Date: Wed, 24 May 2006 10:18:50 +0900
From: Yasunori Goto <y-goto@jp.fujitsu.com>
To: Dave Hansen <haveblue@us.ibm.com>
Subject: Re: [Patch]Fix spanned_pages is not updated at a case of memory hot-add.
Cc: Andrew Morton <akpm@osdl.org>,
       Linux Kernel ML <linux-kernel@vger.kernel.org>
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> I really don't like the idea of having this variable called "new_"
> something.  That implies that this is what the new end_pfn is going to
> be.  The *new* one.  In reality, it is what it _might_ have been.  How
> about "tmp_zone_end_pfn"?
> 
> This practice of dealing with spanned_pages is a real pain. 
> 
> I generally try to avoid max/min in code, but this struck me as possibly
> being useful.  Do you find this easier to read, or your patch?

Ah, I think using max is better due to smaller code, indeed.

> 
> diff -puN mm/memory_hotplug.c~fix-spanned-pages mm/memory_hotplug.c
> --- work/mm/memory_hotplug.c~fix-spanned-pages	2006-05-23 09:04:31.000000000 -0700
> +++ work-dave/mm/memory_hotplug.c	2006-05-23 09:22:18.000000000 -0700
> @@ -91,8 +91,8 @@ static void grow_zone_span(struct zone *
>  	if (start_pfn < zone->zone_start_pfn)
>  		zone->zone_start_pfn = start_pfn;
>  
> -	if (end_pfn > old_zone_end_pfn)
> -		zone->spanned_pages = end_pfn - zone->zone_start_pfn;
> +	zone->spanned_pages = max(old_zone_end_pfn, end_pfn) -
> +				zone->zone_start_pfn);
                                                    ^
                                       this parentheses is redundant. :-)

Could you fix and repost it? Or should I?

-- 
Yasunori Goto 


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