On 12/14/2011 07:11 PM, Eric B Munson wrote: > > > > > > > > If I understand (please correct me if this is wrong) because this is > > > > only > > > > called from the watchdog, which disables preemption, we should be > > > > protected > > > > from something else writing to these flags. > > > > > > The host can write, but in that case race is harmless. > > > > Why is it harmless? You don't know what's in those other flags. > > > > -- > > error compiling committee.c: too many arguments to function > > > > Currently there is only one other flag in this byte (PVCLOCK_TSC_STABLE_BIT) > and it isset once in kvmclock_init(). It is highly unlikely that the vm will > be stopped during this init and have the flag clobbered. After the tsc stable > bit is written in the init, the field is read only outside of the guest paused > code.
Let's not lay minefields for us later to step into. Making this a cpu-local atomic (irq safe but not smp safe) is simple and easy, somehting like __this_cpu_and(). -- error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
