Re: [PATCH 1/5] Add a global synchronization point for pvclock

Glauber Costa
2010-10-26T10:49:26Z

On Tue, 2010-10-26 at 10:14 +0200, Avi Kivity wrote:
> On 10/26/2010 01:30 AM, Jeremy Fitzhardinge wrote:
> > Unfortunately this is breaking Xen save/restore: if you restore on a
> > host which was booted more recently than the save host, causing the
> > system time to be smaller. The effect is that the domain's time leaps
> > forward to a fixed point, and stays there until the host catches up to
> > the source host...
>
> Shouldn't save/restore also save the timebase?
>
> > I guess last_time needs to be reset on this type of event. I guess the
> > cleanest way would be for pvclock.c to register a sysdev suspend/resume
> > handler.
>
> Should be for Xen only; kvm save/restore doesn't involve the guest.

the suspend/resume path do adjust the time base. Maybe something similar
should be done ?