From: Tang Chen <tangchen@xxxxxxxxxxxxxx>
Subject: 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 <tangchen@xxxxxxxxxxxxxx>
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> [3.16+]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
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 -puN include/linux/bootmem.h~mem-hotplug-reset-node-managed-pages-when-hot-adding-a-new-pgdat include/linux/bootmem.h
--- a/include/linux/bootmem.h~mem-hotplug-reset-node-managed-pages-when-hot-adding-a-new-pgdat
+++ a/include/linux/bootmem.h
@@ -46,6 +46,7 @@ extern unsigned long init_bootmem_node(p
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 -puN mm/bootmem.c~mem-hotplug-reset-node-managed-pages-when-hot-adding-a-new-pgdat mm/bootmem.c
--- a/mm/bootmem.c~mem-hotplug-reset-node-managed-pages-when-hot-adding-a-new-pgdat
+++ a/mm/bootmem.c
@@ -243,13 +243,10 @@ static unsigned long __init free_all_boo
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_page
{
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 -puN mm/memory_hotplug.c~mem-hotplug-reset-node-managed-pages-when-hot-adding-a-new-pgdat mm/memory_hotplug.c
--- a/mm/memory_hotplug.c~mem-hotplug-reset-node-managed-pages-when-hot-adding-a-new-pgdat
+++ a/mm/memory_hotplug.c
@@ -31,6 +31,7 @@
#include <linux/stop_machine.h>
#include <linux/hugetlb.h>
#include <linux/memblock.h>
+#include <linux/bootmem.h>
#include <asm/tlbflush.h>
@@ -1096,6 +1097,14 @@ static pg_data_t __ref *hotadd_new_pgdat
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 -puN mm/nobootmem.c~mem-hotplug-reset-node-managed-pages-when-hot-adding-a-new-pgdat mm/nobootmem.c
--- a/mm/nobootmem.c~mem-hotplug-reset-node-managed-pages-when-hot-adding-a-new-pgdat
+++ a/mm/nobootmem.c
@@ -145,12 +145,10 @@ static unsigned long __init free_low_mem
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_page
{
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;
}
_
--
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