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

Avi Kivity
2010-04-19T10:50:44Z

On 04/19/2010 01:39 PM, Peter Zijlstra wrote:
> On Fri, 2010-04-16 at 13:36 -0700, Jeremy Fitzhardinge wrote:
>
>>> + do {
>>> + last = last_value;
>>>
>>>
>> Does this need a barrier() to prevent the compiler from re-reading
>> last_value for the subsequent lines? Otherwise "(ret< last)" and
>> "return last" could execute with different values for "last".
>>
>>
> ACCESS_ONCE() is your friend.
>

I think it's implied with atomic64_read().

--
error compiling committee.c: too many arguments to function