memcg: fix oops in mem_cgroup_shrink_usage

[linux-2.6-omap-h63xx.git] / mm / memcontrol.c

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 0c035647d36abb6e9dba83544620f613cd2148e8..0f1f7a7374bade23cf0052719a349a97322c5af4 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -796,6 +796,8 @@ int mem_cgroup_shrink_usage(struct mm_struct *mm, gfp_t gfp_mask)
 
        if (mem_cgroup_subsys.disabled)
                return 0;
+       if (!mm)
+               return 0;
 
        rcu_read_lock();
        mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
@@ -812,6 +814,30 @@ int mem_cgroup_shrink_usage(struct mm_struct *mm, gfp_t gfp_mask)
        return 0;
 }
 
+int mem_cgroup_resize_limit(struct mem_cgroup *memcg, unsigned long long val)
+{
+
+       int retry_count = MEM_CGROUP_RECLAIM_RETRIES;
+       int progress;
+       int ret = 0;
+
+       while (res_counter_set_limit(&memcg->res, val)) {
+               if (signal_pending(current)) {
+                       ret = -EINTR;
+                       break;
+               }
+               if (!retry_count) {
+                       ret = -EBUSY;
+                       break;
+               }
+               progress = try_to_free_mem_cgroup_pages(memcg, GFP_KERNEL);
+               if (!progress)
+                       retry_count--;
+       }
+       return ret;
+}
+
+
 /*
  * This routine traverse page_cgroup in given list and drop them all.
  * *And* this routine doesn't reclaim page itself, just removes page_cgroup.
@@ -896,13 +922,29 @@ static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
        return res_counter_read_u64(&mem_cgroup_from_cont(cont)->res,
                                    cft->private);
 }
-
+/*
+ * The user of this function is...
+ * RES_LIMIT.
+ */
 static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
                            const char *buffer)
 {
-       return res_counter_write(&mem_cgroup_from_cont(cont)->res,
-                                cft->private, buffer,
-                                res_counter_memparse_write_strategy);
+       struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
+       unsigned long long val;
+       int ret;
+
+       switch (cft->private) {
+       case RES_LIMIT:
+               /* This function does all necessary parse...reuse it */
+               ret = res_counter_memparse_write_strategy(buffer, &val);
+               if (!ret)
+                       ret = mem_cgroup_resize_limit(memcg, val);
+               break;
+       default:
+               ret = -EINVAL; /* should be BUG() ? */
+               break;
+       }
+       return ret;
 }
 
 static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
@@ -1128,9 +1170,6 @@ static void mem_cgroup_move_task(struct cgroup_subsys *ss,
        mem = mem_cgroup_from_cont(cont);
        old_mem = mem_cgroup_from_cont(old_cont);
 
-       if (mem == old_mem)
-               goto out;
-
        /*
         * Only thread group leaders are allowed to migrate, the mm_struct is
         * in effect owned by the leader