From d9e61dba0c73294e9e6761f290dce2049f06bfac Mon Sep 17 00:00:00 2001 From: Jiang Liu <jiang.liu@huawei.com> Date: Tue, 19 Mar 2013 12:36:58 +0100 Subject: mm/hotplug: correctly add new zone to all other nodes' zone lists 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@huawei.com> Signed-off-by: Jiang Liu <liuj97@gmail.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Michal Hocko <mhocko@suse.cz> Cc: Minchan Kim <minchan@kernel.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Tony Luck <tony.luck@intel.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: David Rientjes <rientjes@google.com> Cc: Keping Chen <chenkeping@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- mm/memory_hotplug.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index e0a3e51d5191..a739dd1de1a8 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -453,19 +453,20 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages) 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(); -- cgit v1.2.3