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Commit 4faf8d95 authored by Lee Schermerhorn's avatar Lee Schermerhorn Committed by Linus Torvalds
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hugetlb: handle memory hot-plug events 



Register per node hstate attributes only for nodes with memory.  As
suggested by David Rientjes.

With Memory Hotplug, memory can be added to a memoryless node and a node
with memory can become memoryless.  Therefore, add a memory on/off-line
notifier callback to [un]register a node's attributes on transition
to/from memoryless state.

N.B.,  Only tested build, boot, libhugetlbfs regression.
       i.e., no memory hotplug testing.

Signed-off-by: default avatarLee Schermerhorn <lee.schermerhorn@hp.com>
Reviewed-by: default avatarAndi Kleen <andi@firstfloor.org>
Acked-by: default avatarDavid Rientjes <rientjes@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Nishanth Aravamudan <nacc@us.ibm.com>
Cc: Adam Litke <agl@us.ibm.com>
Cc: Andy Whitcroft <apw@canonical.com>
Cc: Eric Whitney <eric.whitney@hp.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 8fe23e05

Documentation/vm/hugetlbpage.txt

+2 −1
Original line number Diff line number Diff line
@@ -231,7 +231,8 @@ resulting effect on persistent huge page allocation is as follows: 
Per Node Hugepages Attributes



A subset of the contents of the root huge page control directory in sysfs,

described above, has been replicated under each "node" system device in:

described above, will be replicated under each the system device of each

NUMA node with memory in:



	/sys/devices/system/node/node[0-9]*/hugepages/

drivers/base/node.c

+48 −5
Original line number Diff line number Diff line
@@ -177,8 +177,8 @@ static SYSDEV_ATTR(distance, S_IRUGO, node_read_distance, NULL); 
/*

 * hugetlbfs per node attributes registration interface:

 * When/if hugetlb[fs] subsystem initializes [sometime after this module],

 * it will register its per node attributes for all nodes online at that

 * time.  It will also call register_hugetlbfs_with_node(), below, to

 * it will register its per node attributes for all online nodes with

 * memory.  It will also call register_hugetlbfs_with_node(), below, to

 * register its attribute registration functions with this node driver.

 * Once these hooks have been initialized, the node driver will call into

 * the hugetlb module to [un]register attributes for hot-plugged nodes.
@@ -188,7 +188,8 @@ static node_registration_func_t __hugetlb_unregister_node; 


static inline void hugetlb_register_node(struct node *node)

{

	if (__hugetlb_register_node)

	if (__hugetlb_register_node &&

			node_state(node->sysdev.id, N_HIGH_MEMORY))

		__hugetlb_register_node(node);

}
@@ -233,6 +234,7 @@ int register_node(struct node *node, int num, struct node *parent) 
		sysdev_create_file(&node->sysdev, &attr_distance);



		scan_unevictable_register_node(node);



		hugetlb_register_node(node);

	}

	return error;
@@ -254,7 +256,7 @@ void unregister_node(struct node *node) 
	sysdev_remove_file(&node->sysdev, &attr_distance);



	scan_unevictable_unregister_node(node);

	hugetlb_unregister_node(node);

	hugetlb_unregister_node(node);		/* no-op, if memoryless node */



	sysdev_unregister(&node->sysdev);

}
@@ -384,8 +386,45 @@ static int link_mem_sections(int nid) 
	}

	return err;

}



/*

 * Handle per node hstate attribute [un]registration on transistions

 * to/from memoryless state.

 */



static int node_memory_callback(struct notifier_block *self,

				unsigned long action, void *arg)

{

	struct memory_notify *mnb = arg;

	int nid = mnb->status_change_nid;



	switch (action) {

	case MEM_ONLINE:    /* memory successfully brought online */

		if (nid != NUMA_NO_NODE)

			hugetlb_register_node(&node_devices[nid]);

		break;

	case MEM_OFFLINE:   /* or offline */

		if (nid != NUMA_NO_NODE)

			hugetlb_unregister_node(&node_devices[nid]);

		break;

	case MEM_GOING_ONLINE:

	case MEM_GOING_OFFLINE:

	case MEM_CANCEL_ONLINE:

	case MEM_CANCEL_OFFLINE:

	default:

		break;

	}



	return NOTIFY_OK;

}

#else

static int link_mem_sections(int nid) { return 0; }



static inline int node_memory_callback(struct notifier_block *self,

				unsigned long action, void *arg)

{

	return NOTIFY_OK;

}

#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */



int register_one_node(int nid)
@@ -499,13 +538,17 @@ static int node_states_init(void) 
	return err;

}



#define NODE_CALLBACK_PRI	2	/* lower than SLAB */

static int __init register_node_type(void)

{

	int ret;



	ret = sysdev_class_register(&node_class);

	if (!ret)

	if (!ret) {

		ret = node_states_init();

		hotplug_memory_notifier(node_memory_callback,

					NODE_CALLBACK_PRI);

	}



	/*

	 * Note:  we're not going to unregister the node class if we fail