Re: [RFC] memory unplug v5 [5/6] page unplug

[Dave Hansen <hansendc@us.ibm.com>]

On Thu, 2007-06-14 at 16:04 +0900, KAMEZAWA Hiroyuki wrote:
> 
> +       if (start_pfn & (pageblock_nr_pages - 1))
> +               return -EINVAL;
> +       if (end_pfn & (pageblock_nr_pages - 1))
> +               return -EINVAL; 

After reading these, I'm still not sure I know what a pageblock is
supposed to be. :)  Did those come from Mel's patches?

In any case, I think it might be helpful to wrap up some of those
references in functions.  I was always looking at the patches trying to
find if "pageblock_nr_pages" was a local variable or not.  A function
would surely tell me.

static inline int pfn_is_pageblock_aligned(unsigned long pfn)
{
	return pfn & (pageblock_nr_pages - 1)
}

and, then you get

		BUG_ON(!pfn_is_pageblock_aligned(start_pfn));

It's pretty obvious what is going on, there. 

-- Dave

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