From: JeffleXu <jefflexu@linux.alibaba.com>
To: Vivek Goyal <vgoyal@redhat.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>,
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 13:20:43 +0800 [thread overview]
Message-ID: <bde1d657-0aa4-324d-064e-711efa893c2f@linux.alibaba.com> (raw)
In-Reply-To: <YRvOZI3CvLsF96JA@redhat.com>
On 8/17/21 10:57 PM, Vivek Goyal wrote:
> On Tue, Aug 17, 2021 at 09:22:53PM +0800, JeffleXu wrote:
>>
>>
>> On 8/17/21 8:39 PM, Vivek Goyal wrote:
>>> On Tue, Aug 17, 2021 at 10:06:53AM +0200, Miklos Szeredi 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?
>>>
>>> Initially I thought that they needed it because they are downloading
>>> files on the fly from server. So they don't want to enable dax on the file
>>> till file is completely downloaded.
>>
>> Right, it's our initial requirement.
>>
>>
>>> But later I realized that they should
>>> be able to block in FUSE_SETUPMAPPING call and make sure associated
>>> file section has been downloaded before returning and solve the problem.
>>> So that can't be the primary reason.
>>
>> Saying we want to access 4KB of one file inside guest, if it goes
>> through FUSE request routine, then the fuse daemon only need to download
>> this 4KB from remote server. But if it goes through DAX, then the fuse
>> daemon need to download the whole DAX window (e.g., 2MB) from remote
>> server, so called amplification. Maybe we could decrease the DAX window
>> size, but it's a trade off.
>
> Downloading 2MB chunk should not be a big issue (IMHO).
Then the latency increases. Latency really matters in our use case.
> And if this
> turns out to be real concern, we could experiment with a smaller
> mapping granularity.
>
--
Thanks,
Jeffle
WARNING: multiple messages have this Message-ID (diff)
From: JeffleXu <jefflexu@linux.alibaba.com>
To: Vivek Goyal <vgoyal@redhat.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>,
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>,
Stefan Hajnoczi <stefanha@redhat.com>,
linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH v4 0/8] fuse,virtiofs: support per-file DAX
Date: Wed, 18 Aug 2021 13:20:43 +0800 [thread overview]
Message-ID: <bde1d657-0aa4-324d-064e-711efa893c2f@linux.alibaba.com> (raw)
In-Reply-To: <YRvOZI3CvLsF96JA@redhat.com>
On 8/17/21 10:57 PM, Vivek Goyal wrote:
> On Tue, Aug 17, 2021 at 09:22:53PM +0800, JeffleXu wrote:
>>
>>
>> On 8/17/21 8:39 PM, Vivek Goyal wrote:
>>> On Tue, Aug 17, 2021 at 10:06:53AM +0200, Miklos Szeredi 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?
>>>
>>> Initially I thought that they needed it because they are downloading
>>> files on the fly from server. So they don't want to enable dax on the file
>>> till file is completely downloaded.
>>
>> Right, it's our initial requirement.
>>
>>
>>> But later I realized that they should
>>> be able to block in FUSE_SETUPMAPPING call and make sure associated
>>> file section has been downloaded before returning and solve the problem.
>>> So that can't be the primary reason.
>>
>> Saying we want to access 4KB of one file inside guest, if it goes
>> through FUSE request routine, then the fuse daemon only need to download
>> this 4KB from remote server. But if it goes through DAX, then the fuse
>> daemon need to download the whole DAX window (e.g., 2MB) from remote
>> server, so called amplification. Maybe we could decrease the DAX window
>> size, but it's a trade off.
>
> Downloading 2MB chunk should not be a big issue (IMHO).
Then the latency increases. Latency really matters in our use case.
> And if this
> turns out to be real concern, we could experiment with a smaller
> mapping granularity.
>
--
Thanks,
Jeffle
_______________________________________________
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization
WARNING: multiple messages have this Message-ID (diff)
From: JeffleXu <jefflexu@linux.alibaba.com>
To: Vivek Goyal <vgoyal@redhat.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>,
virtualization@lists.linux-foundation.org,
virtio-fs-list <virtio-fs@redhat.com>,
Joseph Qi <joseph.qi@linux.alibaba.com>,
linux-fsdevel@vger.kernel.org
Subject: Re: [Virtio-fs] [PATCH v4 0/8] fuse,virtiofs: support per-file DAX
Date: Wed, 18 Aug 2021 13:20:43 +0800 [thread overview]
Message-ID: <bde1d657-0aa4-324d-064e-711efa893c2f@linux.alibaba.com> (raw)
In-Reply-To: <YRvOZI3CvLsF96JA@redhat.com>
On 8/17/21 10:57 PM, Vivek Goyal wrote:
> On Tue, Aug 17, 2021 at 09:22:53PM +0800, JeffleXu wrote:
>>
>>
>> On 8/17/21 8:39 PM, Vivek Goyal wrote:
>>> On Tue, Aug 17, 2021 at 10:06:53AM +0200, Miklos Szeredi 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?
>>>
>>> Initially I thought that they needed it because they are downloading
>>> files on the fly from server. So they don't want to enable dax on the file
>>> till file is completely downloaded.
>>
>> Right, it's our initial requirement.
>>
>>
>>> But later I realized that they should
>>> be able to block in FUSE_SETUPMAPPING call and make sure associated
>>> file section has been downloaded before returning and solve the problem.
>>> So that can't be the primary reason.
>>
>> Saying we want to access 4KB of one file inside guest, if it goes
>> through FUSE request routine, then the fuse daemon only need to download
>> this 4KB from remote server. But if it goes through DAX, then the fuse
>> daemon need to download the whole DAX window (e.g., 2MB) from remote
>> server, so called amplification. Maybe we could decrease the DAX window
>> size, but it's a trade off.
>
> Downloading 2MB chunk should not be a big issue (IMHO).
Then the latency increases. Latency really matters in our use case.
> And if this
> turns out to be real concern, we could experiment with a smaller
> mapping granularity.
>
--
Thanks,
Jeffle
next prev parent reply other threads:[~2021-08-18 5:20 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
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 [this message]
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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