Commit 959ecc48 authored Jun 15, 2011 by KAMEZAWA Hiroyuki Committed by Linus Torvalds Jun 15, 2011

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: 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>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent de695e15

mm/memory_hotplug.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -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.
		*/
		build_all_zonelists(NULL);

		return pgdat;
		}

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