svn commit: r209119 - head/sys/sys

[Gabor PALI]

On 07/09/10 20:50, Robert Watson wrote:
> I think I have an e-mail in my in queue from you suggesting an
> alternative approach that I haven't yet gotten to due to utter
> saturation here.

That is why I CC'ed svn-src-head@ :)  (But I do not see any sign whether
my last email reached it -- I am not an that list.)  I hope other
committers will help me with this, because I would like to use it in my
project, and I think it would be useful in general.


>   I assume there are reasonable alternatives that work around the
> potential race with a small probability of a missed or extra update,
> or similar, which would be fine.

In a few words: As far as I know, 64-bit atomic counters could be
implemented by using cmpxchg8b or by a plain uint64_t variable protected
by some kind of locking(9).


Cheers,
:g