From 0bd854200873894a76f32603ff2c4c988ad6b5b5 Mon Sep 17 00:00:00 2001 From: Tang Chen Date: Thu, 13 Nov 2014 15:19:41 -0800 Subject: [PATCH] mem-hotplug: reset node present pages when hot-adding a new pgdat When memory is hot-added, all the memory is in offline state. So clear all zones' present_pages because they will be updated in online_pages() and offline_pages(). Otherwise, /proc/zoneinfo will corrupt: When the memory of node2 is offline: # cat /proc/zoneinfo ...... Node 2, zone Movable ...... spanned 8388608 present 8388608 managed 0 When we online memory on node2: # cat /proc/zoneinfo ...... Node 2, zone Movable ...... spanned 8388608 present 16777216 managed 8388608 Signed-off-by: Tang Chen Reviewed-by: Yasuaki Ishimatsu Cc: [3.16+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memory_hotplug.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index c5f7fe199a60..1bf4807cb21e 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1067,6 +1067,16 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_typ } #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */ +static void reset_node_present_pages(pg_data_t *pgdat) +{ + struct zone *z; + + for (z = pgdat->node_zones; z < pgdat->node_zones + MAX_NR_ZONES; z++) + z->present_pages = 0; + + pgdat->node_present_pages = 0; +} + /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */ static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start) { @@ -1105,6 +1115,13 @@ static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start) */ reset_node_managed_pages(pgdat); + /* + * When memory is hot-added, all the memory is in offline state. So + * clear all zones' present_pages because they will be updated in + * online_pages() and offline_pages(). + */ + reset_node_present_pages(pgdat); + return pgdat; }