[libvirt] Bug in virsh memtune on RHEL6?

[Nikunj A. Dadhania]

On Fri, 7 Jan 2011 03:16:56 +1100, Justin Clift <jclift at redhat.com> wrote:
> On 07/01/2011, at 2:48 AM, Eric Blake wrote:
> > On 01/06/2011 08:29 AM, Justin Clift wrote:
> >> Hi all,
> >> 
> >> Getting strange numbers from the virsh memtune command on
> >> RHEL 6.  (git head compiled, rather than RHEL 6 packages)
> >> 
> >>  virsh # list
> >>   Id Name                 State
> >>  ----------------------------------
> >>    4 Fedora_14_x64        running
> >> 
> >>  virsh # memtune Fedora_14_x64
> >>  hard_limit     : 9007199254740991
> >>  soft_limit     : 9007199254740991
> >>  swap_hard_limit: 9007199254740991
> >> 
> >> Those numbers are supposed to be kilobytes, but the host
> >> box itself only has 12GB ram.
> >> 
> >> Bug?
> > 
> > Smells like a case of mistakenly treating either -1 or INT64_MAX as a
> > valid value (that integer is 0x1f_ffff_ffff_ffff, which happens to be
> > UINT64_MAX>>11 or INT64_MAX>>10), rather than recognizing it as meaning
> > unlimited or undeterminable.  If unlimited is the intended meaning,
> > virsh can probably be taught to display it differently, perhaps by also
> > referencing the host's limits.
> 
> Yeah, that sounds like it might be the cause.
> 
As Eric suggested, thats the value for unlimited, i.e. -1(64bit) and then
(INT_MAX>>10) for getting kbytes. I will send a patch to display it as
unlimited.

Nikunj