Re: [PATCH] mem-hotplug: fix node spanned pages when we have a node with only zone_movable

[Oscar Salvador <osalvador@suse.de>]

On Tue, Apr 02, 2019 at 04:57:11PM +0200, Oscar Salvador wrote:
> On Tue, Apr 02, 2019 at 12:11:16PM +0800, Linxu Fang wrote:
> > commit <342332e6a925> ("mm/page_alloc.c: introduce kernelcore=mirror
> > option") and series patches rewrote the calculation of node spanned
> > pages.
> > commit <e506b99696a2> (mem-hotplug: fix node spanned pages when we have a
> > movable node), but the current code still has problems,
> > when we have a node with only zone_movable and the node id is not zero,
> > the size of node spanned pages is double added.
> > That's because we have an empty normal zone, and zone_start_pfn or
> > zone_end_pfn is not between arch_zone_lowest_possible_pfn and
> > arch_zone_highest_possible_pfn, so we need to use clamp to constrain the
> > range just like the commit <96e907d13602> (bootmem: Reimplement
> > __absent_pages_in_range() using for_each_mem_pfn_range()).
> 
> So, let me see if I understood this correctly:
> 
> When calling zone_spanned_pages_in_node() for any node which is not node 0,
> 
> > *zone_start_pfn = arch_zone_lowest_possible_pfn[zone_type];
> > *zone_end_pfn = arch_zone_highest_possible_pfn[zone_type];
> 
> will actually set zone_start_pfn/zone_end_pfn to the values from node0's
> ZONE_NORMAL?

Of course, I meant when calling it being zone_type == ZONE_NORMAL.

-- 
Oscar Salvador
SUSE L3