Re: get_order() broken !

From: Linus Torvalds
Date: Tue Mar 06 2007 - 12:14:24 EST




On Tue, 6 Mar 2007, Benjamin Herrenschmidt wrote:
>
> Ok, maybe I have lots of shit in my eyes.... but it looks like get_order
> in asm-generic/page.h is broken.
>
> AFAIK, get_order() should round up (and we have code here or there
> assuming such).
>
> However, it seems to assume that ilog2 rounds up, which it doesn't. It
> rounds down. At least the generic implementation seems to do so and the
> powerpc optimized one too.

Yeah, I think the recent get_order() changes to change it to use ilog2()
are just crap. I actually looked at it when it went in, but I assumed that
it had been tested. I don't think it has.

Let's just revert that entirely.

David, quick comments before I undo commit 39d61db0?

Linus
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