Hi Eduardo On Fri, Jun 23, 2017 at 11:09 PM Eduardo Habkost <ehabk...@redhat.com> wrote:
> On Wed, Jun 21, 2017 at 04:02:18PM +0200, 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. > > How exactly can the memfd be used to share memory? Is there an existing > mechanism for sharing the memfd file descriptor with another process Since there is no backing file, the traditional mechanism is by passing fd, via socket ancillary data or forking etc.. Both ivshmem and vhost-user have such messages, with eventually details for the memory map usage. > > > > 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. > > > > Usage: > > -object memory-backend-memfd,id=mem1,size=1G > > > > Signed-off-by: Marc-André Lureau <marcandre.lur...@redhat.com> > > --- > > backends/hostmem-memfd.c | 67 > ++++++++++++++++++++++++++++++++++++++++++++++++ > > backends/Makefile.objs | 2 ++ > > qemu-options.hx | 11 ++++++++ > > 3 files changed, 80 insertions(+) > > create mode 100644 backends/hostmem-memfd.c > > > [...] > > -- > Eduardo > > -- Marc-André Lureau
