Re: [PATCH 0/2] RFC: add -mem-shared option

[Daniel P . Berrangé]

On Fri, Nov 29, 2019 at 10:33:39AM +0100, Paolo Bonzini wrote:
> On 29/11/19 10:27, Daniel P. Berrangé wrote:
> >> 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.
> 
> Agreed, mkstemp+shm_open seems better.  Perhaps this could be done in
> hostmem-memfd.c though, basically as a fallback option?  In principle
> one could even use getmntent to search for a hugetlbfs mount.

With mkstemp you still need to pick a location, and I don't think it
is clear there is a reliable choice that will always work.

Regards,
Daniel
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