Re: 2.6.35-rc1 regression with pvclock and smp guests

Glauber Costa
2010-10-13T12:18:09Z

On Mon, Oct 11, 2010 at 10:47:16AM -1000, Zachary Amsden wrote:
> On 10/08/2010 10:59 PM, Arjan Koers wrote:
> >On 2010-10-09 08:29, Michael Tokarev wrote:
> >...
> >>The result is that no released linux kernel boots
> >>in smp in kvm, which is a linux virtual machine.
> >>That's irony, isn't it?
> >>
> >>I wonder how distributions (which are almost all based
> >>on 2.6.32 nowadays) will deal with the issue.. ;)
> >It looks like Debian solved it on their 2.6.32 guest by
> >reverting the commit that makes it hang:
> >http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=588426
>
> That's not a wise choice, the commit is needed to prevent clocks
> going backwards. It then caused some fallout issues with clobbers,
> which I believe hpa fixed, but there were several rounds of it.
>
> Glauber, perhaps, has a better idea of what patches are needed for
> the host side kvmclock. I've mostly been working on the server
> side.
No, all the recent patches I wrote towards fixing kvmclock problems
touch the guest. The host side ones are nice to have, but not stable/needed
material