[PATCH 9/10] hugetlb: per node attributes -- handle memory hot plug Against: 2.6.31-mmotm-090925-1435 Register per node hstate attributes only for nodes with memory. 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: Lee Schermerhorn <lee.schermerhorn@xxxxxx> Documentation/vm/hugetlbpage.txt | 3 +- drivers/base/node.c | 53 +++++++++++++++++++++++++++++++++++---- 2 files changed, 50 insertions(+), 6 deletions(-) Index: linux-2.6.31-mmotm-090925-1435/drivers/base/node.c =================================================================== --- linux-2.6.31-mmotm-090925-1435.orig/drivers/base/node.c 2009-09-30 15:05:20.000000000 -0400 +++ linux-2.6.31-mmotm-090925-1435/drivers/base/node.c 2009-09-30 15:05:57.000000000 -0400 @@ -177,8 +177,8 @@ static SYSDEV_ATTR(distance, S_IRUGO, no /* * 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 __hugetl 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 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 Index: linux-2.6.31-mmotm-090925-1435/Documentation/vm/hugetlbpage.txt =================================================================== --- linux-2.6.31-mmotm-090925-1435.orig/Documentation/vm/hugetlbpage.txt 2009-09-30 15:05:31.000000000 -0400 +++ linux-2.6.31-mmotm-090925-1435/Documentation/vm/hugetlbpage.txt 2009-09-30 15:05:57.000000000 -0400 @@ -231,7 +231,8 @@ resulting effect on persistent huge page 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/ -- To unsubscribe from this list: send the line "unsubscribe linux-numa" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html