Re: [linux-pm] [PATCH] hibernation should work ok with memory hotplug

[Nigel Cunningham <ncunningham@crca.org.au>]

Hi.

On Mon, 2008-11-03 at 14:34 -0800, Dave Hansen wrote:
> A node might have a node_start_pfn=0 and a node_end_pfn=100 (and it may
> have only one zone).  But, there may be another node with
> node_start_pfn=10 and a node_end_pfn=20.  This loop:
> 
>         for_each_zone(zone) {
> 		...
>                 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
>                         if (page_is_saveable(zone, pfn))
>                                 memory_bm_set_bit(orig_bm, pfn);
>         }
> 
> will walk over the smaller node's pfn range multiple times.  Is this OK?
> 
> I think all you have to do to fix it is check page_zone(page) == zone
> and skip out if they don't match.

So pfn 10 in the first node refers to the same memory as pfn 10 in the
second node?

Regards,

Nigel