On Tue, 12 Dec 2006, Zoltan Menyhart wrote:
> Let's assume the bit test & set is already set, why is then the
> cmpxchg_acq() executed? Cannot we just return, e.g. like this?
>
> do {
> old = *m;
> if (old & bit)
> return 1;
> new = old | bit;
> } while (cmpxchg_acq(m, old, new) != old);
I think this will work. However, usually you execute bit test and test
because the bit is not set and you want to set it. This change would
optimize a rarely taken path. Probably not worth it.
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