Re: [Qemu-devel] [PATCH v3 1/7] Add -mem-share option

[Antonios Motakis]

On Sat, Dec 14, 2013 at 4:53 AM, Eric Blake <address@hidden> wrote:

On 12/13/2013 04:14 AM, Antonios Motakis wrote:
> This option complements -mem-path. It implies -mem-prealloc. If specified,
> the guest RAM is allocated as a shared memory object. If both -mem-path
> and -mem-share are provided, the memory is allocated from the HugeTLBFS
> supplied path, and then mmapped with MAP_SHARED.
>
> Signed-off-by: Antonios Motakis <address@hidden>
> Signed-off-by: Nikolay Nikolaev <address@hidden>
> ---

> +++ b/qemu-options.hx
> @@ -237,6 +237,15 @@ STEXI
>  Preallocate memory when using -mem-path.
>  ETEXI
>
> +DEF("mem-share", 0, QEMU_OPTION_mem_share,

Ouch.  Doesn't this mean you are defining a boolean option (absent or
present) as opposed to a qemuOpts option?  I've already been complaining
that other boolean opts are currently undiscoverable to QMP; they also
have the drawback of having no way to turn the option back off if an
alias turned it on earlier in the command line.  Can we use qemuOpts
here (so query-command-line-options can see it), and with a boolean
on/off argument (so it's not a one-way switch)?

Our implementation of mem-share complements mem-path and mem-prealloc.

Maybe these options should be combined as one QemuOpts with arguments?

Is this the memdev that is referred to by Paolo?

--
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org