On Fri, 14 Sep 2012 20:00:09 +0900
Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx> wrote:
> > @@ -187,9 +184,10 @@ void register_page_bootmem_info_node(struct pglist_data *pgdat)
> > end_pfn = pfn + pgdat->node_spanned_pages;
> >
> > /* register_section info */
> > - for (; pfn < end_pfn; pfn += PAGES_PER_SECTION)
> > - register_page_bootmem_info_section(pfn);
> > -
> > + for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
> > + if (pfn_valid(pfn) && (pfn_to_nid(pfn) == node))
>
> I cannot judge whether your configuration is correct or not.
> Thus if it is correct, I want a comment of why the node check is
> needed. In usual configuration, a node does not span the other one.
> So it is natural that "pfn_to_nid(pfn) is same as "pgdat->node_id".
> Thus we may remove the node check in the future.
yup. How does this look?
--- a/mm/memory_hotplug.c~memory-hotplug-fix-a-double-register-section-info-bug-fix
+++ a/mm/memory_hotplug.c
@@ -185,6 +185,12 @@ void register_page_bootmem_info_node(str
/* register_section info */
for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
+ /*
+ * Some platforms can assign the same pfn to multiple nodes - on
+ * node0 as well as nodeN. To avoid registering a pfn against
+ * multiple nodes we check that this pfn does not already
+ * reside in some other node.
+ */
if (pfn_valid(pfn) && (pfn_to_nid(pfn) == node))
register_page_bootmem_info_section(pfn);
}
_
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