cpumask: convert node_to_cpumask_map[] to cpumask_var_t

Impact: reduce kernel memory usage when CONFIG_CPUMASK_OFFSTACK=y

Straightforward conversion: done for 32 and 64 bit kernels.
node_to_cpumask_map is now a cpumask_var_t array.

64-bit used to be a dynamic cpumask_t array, and 32-bit used to be a
static cpumask_t array.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

1 files changed, 12 insertions, 16 deletions

diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
index f3a19e939e80..429dc2d191fd 100644
--- a/arch/x86/mm/numa.c
+++ b/arch/x86/mm/numa.c
@@ -12,7 +12,7 @@
 /*
  * Which logical CPUs are on which nodes
  */
-cpumask_t *node_to_cpumask_map;
+cpumask_var_t node_to_cpumask_map[MAX_NUMNODES];
 EXPORT_SYMBOL(node_to_cpumask_map);
 
 /*
@@ -25,7 +25,6 @@ EXPORT_SYMBOL(node_to_cpumask_map);
 void __init setup_node_to_cpumask_map(void)
 {
         unsigned int node, num = 0;
-        cpumask_t *map;
 
         /* setup nr_node_ids if not done yet */
         if (nr_node_ids == MAX_NUMNODES) {
@@ -35,14 +34,11 @@ void __init setup_node_to_cpumask_map(void)
         }
 
         /* allocate the map */
-        map = alloc_bootmem_low(nr_node_ids * sizeof(cpumask_t));
-        DBG("node_to_cpumask_map at %p for %d nodes\n", map, nr_node_ids);
+        for (node = 0; node < nr_node_ids; node++)
+                alloc_bootmem_cpumask_var(&node_to_cpumask_map[node]);
 
-        pr_debug("Node to cpumask map at %p for %d nodes\n",
-                 map, nr_node_ids);
-
-        /* node_to_cpumask() will now work */
-        node_to_cpumask_map = map;
+        /* cpumask_of_node() will now work */
+        pr_debug("Node to cpumask map for %d nodes\n", nr_node_ids);
 }
 
 #ifdef CONFIG_DEBUG_PER_CPU_MAPS
@@ -51,13 +47,6 @@ void __init setup_node_to_cpumask_map(void)
  */
 const cpumask_t *cpumask_of_node(int node)
 {
-        if (node_to_cpumask_map == NULL) {
-                printk(KERN_WARNING
-                        "cpumask_of_node(%d): no node_to_cpumask_map!\n",
-                        node);
-                dump_stack();
-                return cpu_online_mask;
-        }
         if (node >= nr_node_ids) {
                 printk(KERN_WARNING
                         "cpumask_of_node(%d): node > nr_node_ids(%d)\n",
@@ -65,6 +54,13 @@ const cpumask_t *cpumask_of_node(int node)
                 dump_stack();
                 return cpu_none_mask;
         }
+        if (node_to_cpumask_map[node] == NULL) {
+                printk(KERN_WARNING
+                        "cpumask_of_node(%d): no node_to_cpumask_map!\n",
+                        node);
+                dump_stack();
+                return cpu_online_mask;
+        }
         return &node_to_cpumask_map[node];
 }
 EXPORT_SYMBOL(cpumask_of_node);