Re: Linux v2.6.9 and GPL Buyout

[Martin Waitz]

hoi :)

On Wed, Oct 20, 2004 at 12:18:25AM -0400, Lee Revell wrote:
> I was doing this with perl and SQL before I
> ever heard of RCU.  If you don't want to lock a table (or didn't realize
> SQL had such a thing as table locking :-) you just fetch a value, make
> some calculation on it, then do the update iff that value has not
> changed.  If it has changed you fetch the new value and go back to step

what you described is not RCU.
it's more something like seqlocks

RCU means: you always read without any locking.
when you want to write, you create a new copy of the data instead
and switch over a pointer when you are done.
if you are sure that the old pointer is not used any move, you can
free the old value.

-- 
Martin Waitz

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