Re: [PATCH 1/2] mem-hotplug: Reset node managed pages when hot-adding a new pgdat.
On 2014/10/31 17:46, Tang Chen wrote:
> 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
> ---
> 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 4e2bd4c..0995c2d 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 8a000ce..477be69 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 29d8693..3ab01b2 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);
> +
I aggree with you, we should reset it before online pages.
Thanks,
Xishi Qiu
> return pgdat;
> }
>
> diff --git a/mm/nobootmem.c b/mm/nobootmem.c
> index 7c7ab32..90b5046 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;
> }
>
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[PATCH 1/2] 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
---
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 4e2bd4c..0995c2d 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 8a000ce..477be69 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 29d8693..3ab01b2 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 7c7ab32..90b5046 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;
}
--
1.8.3.1
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