This is a note to let you know that I've just added the patch titled mm/hotplug: correctly add new zone to all other nodes' zone lists to the 3.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: mm-hotplug-correctly-add-new-zone-to-all-other-nodes-zone-lists.patch and it can be found in the queue-3.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 1bdb24f5ab52e64658f496a0dbfe04ffb56edaf6 Mon Sep 17 00:00:00 2001 From: Jiang Liu <jiang.liu@xxxxxxxxxx> Date: Tue, 31 Jul 2012 16:43:30 -0700 Subject: mm/hotplug: correctly add new zone to all other nodes' zone lists From: Jiang Liu <jiang.liu@xxxxxxxxxx> commit 08dff7b7d629807dbb1f398c68dd9cd58dd657a1 upstream. When online_pages() is called to add new memory to an empty zone, it rebuilds all zone lists by calling build_all_zonelists(). But there's a bug which prevents the new zone to be added to other nodes' zone lists. online_pages() { build_all_zonelists() ..... node_set_state(zone_to_nid(zone), N_HIGH_MEMORY) } Here the node of the zone is put into N_HIGH_MEMORY state after calling build_all_zonelists(), but build_all_zonelists() only adds zones from nodes in N_HIGH_MEMORY state to the fallback zone lists. build_all_zonelists() ->__build_all_zonelists() ->build_zonelists() ->find_next_best_node() ->for_each_node_state(n, N_HIGH_MEMORY) So memory in the new zone will never be used by other nodes, and it may cause strange behavor when system is under memory pressure. So put node into N_HIGH_MEMORY state before calling build_all_zonelists(). Signed-off-by: Jianguo Wu <wujianguo@xxxxxxxxxx> Signed-off-by: Jiang Liu <liuj97@xxxxxxxxx> Cc: Mel Gorman <mgorman@xxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxx> Cc: Minchan Kim <minchan@xxxxxxxxxx> Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx> Cc: Yinghai Lu <yinghai@xxxxxxxxxx> Cc: Tony Luck <tony.luck@xxxxxxxxx> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx> Cc: David Rientjes <rientjes@xxxxxxxxxx> Cc: Keping Chen <chenkeping@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx> Cc: Qiang Huang <h.huangqiang@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- mm/memory_hotplug.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -515,19 +515,20 @@ int __ref online_pages(unsigned long pfn zone->present_pages += onlined_pages; zone->zone_pgdat->node_present_pages += onlined_pages; - if (need_zonelists_rebuild) - build_all_zonelists(zone); - else - zone_pcp_update(zone); + if (onlined_pages) { + node_set_state(zone_to_nid(zone), N_HIGH_MEMORY); + if (need_zonelists_rebuild) + build_all_zonelists(zone); + else + zone_pcp_update(zone); + } mutex_unlock(&zonelists_mutex); init_per_zone_wmark_min(); - if (onlined_pages) { + if (onlined_pages) kswapd_run(zone_to_nid(zone)); - node_set_state(zone_to_nid(zone), N_HIGH_MEMORY); - } vm_total_pages = nr_free_pagecache_pages(); Patches currently in stable-queue which might be from jiang.liu@xxxxxxxxxx are queue-3.4/mm-hotplug-correctly-add-new-zone-to-all-other-nodes-zone-lists.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html