From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jeremy Fitzhardinge <jeremy@goop.org>
Subject: Re: [PATCH 2/6] Add a global synchronization point for pvclock
Date: Tue, 27 Apr 2010 11:00:35 -0700
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Cc: Glauber Costa <glommer@redhat.com>, kvm@vger.kernel.org,
	linux-kernel@vger.kernel.org, avi@redhat.com,
	Zachary Amsden <zamsden@redhat.com>
To: Marcelo Tosatti <mtosatti@redhat.com>
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On 04/27/2010 06:28 AM, Marcelo Tosatti wrote:
>> +	last = atomic64_read(&last_value);
>> +	do {
>> +		if (ret < last)
>> +			return last;
>> +		last = atomic64_cmpxchg(&last_value, last, ret);
>> +	} while (unlikely(last != ret));
>>     
> Wraparound?
>   

If the units nanoseconds, it's good for ~500,000 years of uptime.

    J