/8] fuse: add fuse_should_enable_dax() helper Jeffle Xu
2021-08-17 2:22 ` [PATCH v4 2/8] fuse: Make DAX mount option a tri-state Jeffle Xu
2021-08-17 2:22 ` [PATCH v4 3/8] fuse: support per-file DAX Jeffle Xu
2021-08-17 2:22 ` [PATCH v4 4/8] fuse: negotiate if server/client supports " Jeffle Xu
2021-08-17 2:22 ` [PATCH v4 5/8] fuse: enable " Jeffle Xu
2021-08-17 2:22 ` [PATCH v4 6/8] fuse: mark inode DONT_CACHE when per-file DAX indication changes Jeffle Xu
2021-08-17 10:26 ` [Virtio-fs] " Dr. David Alan Gilbert
2021-08-17 13:23 ` JeffleXu
2021-08-17 2:22 ` [PATCH v4 7/8] fuse: support changing per-file DAX flag inside guest Jeffle Xu
2021-08-17 2:22 ` [PATCH v4 8/8] fuse: show '-o dax=inode' option only when FUSE server supports Jeffle Xu
2021-08-17 2:23 ` [virtiofsd PATCH v4 0/4] virtiofsd: support per-file DAX Jeffle Xu
2021-08-17 2:23 ` [virtiofsd PATCH v4 1/4] virtiofsd: add .ioctl() support Jeffle Xu
2021-08-18 17:33 ` Vivek Goyal
2021-08-17 2:23 ` [virtiofsd PATCH v4 2/4] virtiofsd: expand fuse protocol to support per-file DAX Jeffle Xu
2021-08-17 2:23 ` [virtiofsd PATCH v4 3/4] virtiofsd: support per-file DAX negotiation in FUSE_INIT Jeffle Xu
2021-08-17 17:15 ` [Virtio-fs] " Dr. David Alan Gilbert
2021-08-18 5:28 ` JeffleXu
2021-08-19 13:57 ` Dr. David Alan Gilbert
2021-08-18 17:30 ` Vivek Goyal
2021-08-17 2:23 ` [virtiofsd PATCH v4 4/4] virtiofsd: support per-file DAX in FUSE_LOOKUP Jeffle Xu
2021-08-17 19:00 ` [Virtio-fs] " Dr. David Alan Gilbert
2021-08-18 5:46 ` JeffleXu
2021-08-19 13:08 ` Dr. David Alan Gilbert
2021-08-20 5:03 ` JeffleXu
2021-08-24 10:15 ` Greg Kurz
2021-09-08 10:34 ` JeffleXu
2021-08-17 8:06 ` [PATCH v4 0/8] fuse,virtiofs: support per-file DAX Miklos Szeredi
2021-08-17 9:32 ` [Virtio-fs] " Dr. David Alan Gilbert
2021-08-17 10:09 ` Miklos Szeredi
2021-08-17 10:37 ` Dr. David Alan Gilbert
2021-08-17 13:08 ` JeffleXu
2021-08-17 14:11 ` Miklos Szeredi
2021-08-17 15:19 ` Vivek Goyal
2021-08-17 14:54 ` Vivek Goyal
2021-08-18 5:10 ` JeffleXu
2021-08-19 6:14 ` JeffleXu
2021-08-17 12:40 ` Vivek Goyal
2021-09-16 8:21 ` JeffleXu
2021-09-18 3:06 ` JeffleXu
2021-09-19 19:45 ` Vivek Goyal
2021-09-22 8:16 ` JeffleXu
2021-08-17 12:39 ` Vivek Goyal
2021-08-17 13:22 ` JeffleXu
2021-08-17 14:08 ` Miklos Szeredi
2021-08-18 3:39 ` JeffleXu
2021-08-18 5:08 ` Miklos Szeredi
2021-08-18 16:58 ` Vivek Goyal [this message]
2021-09-03 5:30 ` JeffleXu
2021-09-07 14:51 ` Miklos Szeredi
2021-08-17 14:57 ` Vivek Goyal
2021-08-18 5:20 ` JeffleXu
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