Messages in this thread Patch in this message | | | Date | Wed, 8 Jun 2011 10:15:06 +0900 | From | KAMEZAWA Hiroyuki <> | Subject | [BUGFIX][PATCH] fix node hotplug zonelist build |
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At memory hotplug, we reflesh zonelists when we online a page in a new zone. It means that 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 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> --- mm/memory_hotplug.c | 6 ++++++ 1 file changed, 6 insertions(+)
Index: linux-3.0-rc1/mm/memory_hotplug.c =================================================================== --- linux-3.0-rc1.orig/mm/memory_hotplug.c +++ linux-3.0-rc1/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; }
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