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From: Miklos Szeredi <miklos@szeredi.hu>
To: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Jeffle Xu <jefflexu@linux.alibaba.com>,
	virtualization@lists.linux-foundation.org,
	virtio-fs-list <virtio-fs@redhat.com>,
	Joseph Qi <joseph.qi@linux.alibaba.com>,
	linux-fsdevel@vger.kernel.org, Vivek Goyal <vgoyal@redhat.com>
Subject: Re: [Virtio-fs] [PATCH v4 0/8] fuse,virtiofs: support per-file DAX
Date: Tue, 17 Aug 2021 12:09:40 +0200	[thread overview]
Message-ID: <CAJfpegvM+S5Xru3Yfc88C64mecvco=f99y-TajQBDfkLD-S8zQ@mail.gmail.com> (raw)
In-Reply-To: <YRuCHvhICtTzMK04@work-vm>

On Tue, 17 Aug 2021 at 11:32, Dr. David Alan Gilbert
<dgilbert@redhat.com> wrote:
>
> * Miklos Szeredi (miklos@szeredi.hu) wrote:
> > On Tue, 17 Aug 2021 at 04:22, Jeffle Xu <jefflexu@linux.alibaba.com> wrote:
> > >
> > > This patchset adds support of per-file DAX for virtiofs, which is
> > > inspired by Ira Weiny's work on ext4[1] and xfs[2].
> >
> > Can you please explain the background of this change in detail?
> >
> > Why would an admin want to enable DAX for a particular virtiofs file
> > and not for others?
>
> Where we're contending on virtiofs dax cache size it makes a lot of
> sense; it's quite expensive for us to map something into the cache
> (especially if we push something else out), so selectively DAXing files
> that are expected to be hot could help reduce cache churn.

If this is a performance issue, it should be fixed in a way that
doesn't require hand tuning like you suggest, I think.

I'm not sure what the  ext4/xfs case for per-file DAX is.  Maybe that
can help understand the virtiofs case as well.

Thanks,
Miklos

WARNING: multiple messages have this Message-ID (diff)
From: Miklos Szeredi <miklos@szeredi.hu>
To: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Joseph Qi <joseph.qi@linux.alibaba.com>,
	virtualization@lists.linux-foundation.org,
	virtio-fs-list <virtio-fs@redhat.com>,
	linux-fsdevel@vger.kernel.org,
	Jeffle Xu <jefflexu@linux.alibaba.com>,
	Vivek Goyal <vgoyal@redhat.com>
Subject: Re: [Virtio-fs] [PATCH v4 0/8] fuse,virtiofs: support per-file DAX
Date: Tue, 17 Aug 2021 12:09:40 +0200	[thread overview]
Message-ID: <CAJfpegvM+S5Xru3Yfc88C64mecvco=f99y-TajQBDfkLD-S8zQ@mail.gmail.com> (raw)
In-Reply-To: <YRuCHvhICtTzMK04@work-vm>

On Tue, 17 Aug 2021 at 11:32, Dr. David Alan Gilbert
<dgilbert@redhat.com> wrote:
>
> * Miklos Szeredi (miklos@szeredi.hu) wrote:
> > On Tue, 17 Aug 2021 at 04:22, Jeffle Xu <jefflexu@linux.alibaba.com> wrote:
> > >
> > > This patchset adds support of per-file DAX for virtiofs, which is
> > > inspired by Ira Weiny's work on ext4[1] and xfs[2].
> >
> > Can you please explain the background of this change in detail?
> >
> > Why would an admin want to enable DAX for a particular virtiofs file
> > and not for others?
>
> Where we're contending on virtiofs dax cache size it makes a lot of
> sense; it's quite expensive for us to map something into the cache
> (especially if we push something else out), so selectively DAXing files
> that are expected to be hot could help reduce cache churn.

If this is a performance issue, it should be fixed in a way that
doesn't require hand tuning like you suggest, I think.

I'm not sure what the  ext4/xfs case for per-file DAX is.  Maybe that
can help understand the virtiofs case as well.

Thanks,
Miklos


  reply	other threads:[~2021-08-17 10:09 UTC|newest]

Thread overview: 151+ 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 ` [Virtio-fs] " Jeffle Xu
2021-08-17  2:22 ` 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   ` [Virtio-fs] " Jeffle Xu
2021-08-17  2:22   ` 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   ` [Virtio-fs] " Jeffle Xu
2021-08-17  2:22   ` Jeffle Xu
2021-08-17  2:22 ` [PATCH v4 3/8] fuse: support per-file DAX Jeffle Xu
2021-08-17  2:22   ` [Virtio-fs] " Jeffle Xu
2021-08-17  2:22   ` Jeffle Xu
2021-08-17  2:22 ` [PATCH v4 4/8] fuse: negotiate if server/client supports " Jeffle Xu
2021-08-17  2:22   ` [Virtio-fs] " Jeffle Xu
2021-08-17  2:22   ` Jeffle Xu
2021-08-17  2:22 ` [PATCH v4 5/8] fuse: enable " Jeffle Xu
2021-08-17  2:22   ` [Virtio-fs] " Jeffle Xu
2021-08-17  2:22   ` 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  2:22   ` [Virtio-fs] " Jeffle Xu
2021-08-17  2:22   ` Jeffle Xu
2021-08-17 10:26   ` [Virtio-fs] " Dr. David Alan Gilbert
2021-08-17 10:26     ` Dr. David Alan Gilbert
2021-08-17 10:26     ` Dr. David Alan Gilbert
2021-08-17 13:23     ` JeffleXu
2021-08-17 13:23       ` JeffleXu
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   ` [Virtio-fs] " Jeffle Xu
2021-08-17  2:22   ` 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  2:22   ` [Virtio-fs] " Jeffle Xu
2021-08-17  2:22   ` Jeffle Xu
2021-08-17  2:23 ` [virtiofsd PATCH v4 0/4] virtiofsd: support per-file DAX Jeffle Xu
2021-08-17  2:23   ` [Virtio-fs] " Jeffle Xu
2021-08-17  2:23   ` Jeffle Xu
2021-08-17  2:23   ` [virtiofsd PATCH v4 1/4] virtiofsd: add .ioctl() support Jeffle Xu
2021-08-17  2:23     ` [Virtio-fs] " Jeffle Xu
2021-08-17  2:23     ` Jeffle Xu
2021-08-18 17:33     ` Vivek Goyal
2021-08-18 17:33       ` [Virtio-fs] " Vivek Goyal
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     ` [Virtio-fs] " Jeffle Xu
2021-08-17  2:23     ` 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  2:23     ` [Virtio-fs] " Jeffle Xu
2021-08-17  2:23     ` Jeffle Xu
2021-08-17 17:15     ` [Virtio-fs] " Dr. David Alan Gilbert
2021-08-17 17:15       ` Dr. David Alan Gilbert
2021-08-17 17:15       ` Dr. David Alan Gilbert
2021-08-18  5:28       ` JeffleXu
2021-08-18  5:28         ` JeffleXu
2021-08-18  5:28         ` JeffleXu
2021-08-19 13:57         ` Dr. David Alan Gilbert
2021-08-19 13:57           ` Dr. David Alan Gilbert
2021-08-19 13:57           ` Dr. David Alan Gilbert
2021-08-18 17:30       ` Vivek Goyal
2021-08-18 17:30         ` Vivek Goyal
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  2:23     ` [Virtio-fs] " Jeffle Xu
2021-08-17  2:23     ` Jeffle Xu
2021-08-17 19:00     ` [Virtio-fs] " Dr. David Alan Gilbert
2021-08-17 19:00       ` Dr. David Alan Gilbert
2021-08-17 19:00       ` Dr. David Alan Gilbert
2021-08-18  5:46       ` JeffleXu
2021-08-18  5:46         ` JeffleXu
2021-08-18  5:46         ` JeffleXu
2021-08-19 13:08         ` Dr. David Alan Gilbert
2021-08-19 13:08           ` Dr. David Alan Gilbert
2021-08-19 13:08           ` Dr. David Alan Gilbert
2021-08-20  5:03           ` JeffleXu
2021-08-20  5:03             ` JeffleXu
2021-08-20  5:03             ` JeffleXu
2021-08-24 10:15             ` Greg Kurz
2021-08-24 10:15               ` Greg Kurz
2021-08-24 10:15               ` Greg Kurz
2021-09-08 10:34               ` JeffleXu
2021-09-08 10:34                 ` JeffleXu
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  8:06   ` [Virtio-fs] " Miklos Szeredi
2021-08-17  9:32   ` Dr. David Alan Gilbert
2021-08-17  9:32     ` Dr. David Alan Gilbert
2021-08-17  9:32     ` Dr. David Alan Gilbert
2021-08-17 10:09     ` Miklos Szeredi [this message]
2021-08-17 10:09       ` Miklos Szeredi
2021-08-17 10:37       ` Dr. David Alan Gilbert
2021-08-17 10:37         ` Dr. David Alan Gilbert
2021-08-17 10:37         ` Dr. David Alan Gilbert
2021-08-17 13:08       ` JeffleXu
2021-08-17 13:08         ` JeffleXu
2021-08-17 13:08         ` JeffleXu
2021-08-17 14:11         ` Miklos Szeredi
2021-08-17 14:11           ` Miklos Szeredi
2021-08-17 15:19           ` Vivek Goyal
2021-08-17 15:19             ` Vivek Goyal
2021-08-17 15:19             ` Vivek Goyal
2021-08-17 14:54         ` Vivek Goyal
2021-08-17 14:54           ` Vivek Goyal
2021-08-17 14:54           ` Vivek Goyal
2021-08-18  5:10           ` JeffleXu
2021-08-18  5:10             ` JeffleXu
2021-08-18  5:10             ` JeffleXu
2021-08-19  6:14           ` JeffleXu
2021-08-19  6:14             ` JeffleXu
2021-08-19  6:14             ` JeffleXu
2021-08-17 12:40     ` Vivek Goyal
2021-08-17 12:40       ` Vivek Goyal
2021-08-17 12:40       ` Vivek Goyal
2021-09-16  8:21       ` JeffleXu
2021-09-16  8:21         ` JeffleXu
2021-09-16  8:21         ` JeffleXu
2021-09-18  3:06         ` JeffleXu
2021-09-18  3:06           ` JeffleXu
2021-09-18  3:06           ` JeffleXu
2021-09-19 19:45         ` Vivek Goyal
2021-09-19 19:45           ` Vivek Goyal
2021-09-19 19:45           ` Vivek Goyal
2021-09-22  8:16           ` JeffleXu
2021-09-22  8:16             ` JeffleXu
2021-09-22  8:16             ` JeffleXu
2021-08-17 12:39   ` Vivek Goyal
2021-08-17 12:39     ` [Virtio-fs] " Vivek Goyal
2021-08-17 12:39     ` Vivek Goyal
2021-08-17 13:22     ` JeffleXu
2021-08-17 13:22       ` [Virtio-fs] " JeffleXu
2021-08-17 13:22       ` JeffleXu
2021-08-17 14:08       ` Miklos Szeredi
2021-08-17 14:08         ` [Virtio-fs] " Miklos Szeredi
2021-08-18  3:39         ` JeffleXu
2021-08-18  3:39           ` [Virtio-fs] " JeffleXu
2021-08-18  3:39           ` JeffleXu
2021-08-18  5:08           ` Miklos Szeredi
2021-08-18  5:08             ` [Virtio-fs] " Miklos Szeredi
2021-08-18 16:58             ` Vivek Goyal
2021-08-18 16:58               ` [Virtio-fs] " Vivek Goyal
2021-08-18 16:58               ` Vivek Goyal
2021-09-03  5:30         ` JeffleXu
2021-09-03  5:30           ` [Virtio-fs] " JeffleXu
2021-09-03  5:30           ` JeffleXu
2021-09-07 14:51           ` Miklos Szeredi
2021-09-07 14:51             ` [Virtio-fs] " Miklos Szeredi
2021-08-17 14:57       ` Vivek Goyal
2021-08-17 14:57         ` [Virtio-fs] " Vivek Goyal
2021-08-17 14:57         ` Vivek Goyal
2021-08-18  5:20         ` JeffleXu
2021-08-18  5:20           ` [Virtio-fs] " JeffleXu
2021-08-18  5:20           ` JeffleXu
2021-08-30 23:31         ` [Virtio-fs] " Liu Bo

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