numa: convert static memory to dynamically allocated memory for per node device

We use a static array to store struct node.  In many cases, we don't have
too many nodes, and some memory will be unused.  Convert it to per-device
dynamically allocated memory.

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Jiang Liu <liuj97@gmail.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 22 insertions, 16 deletions

diff --git a/drivers/base/node.c b/drivers/base/node.c
index af1a177216f1..28216ce74b3d 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -306,7 +306,7 @@ void unregister_node(struct node *node)
         device_unregister(&node->dev);
 }
 
-struct node node_devices[MAX_NUMNODES];
+struct node *node_devices[MAX_NUMNODES];
 
 /*
  * register cpu under node
@@ -323,15 +323,15 @@ int register_cpu_under_node(unsigned int cpu, unsigned int nid)
         if (!obj)
                 return 0;
 
-        ret = sysfs_create_link(&node_devices[nid].dev.kobj,
+        ret = sysfs_create_link(&node_devices[nid]->dev.kobj,
                                 &obj->kobj,
                                 kobject_name(&obj->kobj));
         if (ret)
                 return ret;
 
         return sysfs_create_link(&obj->kobj,
-                                 &node_devices[nid].dev.kobj,
-                                 kobject_name(&node_devices[nid].dev.kobj));
+                                 &node_devices[nid]->dev.kobj,
+                                 kobject_name(&node_devices[nid]->dev.kobj));
 }
 
 int unregister_cpu_under_node(unsigned int cpu, unsigned int nid)
@@ -345,10 +345,10 @@ int unregister_cpu_under_node(unsigned int cpu, unsigned int nid)
         if (!obj)
                 return 0;
 
-        sysfs_remove_link(&node_devices[nid].dev.kobj,
+        sysfs_remove_link(&node_devices[nid]->dev.kobj,
                           kobject_name(&obj->kobj));
         sysfs_remove_link(&obj->kobj,
-                          kobject_name(&node_devices[nid].dev.kobj));
+                          kobject_name(&node_devices[nid]->dev.kobj));
 
         return 0;
 }
@@ -390,15 +390,15 @@ int register_mem_sect_under_node(struct memory_block *mem_blk, int nid)
                         continue;
                 if (page_nid != nid)
                         continue;
-                ret = sysfs_create_link_nowarn(&node_devices[nid].dev.kobj,
+                ret = sysfs_create_link_nowarn(&node_devices[nid]->dev.kobj,
                                         &mem_blk->dev.kobj,
                                         kobject_name(&mem_blk->dev.kobj));
                 if (ret)
                         return ret;
 
                 return sysfs_create_link_nowarn(&mem_blk->dev.kobj,
-                                &node_devices[nid].dev.kobj,
-                                kobject_name(&node_devices[nid].dev.kobj));
+                                &node_devices[nid]->dev.kobj,
+                                kobject_name(&node_devices[nid]->dev.kobj));
         }
         /* mem section does not span the specified node */
         return 0;
@@ -431,10 +431,10 @@ int unregister_mem_sect_under_nodes(struct memory_block *mem_blk,
                         continue;
                 if (node_test_and_set(nid, *unlinked_nodes))
                         continue;
-                sysfs_remove_link(&node_devices[nid].dev.kobj,
+                sysfs_remove_link(&node_devices[nid]->dev.kobj,
                          kobject_name(&mem_blk->dev.kobj));
                 sysfs_remove_link(&mem_blk->dev.kobj,
-                         kobject_name(&node_devices[nid].dev.kobj));
+                         kobject_name(&node_devices[nid]->dev.kobj));
         }
         NODEMASK_FREE(unlinked_nodes);
         return 0;
@@ -500,7 +500,7 @@ static void node_hugetlb_work(struct work_struct *work)
 
 static void init_node_hugetlb_work(int nid)
 {
-        INIT_WORK(&node_devices[nid].node_work, node_hugetlb_work);
+        INIT_WORK(&node_devices[nid]->node_work, node_hugetlb_work);
 }
 
 static int node_memory_callback(struct notifier_block *self,
@@ -517,7 +517,7 @@ static int node_memory_callback(struct notifier_block *self,
                  * when transitioning to/from memoryless state.
                  */
                 if (nid != NUMA_NO_NODE)
-                        schedule_work(&node_devices[nid].node_work);
+                        schedule_work(&node_devices[nid]->node_work);
                 break;
 
         case MEM_GOING_ONLINE:
@@ -558,9 +558,13 @@ int register_one_node(int nid)
                 struct node *parent = NULL;
 
                 if (p_node != nid)
-                        parent = &node_devices[p_node];
+                        parent = node_devices[p_node];
 
-                error = register_node(&node_devices[nid], nid, parent);
+                node_devices[nid] = kzalloc(sizeof(struct node), GFP_KERNEL);
+                if (!node_devices[nid])
+                        return -ENOMEM;
+
+                error = register_node(node_devices[nid], nid, parent);
 
                 /* link cpu under this node */
                 for_each_present_cpu(cpu) {
@@ -581,7 +585,9 @@ int register_one_node(int nid)
 
 void unregister_one_node(int nid)
 {
-        unregister_node(&node_devices[nid]);
+        unregister_node(node_devices[nid]);
+        kfree(node_devices[nid]);
+        node_devices[nid] = NULL;
 }
 
 /*