From: "Daniel P. Berrangé" <berrange@redhat.com>
To: "Marc-André Lureau" <marcandre.lureau@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>,
qemu-devel <qemu-devel@nongnu.org>,
Gerd Hoffmann <kraxel@redhat.com>,
Stefan Hajnoczi <stefanha@redhat.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Richard Henderson <rth@twiddle.net>
Subject: Re: [PATCH 0/2] RFC: add -mem-shared option
Date: Fri, 29 Nov 2019 09:27:13 +0000 [thread overview]
Message-ID: <20191129092713.GA2260471@redhat.com> (raw)
In-Reply-To: <CAMxuvawieN7JQZkRku19v5X-o6q664Wz1Rtx3+Wz3d33m-7Tug@mail.gmail.com>
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 <kraxel@redhat.com> 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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next prev parent reply other threads:[~2019-11-29 9:36 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-28 14:15 [PATCH 0/2] RFC: add -mem-shared option Marc-André Lureau
2019-11-28 14:15 ` [PATCH 1/2] memfd: add qemu_memfd_open() Marc-André Lureau
2019-11-28 14:15 ` [PATCH 2/2] Add -mem-shared option Marc-André Lureau
2019-11-28 16:14 ` Eduardo Habkost
2019-11-28 16:28 ` Igor Mammedov
2019-11-28 20:31 ` Marc-André Lureau
2019-11-29 10:07 ` Igor Mammedov
2019-11-29 10:11 ` Paolo Bonzini
2019-11-29 12:01 ` Markus Armbruster
2019-11-29 20:31 ` Eduardo Habkost
2019-11-29 12:16 ` Igor Mammedov
2019-11-29 17:46 ` Paolo Bonzini
2019-12-02 7:39 ` Igor Mammedov
2019-12-02 21:00 ` Eduardo Habkost
2019-12-03 8:56 ` Thomas Huth
2019-12-03 14:43 ` Igor Mammedov
2019-12-09 20:58 ` Eduardo Habkost
2019-12-10 10:34 ` Markus Armbruster
2019-12-10 13:09 ` Igor Mammedov
2019-12-03 21:34 ` Eduardo Habkost
2019-11-28 16:10 ` [PATCH 0/2] RFC: add " Eduardo Habkost
2019-11-29 9:18 ` Igor Mammedov
2019-11-29 9:31 ` Paolo Bonzini
2019-11-29 10:23 ` Igor Mammedov
2019-11-29 11:21 ` Paolo Bonzini
2019-11-29 20:21 ` Eduardo Habkost
2019-12-01 15:40 ` Marc-André Lureau
2019-12-01 18:03 ` Paolo Bonzini
2019-11-28 16:59 ` Dr. David Alan Gilbert
2019-11-29 9:23 ` Igor Mammedov
2019-12-13 11:39 ` Stefan Hajnoczi
2019-12-13 13:12 ` Igor Mammedov
2019-11-29 4:37 ` no-reply
2019-11-29 5:34 ` no-reply
2019-11-29 7:02 ` Gerd Hoffmann
2019-11-29 7:30 ` Marc-André Lureau
2019-11-29 9:27 ` Daniel P. Berrangé [this message]
2019-11-29 9:31 ` Marc-André Lureau
2019-11-29 9:42 ` Daniel P. Berrangé
2019-11-29 9:45 ` Marc-André Lureau
2019-11-29 11:44 ` Gerd Hoffmann
2019-11-29 9:33 ` Paolo Bonzini
2019-11-29 9:39 ` Daniel P. Berrangé
2019-11-29 9:52 ` Paolo Bonzini
2019-11-29 10:13 ` Igor Mammedov
2019-11-29 11:20 ` Paolo Bonzini
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