Date: Tue, 9 Feb 2010 14:33:07 -0800
From: Andrew Morton <akpm@linux-foundation.org>
To: Yinghai Lu <yinghai@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>,
       "H. Peter Anvin" <hpa@zytor.com>,
       Linus Torvalds <torvalds@linux-foundation.org>,
       Jesse Barnes <jbarnes@virtuousgeek.org>,
       Christoph Lameter <cl@linux-foundation.org>,
       linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org
Subject: Re: [PATCH 15/35] x86: make 64 bit use early_res instead of bootmem
 before slab
Message-Id: <20100209143307.86184916.akpm@linux-foundation.org>
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	<1265743966-17065-16-git-send-email-yinghai@kernel.org>
	<20100209122632.fc4be9c1.akpm@linux-foundation.org>
	<4B71D580.805@kernel.org>
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On Tue, 09 Feb 2010 13:37:04 -0800
Yinghai Lu <yinghai@kernel.org> wrote:

> On 02/09/2010 12:26 PM, Andrew Morton wrote:
> > On Tue, 09 Feb 2010 11:32:26 -0800
> > Yinghai Lu <yinghai@kernel.org> wrote:
> > 
> >> +u64 __init find_early_area(u64 ei_start, u64 ei_last, u64 start, u64 end,
> >> +			 u64 size, u64 align)
> >> +{
> >> +	u64 addr, last;
> >> +
> >> +	addr = round_up(ei_start, align);
> > 
> > Can we use include/linux/log2.h:roundup_pow_of_two() in this patchset?
> 
> no, that is not what we want.
> 
> 
> /**
>  * roundup_pow_of_two - round the given value up to nearest power of two
>  * @n - parameter
>  *
>  * round the given value up to the nearest power of two
>  * - the result is undefined when n == 0
>  * - this can be used to initialise global variables from constant data
>  */
> #define roundup_pow_of_two(n)                   \
> (                                               \
>         __builtin_constant_p(n) ? (             \
>                 (n == 1) ? 1 :                  \
>                 (1UL << (ilog2((n) - 1) + 1))   \
>                                    ) :          \
>         __roundup_pow_of_two(n)                 \
>  )
> 

err, crap, yeah.

It would be nice to fix all this up, and get the private round_up()
stuff out of x86 and into kernel.h.

The present naming scheme is ghastly:

ALIGN
DIV_ROUND_UP
roundup
round_up
round_down

Where round_up and ALIGN are kinda maybe the same.


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