[libvirt] [BUG] mlock support breakage

[Luiz Capitulino]

On Mon, 13 Mar 2017 18:16:49 +0000
"Daniel P. Berrange" <berrange at redhat.com> wrote:

> On Mon, Mar 13, 2017 at 02:08:30PM -0400, Luiz Capitulino wrote:
> > On Mon, 13 Mar 2017 13:53:33 -0400
> > Luiz Capitulino <lcapitulino at redhat.com> wrote:
> >   
> > > OK, you're right. I personally don't like we're putting a random cap
> > > on QEMU memory allocations, but if it's large enough it shouldn't be
> > > a problem (I hope).  
> > 
> > The I hope part meaning, if we do find legitimate reasons for QEMU's
> > address space to go beyond $LARGE_NUMBER, it will be means of guests
> > randomly crashing when using <locked/>.  
> 
> NB if we did enforce $RAM + $LARGE_NUMBER, then I'd suggest we did
> set a default hard_limit universally once more, not only set a mlock
> limit when using <locked/>. This would at least ensure we see consistent
> (bad) behaviour rather than have edge cases that only appeared when
> <locked/> was present.

Makes me even more nervous, but I agree with your reasoning.

Btw, do we have a volunteer to do this work? Andrea?

> 
> We would need $LARGE_NUMBER to be much more conservative than what we
> used in the past though, to avoid hitting the same problems once again.
> 
> Regards,
> Daniel