+ mm-memory_hotplugc-fix-building-of-node-hotplug-zonelist.patch added to -mm tree

[akpm@linux-foundation.org]

The patch titled
     mm/memory_hotplug.c: fix building of node hotplug zonelist
has been added to the -mm tree.  Its filename is
     mm-memory_hotplugc-fix-building-of-node-hotplug-zonelist.patch

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------------------------------------------------------
Subject: mm/memory_hotplug.c: fix building of node hotplug zonelist
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

During memory hotplug we refresh zonelists when we online a page in a new
zone.  It means that the node's zonelist is not initialized until pages
are onlined.  So for example, "nid" passed by MEM_GOING_ONLINE notifier
will point to NODE_DATA(nid) which has no zone fallback list.  Moreover,
if we hot-add cpu-only nodes, alloc_pages() will do no fallback.

This patch makes a zonelist when a new pgdata is available.

Note: in production, at fujitsu, memory should be onlined before cpu
      and our server didn't have any memory-less nodes and had no problems.

      But recent changes in MEM_GOING_ONLINE+page_cgroup
      will access not initialized zonelist of node.
      Anyway, there are memory-less node and we need some care.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/memory_hotplug.c |    6 ++++++
 1 file changed, 6 insertions(+)

diff -puN mm/memory_hotplug.c~mm-memory_hotplugc-fix-building-of-node-hotplug-zonelist mm/memory_hotplug.c
--- a/mm/memory_hotplug.c~mm-memory_hotplugc-fix-building-of-node-hotplug-zonelist
+++ a/mm/memory_hotplug.c
@@ -494,6 +494,12 @@ static pg_data_t __ref *hotadd_new_pgdat
 	/* init node's zones as empty zones, we don't have any present pages.*/
 	free_area_init_node(nid, zones_size, start_pfn, zholes_size);
 
+	/*
+	 * The node we allocated has no zone fallback lists. For avoiding
+	 * to access not-initialized zonelist, build here.
+	 */
+	build_all_zonelists(NULL);
+
 	return pgdat;
 }
 
_

Patches currently in -mm which might be from kamezawa.hiroyu@jp.fujitsu.com are

vmscanmemcg-memcg-aware-swap-token.patch
vmscanmemcg-memcg-aware-swap-token-fix.patch
vmscan-implement-swap-token-trace.patch
vmscan-implement-swap-token-priority-aging.patch
memcg-add-documentation-for-the-memorynumastat-api.patch
memcg-add-documentation-for-the-memorynumastat-api-fix.patch
mm-increase-reclaim_distance-to-30.patch
mm-fix-wrong-kunmap_atomic-pointer.patch
mm-memory_hotplugc-fix-building-of-node-hotplug-zonelist.patch