On Mon, Oct 23, 2017 at 07:41:57AM -0400, Marc-André Lureau wrote:
>
>
> ----- Original Message -----
> > On Mon, Oct 23, 2017 at 10:59:09AM +0100, Marc-André Lureau wrote:
> > > Add a new memory backend, similar to hostmem-file, except that it
> > > doesn't need to create files. It also enforces memory sealing.
> > >
> > > This backend is mainly useful for sharing the memory with other
> > > processes.
> > >
> > > Note that Linux supports transparent huge-pages of shmem/memfd memory
> > > since 4.8. It is relatively easier to set up THP than a dedicate
> > > hugepage mount point by using "madvise" in
> > > /sys/kernel/mm/transparent_hugepage/shmem_enabled.
> > >
> > > Since 4.14, memfd allows to set hugetlb requirement explicitly.
> > >
> > > Usage:
> > > -object memory-backend-memfd,id=mem1,size=1G
> >
> > [snip]
> >
> > > +static void
> > > +memfd_backend_class_init(ObjectClass *oc, void *data)
> > > +{
> > > + HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc);
> > > +
> > > + bc->alloc = memfd_backend_memory_alloc;
> > > +
> > > + object_class_property_add_bool(oc, "hugetlb",
> > > + memfd_backend_get_hugetlb,
> > > + memfd_backend_set_hugetlb,
> > > + &error_abort);
> >
> > I tend to think that instead of a bool hugetlb, we should take an
> > integer page size instead eg hugepagesize=2M instead of hugetlb=true
> >
>
> Well, how would you then create a memfd without explicit hugetlb
> request or one with default hugetlb size?
Hmm, yes, libvirt would not need that, but that would be useful still for
direct QEMU users.
> I think size should be a different property. I'll add it.
Yep ok
Regards,
Daniel
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