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Re: [PATCH 0/2] RFC: add -mem-shared option
From: |
Daniel P . Berrangé |
Subject: |
Re: [PATCH 0/2] RFC: add -mem-shared option |
Date: |
Fri, 29 Nov 2019 09:27:13 +0000 |
User-agent: |
Mutt/1.12.1 (2019-06-15) |
On Fri, Nov 29, 2019 at 11:30:51AM +0400, Marc-André Lureau wrote:
> Hi
>
> On Fri, Nov 29, 2019 at 11:03 AM Gerd Hoffmann <address@hidden> wrote:
> >
> > On Thu, Nov 28, 2019 at 06:15:16PM +0400, Marc-André Lureau wrote:
> > > Hi,
> > >
> > > Setting up shared memory for vhost-user is a bit complicated from
> > > command line, as it requires NUMA setup such as: m 4G -object
> > > memory-backend-file,id=mem,size=4G,mem-path=/dev/shm,share=on -numa
> > > node,memdev=mem.
> > >
> > > Instead, I suggest to add a -mem-shared option for non-numa setups,
> > > that will make the -mem-path or anonymouse memory shareable.
> >
> > Is it an option to just use memfd by default (if available)?
>
> Yes, with a fallback path currently using a temporary file under /tmp
> (we may want to use shm_open() instead, or a different location such
> as XDG_RUNTIME_DIR? - and use O_TMPFILE)
We can't assume either /tmp or XDG_RUNTIME_DIR is on tmpfs as that is no
where near standard across all OS distros, and even if on tmpfs these
dirs can be size limited to a significant subset of available RAM. IOW
we can't safely use them unless explicitly told to.
Regards,
Daniel
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- Re: [PATCH 0/2] RFC: add -mem-shared option, (continued)
Re: [PATCH 0/2] RFC: add -mem-shared option, Dr. David Alan Gilbert, 2019/11/28
Re: [PATCH 0/2] RFC: add -mem-shared option, no-reply, 2019/11/28
Re: [PATCH 0/2] RFC: add -mem-shared option, no-reply, 2019/11/29
Re: [PATCH 0/2] RFC: add -mem-shared option, Gerd Hoffmann, 2019/11/29
Re: [PATCH 0/2] RFC: add -mem-shared option, Paolo Bonzini, 2019/11/29
Re: [PATCH 0/2] RFC: add -mem-shared option, Daniel P . Berrangé, 2019/11/29
Re: [PATCH 0/2] RFC: add -mem-shared option, Paolo Bonzini, 2019/11/29
Re: [PATCH 0/2] RFC: add -mem-shared option, Igor Mammedov, 2019/11/29
Re: [PATCH 0/2] RFC: add -mem-shared option, Paolo Bonzini, 2019/11/29