Il 20/06/2013 10:30, Igor Mammedov ha scritto: > On Wed, 19 Jun 2013 15:29:31 +0200 > Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote: > >> Il 19/06/2013 15:20, Batalov Eugene ha scritto: >>> >>> I've missed this detail. It looks like Igor's patch doesn't bring >>> secondary cpus kvm_clocksource behavior back to one before the regression, >>> Before the regression per_cpu variables are used to allocate >>> kvm_pv_clock areas. >>> To to usage of percpu variables bootstrap cpu kvm_clock area contents >>> were copied to smp secondary cpus kvm_clock areas when they were started. >>> Bootstrap cpu kvm_clock area was not zeroed at this time. >>> So kvm_pv_clock for secondary cpus never returned "zero" clock before >>> the regression. >>> >>> During the analysis of the bug I introduced idea to return zero before >>> kvm clocksource is initialized for secondary cpus >>> just like bootstrap cpu does on kernel boot. You can read that in BZ. >> >> Yes, this is why I prefer to invert the two function calls. But Igor's >> patch fixes the hang (trivially because version is even) and is more >> appropriate for -rc6. > > I'll post this swap shortly, but zeroing out hv_clock at init time, > would be still needed to provide sane values there if ftrace enabled > at that time. Fine! Please mention it (with --verbose flag) in the commit message. Paolo -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
