On 23/12/2014 11:23, Santosh Shukla wrote: > > > No. kvm_guest_time_update is called by vcpu_enter_guest, while the vCPU > is not running, so it's entirely atomic from the point of view of > the guest. > > > Then checking odd value for version field (at guest side: function > pvclock_clocksource_read / pvclock_read_flag) is redundant considering > that kvm_guest_time_update incremented by 2.
The code is common to Xen and KVM. Xen uses seqlock semantics. The cost of one AND is not detectable. Paolo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
