CIFS: Clarify SMB1 code for POSIX Lock

[linux-2.6-microblaze.git] / mm / memcontrol.c

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index f7a552e..4ee243c 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -78,6 +78,7 @@ struct mem_cgroup *root_mem_cgroup __read_mostly;
 
 /* Active memory cgroup to use from an interrupt context */
 DEFINE_PER_CPU(struct mem_cgroup *, int_active_memcg);
+EXPORT_PER_CPU_SYMBOL_GPL(int_active_memcg);
 
 /* Socket memory accounting disabled? */
 static bool cgroup_memory_nosocket;
@@ -897,13 +898,24 @@ struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
 }
 EXPORT_SYMBOL(mem_cgroup_from_task);
 
+static __always_inline struct mem_cgroup *active_memcg(void)
+{
+       if (in_interrupt())
+               return this_cpu_read(int_active_memcg);
+       else
+               return current->active_memcg;
+}
+
 /**
  * get_mem_cgroup_from_mm: Obtain a reference on given mm_struct's memcg.
  * @mm: mm from which memcg should be extracted. It can be NULL.
  *
- * Obtain a reference on mm->memcg and returns it if successful. Otherwise
- * root_mem_cgroup is returned. However if mem_cgroup is disabled, NULL is
- * returned.
+ * Obtain a reference on mm->memcg and returns it if successful. If mm
+ * is NULL, then the memcg is chosen as follows:
+ * 1) The active memcg, if set.
+ * 2) current->mm->memcg, if available
+ * 3) root memcg
+ * If mem_cgroup is disabled, NULL is returned.
  */
 struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm)
 {
@@ -921,8 +933,17 @@ struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm)
         * counting is disabled on the root level in the
         * cgroup core. See CSS_NO_REF.
         */
-       if (unlikely(!mm))
-               return root_mem_cgroup;
+       if (unlikely(!mm)) {
+               memcg = active_memcg();
+               if (unlikely(memcg)) {
+                       /* remote memcg must hold a ref */
+                       css_get(&memcg->css);
+                       return memcg;
+               }
+               mm = current->mm;
+               if (unlikely(!mm))
+                       return root_mem_cgroup;
+       }
 
        rcu_read_lock();
        do {
@@ -935,14 +956,6 @@ struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm)
 }
 EXPORT_SYMBOL(get_mem_cgroup_from_mm);
 
-static __always_inline struct mem_cgroup *active_memcg(void)
-{
-       if (in_interrupt())
-               return this_cpu_read(int_active_memcg);
-       else
-               return current->active_memcg;
-}
-
 static __always_inline bool memcg_kmem_bypass(void)
 {
        /* Allow remote memcg charging from any context. */
@@ -6711,7 +6724,8 @@ out:
  * @gfp_mask: reclaim mode
  *
  * Try to charge @page to the memcg that @mm belongs to, reclaiming
- * pages according to @gfp_mask if necessary.
+ * pages according to @gfp_mask if necessary. if @mm is NULL, try to
+ * charge to the active memcg.
  *
  * Do not use this for pages allocated for swapin.
  *