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 <kra...@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 -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
