Re: [PATCH RESEND] memory hotplug: fix a double register section info bug

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



2012/09/15 5:14, Andrew Morton wrote:
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?

Looks good to me.

Reviewed-by: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx>


--- 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);
  	}
_

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>



--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>


[Index of Archives]     [Linux ARM Kernel]     [Linux ARM]     [Linux Omap]     [Fedora ARM]     [IETF Annouce]     [Bugtraq]     [Linux]     [Linux OMAP]     [Linux MIPS]     [ECOS]     [Asterisk Internet PBX]     [Linux API]