From f784a3f19613901ca4539a5b0eed3bdc700e6ee7 Mon Sep 17 00:00:00 2001 From: Tang Chen Date: Thu, 13 Nov 2014 15:19:39 -0800 Subject: [PATCH] mem-hotplug: reset node managed pages when hot-adding a new pgdat In free_area_init_core(), zone->managed_pages is set to an approximate value for lowmem, and will be adjusted when the bootmem allocator frees pages into the buddy system. But free_area_init_core() is also called by hotadd_new_pgdat() when hot-adding memory. As a result, zone->managed_pages of the newly added node's pgdat is set to an approximate value in the very beginning. Even if the memory on that node has node been onlined, /sys/device/system/node/nodeXXX/meminfo has wrong value: hot-add node2 (memory not onlined) cat /sys/device/system/node/node2/meminfo Node 2 MemTotal: 33554432 kB Node 2 MemFree: 0 kB Node 2 MemUsed: 33554432 kB Node 2 Active: 0 kB This patch fixes this problem by reset node managed pages to 0 after hot-adding a new node. 1. Move reset_managed_pages_done from reset_node_managed_pages() to reset_all_zones_managed_pages() 2. Make reset_node_managed_pages() non-static 3. Call reset_node_managed_pages() in hotadd_new_pgdat() after pgdat is initialized Signed-off-by: Tang Chen Signed-off-by: Yasuaki Ishimatsu Cc: [3.16+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/bootmem.h | 1 + mm/bootmem.c | 9 +++++---- mm/memory_hotplug.c | 9 +++++++++ mm/nobootmem.c | 8 +++++--- 4 files changed, 20 insertions(+), 7 deletions(-) diff --git a/include/linux/bootmem.h b/include/linux/bootmem.h index 4e2bd4c95b66..0995c2de8162 100644 --- a/include/linux/bootmem.h +++ b/include/linux/bootmem.h @@ -46,6 +46,7 @@ extern unsigned long init_bootmem_node(pg_data_t *pgdat, extern unsigned long init_bootmem(unsigned long addr, unsigned long memend); extern unsigned long free_all_bootmem(void); +extern void reset_node_managed_pages(pg_data_t *pgdat); extern void reset_all_zones_managed_pages(void); extern void free_bootmem_node(pg_data_t *pgdat, diff --git a/mm/bootmem.c b/mm/bootmem.c index 8a000cebb0d7..477be696511d 100644 --- a/mm/bootmem.c +++ b/mm/bootmem.c @@ -243,13 +243,10 @@ static unsigned long __init free_all_bootmem_core(bootmem_data_t *bdata) static int reset_managed_pages_done __initdata; -static inline void __init reset_node_managed_pages(pg_data_t *pgdat) +void reset_node_managed_pages(pg_data_t *pgdat) { struct zone *z; - if (reset_managed_pages_done) - return; - for (z = pgdat->node_zones; z < pgdat->node_zones + MAX_NR_ZONES; z++) z->managed_pages = 0; } @@ -258,8 +255,12 @@ void __init reset_all_zones_managed_pages(void) { struct pglist_data *pgdat; + if (reset_managed_pages_done) + return; + for_each_online_pgdat(pgdat) reset_node_managed_pages(pgdat); + reset_managed_pages_done = 1; } diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 252e1dbbed86..c5f7fe199a60 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -31,6 +31,7 @@ #include #include #include +#include #include @@ -1096,6 +1097,14 @@ static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start) build_all_zonelists(pgdat, NULL); mutex_unlock(&zonelists_mutex); + /* + * zone->managed_pages is set to an approximate value in + * free_area_init_core(), which will cause + * /sys/device/system/node/nodeX/meminfo has wrong data. + * So reset it to 0 before any memory is onlined. + */ + reset_node_managed_pages(pgdat); + return pgdat; } diff --git a/mm/nobootmem.c b/mm/nobootmem.c index 7c7ab32ee503..90b50468333e 100644 --- a/mm/nobootmem.c +++ b/mm/nobootmem.c @@ -145,12 +145,10 @@ static unsigned long __init free_low_memory_core_early(void) static int reset_managed_pages_done __initdata; -static inline void __init reset_node_managed_pages(pg_data_t *pgdat) +void reset_node_managed_pages(pg_data_t *pgdat) { struct zone *z; - if (reset_managed_pages_done) - return; for (z = pgdat->node_zones; z < pgdat->node_zones + MAX_NR_ZONES; z++) z->managed_pages = 0; } @@ -159,8 +157,12 @@ void __init reset_all_zones_managed_pages(void) { struct pglist_data *pgdat; + if (reset_managed_pages_done) + return; + for_each_online_pgdat(pgdat) reset_node_managed_pages(pgdat); + reset_managed_pages_done = 1; } -- 2.20.1