On 18/07/16 18:24, Paolo Bonzini wrote: > > On 18/07/2016 09:17, Christian Borntraeger wrote: >> On 07/15/2016 09:52 AM, Suraj Jitindar Singh wrote: >>> >>> On 14/07/16 19:42, Paolo Bonzini wrote: >>>> On 13/07/2016 20:00, Christian Borntraeger wrote: >>>>>>>>> I thought u64 still existed on 32-bit architectures. unsigned long >>>>>>>>> would be fine but with the caveat that certain stats would overflow on >>>>>>>>> 32-bit architectures. >>>>>>> Yes, but not all 32-bit architectures can do atomic read-modify-write >>>>>>> (e.g. add) operations on 64-bit values. >>>>> So what about only doing it for the VCPU events? Those should be only >>>>> modified by one CPU. We would have some odd values on 32bit overflow, but >>>>> this will be certainly better than just start with 0 >>>> If that's good enough for PPC, that's fine. >>>> >>>> Paolo >>> I'm don't feel great about having vcpu_stats as u64 and vm_stats still as u32 >>> it's just a bit inconsistent. >>> >>> That being said, it's only the vcpu_stats which I require to be u64 at this >>> stage so it's possible to just upgrade those. >> Yes, its not nice, but we probably want to avoid the overhead of atomics. >> What about using u64 for vcpu_stats and unsigned long for vm_stats. This will be >> correct for anyone and on 64bit systems we get 64 bits for everything? > That makes sense. > > Paolo Sound good, I am happy with this. -- 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
