Re: [Qemu-devel] [PATCH v4 18/29] hostmem: add file-based HostMemoryBackend

[Michael S. Tsirkin]

On Tue, Jun 10, 2014 at 10:56:42AM +0200, Paolo Bonzini wrote:
> Il 10/06/2014 10:30, Hu Tao ha scritto:
> >On Tue, Jun 10, 2014 at 01:09:32AM -0400, Paolo Bonzini wrote:
> >>
> >>>>>+#define TYPE_MEMORY_BACKEND_FILE "memory-backend-file"
> >>>>how about naming it after what it really is? "memory-backend-hugepage"
> >>>>Later we could split it into generic superclass mmap-ed
> >>>>"memory-backend-file" and have TPH specific code moved into this backend.
> >>>
> >>>OK.
> >>
> >>Actually I don't think there's anything hugepage-specific in this backend
> >>(except perhaps passing a path instead of a filename).  It could be used
> >>with a tmpfs backing storage like /dev/shm.
> >
> >What's the point compared to memory-backend-ram?
> 
> That you can use shared memory, for example together with vhost-user.

I don't think it's a good idea until THP supports shared memory.

> >Igor suggested memory-backend-file be compiled only for Linux. Does this mean
> >memory-backend-file shuold be compiled also for systems supporting tmpfs
> >or like?
> 
> Yes, I think it should be compiled on all POSIX systems.  But it can be done
> later.
> 
> Paolo

For example when someone actually requests this :).
Which is unlikely to happen soon I think.

-- 
MST