Commit f784a3f1 authored by Tang Chen's avatar Tang Chen Committed by Linus Torvalds
Browse files

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: default avatarTang Chen <tangchen@cn.fujitsu.com>
Signed-off-by: default avatarYasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: <stable@vger.kernel.org>	[3.16+]
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 57cbc87e

include/linux/bootmem.h

+1 −0
Original line number Diff line number Diff line
@@ -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,

mm/bootmem.c

+5 −4
Original line number Diff line number Diff line
@@ -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;

}

mm/memory_hotplug.c

+9 −0
Original line number Diff line number Diff line
@@ -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(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;

}

mm/nobootmem.c

+5 −3
Original line number Diff line number Diff line
@@ -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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