Commit 959ecc48 authored by KAMEZAWA Hiroyuki's avatar KAMEZAWA Hiroyuki Committed by Linus Torvalds

mm/memory_hotplug.c: fix building of node hotplug zonelist

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: default avatarKAMEZAWA Hiroyuki <>
Cc: Mel Gorman <>
Cc: Dave Hansen <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent de695e15
......@@ -494,6 +494,12 @@ static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
/* 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.
return pgdat;
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