Merge branch 'akpm' (fixes from Andrew Morton)

Merge fixes from Andrew Morton:
 "5 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  mm: page_alloc: fix zone allocation fairness on UP
  perf: fix perf bug in fork()
  MAINTAINERS: change git URL for mpc5xxx tree
  mm: memcontrol: do not iterate uninitialized memcgs
  ocfs2/dlm: should put mle when goto kill in dlm_assert_master_handler

2 files changed, 34 insertions, 9 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 085dc6d2f876..28928ce9b07f 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -292,6 +292,9 @@ struct mem_cgroup {
         /* vmpressure notifications */
         struct vmpressure vmpressure;
 
+        /* css_online() has been completed */
+        int initialized;
+
         /*
          * the counter to account for mem+swap usage.
          */
@@ -1099,10 +1102,21 @@ skip_node:
          * skipping css reference should be safe.
          */
         if (next_css) {
-                if ((next_css == &root->css) ||
-                    ((next_css->flags & CSS_ONLINE) &&
-                     css_tryget_online(next_css)))
-                        return mem_cgroup_from_css(next_css);
+                struct mem_cgroup *memcg = mem_cgroup_from_css(next_css);
+
+                if (next_css == &root->css)
+                        return memcg;
+
+                if (css_tryget_online(next_css)) {
+                        /*
+                         * Make sure the memcg is initialized:
+                         * mem_cgroup_css_online() orders the the
+                         * initialization against setting the flag.
+                         */
+                        if (smp_load_acquire(&memcg->initialized))
+                                return memcg;
+                        css_put(next_css);
+                }
 
                 prev_css = next_css;
                 goto skip_node;
@@ -5549,6 +5563,7 @@ mem_cgroup_css_online(struct cgroup_subsys_state *css)
 {
         struct mem_cgroup *memcg = mem_cgroup_from_css(css);
         struct mem_cgroup *parent = mem_cgroup_from_css(css->parent);
+        int ret;
 
         if (css->id > MEM_CGROUP_ID_MAX)
                 return -ENOSPC;
@@ -5585,7 +5600,18 @@ mem_cgroup_css_online(struct cgroup_subsys_state *css)
         }
         mutex_unlock(&memcg_create_mutex);
 
-        return memcg_init_kmem(memcg, &memory_cgrp_subsys);
+        ret = memcg_init_kmem(memcg, &memory_cgrp_subsys);
+        if (ret)
+                return ret;
+
+        /*
+         * Make sure the memcg is initialized: mem_cgroup_iter()
+         * orders reading memcg->initialized against its callers
+         * reading the memcg members.
+         */
+        smp_store_release(&memcg->initialized, 1);
+
+        return 0;
 }
 
 /*
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 18cee0d4c8a2..eee961958021 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1612,7 +1612,7 @@ again:
         }
 
         __mod_zone_page_state(zone, NR_ALLOC_BATCH, -(1 << order));
-        if (zone_page_state(zone, NR_ALLOC_BATCH) == 0 &&
+        if (atomic_long_read(&zone->vm_stat[NR_ALLOC_BATCH]) <= 0 &&
             !zone_is_fair_depleted(zone))
                 zone_set_flag(zone, ZONE_FAIR_DEPLETED);
 
@@ -5701,9 +5701,8 @@ static void __setup_per_zone_wmarks(void)
                 zone->watermark[WMARK_HIGH] = min_wmark_pages(zone) + (tmp >> 1);
 
                 __mod_zone_page_state(zone, NR_ALLOC_BATCH,
-                                      high_wmark_pages(zone) -
-                                      low_wmark_pages(zone) -
-                                      zone_page_state(zone, NR_ALLOC_BATCH));
+                        high_wmark_pages(zone) - low_wmark_pages(zone) -
+                        atomic_long_read(&zone->vm_stat[NR_ALLOC_BATCH]));
 
                 setup_zone_migrate_reserve(zone);
                 spin_unlock_irqrestore(&zone->lock, flags);