Re: [libvirt] [BUG] mlock support breakage
On Mon, 13 Mar 2017 18:16:49 +0000
"Daniel P. Berrange" <berrange(a)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(a)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