Re: [PATCH] bitops: simplify generic bit finding functions

Alexander van Heukelum
2008-04-28T14:58:51Z

On Sun, 27 Apr 2008 13:26:34 -0700 (PDT), "Linus Torvalds"
<torvalds@linux-foundation.org> said:
> On Sun, 27 Apr 2008, Harvey Harrison wrote:
> >
> > No need for a sentinal if we explicitly catch the no bits/all bits set
> > cases, make it clear they are special cases returning size/BITS_PER_LONG.
>
> These things need to be re-done anyway. David already complained that the
> thing inlines to something much much too big.
>
> Let's just make it not be an inline at all.

Hello,

I think that's the wrong way to go about it. The problem that David
Miller pointed out was that the small-bitmap optimization caused an
inliningdisaster. Apparently, the generic version of __ffs is very
big on sparc64. In my opinion the implementation of __ffs should be
made out of line. If you move the wrapper of find_first_bit etc
out of line, all possibilities of optimization will be destroyed.
Better to remove them completely, then.

Greetings,
Alexander

> Linus
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Alexander van Heukelum
heukelum@fastmail.fm

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