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Commit 0bd85420 authored by Tang Chen's avatar Tang Chen Committed by Linus Torvalds
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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: default avatarTang Chen <tangchen@cn.fujitsu.com>
Reviewed-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 f784a3f1

mm/memory_hotplug.c

+17 −0
Original line number Original line Diff line number Diff line
@@ -1067,6 +1067,16 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_typ 
}

}

#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */

#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 */

/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */

static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)

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);

	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;

	return pgdat;

}

}