mm: memcontrol: simplify soft limit tree init code

- No need to test the node for N_MEMORY.  node_online() is enough for
  node fallback to work in slab, use NUMA_NO_NODE for everything else.

- Remove the BUG_ON() for allocation failure.  A NULL pointer crash is
  just as descriptive, and the absent return value check is obvious.

- Move local variables to the inner-most blocks.

- Point to the tree structure after its initialized, not before, it's
  just more logical that way.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 8 insertions, 9 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index fbf64e6f64e4..2efec685793b 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4509,24 +4509,23 @@ EXPORT_SYMBOL(parent_mem_cgroup);
 
 static void __init mem_cgroup_soft_limit_tree_init(void)
 {
-        struct mem_cgroup_tree_per_node *rtpn;
-        struct mem_cgroup_tree_per_zone *rtpz;
-        int tmp, node, zone;
+        int node;
 
         for_each_node(node) {
-                tmp = node;
-                if (!node_state(node, N_NORMAL_MEMORY))
-                        tmp = -1;
-                rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, tmp);
-                BUG_ON(!rtpn);
+                struct mem_cgroup_tree_per_node *rtpn;
+                int zone;
 
-                soft_limit_tree.rb_tree_per_node[node] = rtpn;
+                rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL,
+                                    node_online(node) ? node : NUMA_NO_NODE);
 
                 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
+                        struct mem_cgroup_tree_per_zone *rtpz;
+
                         rtpz = &rtpn->rb_tree_per_zone[zone];
                         rtpz->rb_root = RB_ROOT;
                         spin_lock_init(&rtpz->lock);
                 }
+                soft_limit_tree.rb_tree_per_node[node] = rtpn;
         }
 }