On Fri, 20 Jul 2007, Nick Piggin wrote:
>
> So you did. Then to answer that, yes it could be faster because there are
> stupid volatiles sprinkled all over the bitops code so you could easily
> end up having to do more loads. Does it make a real difference? Unlikely,
> but David loves counting cycles :)
I thought we long long since removed the volatiles. They are buggy and
horrible, and we really want to let the compiler combine multiple
test-bits, and if they matter that implies locking is buggy or something
worse..
Ie we'd *want*
if (test_bit(x, y) || test_bit(z,y))
to be rewritten by the compiler as testing bits x/z at the same time.
But now I'm too scared to look.
Linus
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