memory controller: soft limit interface

[safe/jmp/linux-2.6] / include / linux / res_counter.h

diff --git a/include/linux/res_counter.h b/include/linux/res_counter.h
index 511f42f..fcb9884 100644 (file)
--- a/include/linux/res_counter.h
+++ b/include/linux/res_counter.h
@@ -35,6 +35,10 @@ struct res_counter {
         */
        unsigned long long limit;
        /*
+        * the limit that usage can be exceed
+        */
+       unsigned long long soft_limit;
+       /*
         * the number of unsuccessful attempts to consume the resource
         */
        unsigned long long failcnt;
@@ -87,6 +91,7 @@ enum {
        RES_MAX_USAGE,
        RES_LIMIT,
        RES_FAILCNT,
+       RES_SOFT_LIMIT,
 };
 
 /*
@@ -132,6 +137,36 @@ static inline bool res_counter_limit_check_locked(struct res_counter *cnt)
        return false;
 }
 
+static inline bool res_counter_soft_limit_check_locked(struct res_counter *cnt)
+{
+       if (cnt->usage < cnt->soft_limit)
+               return true;
+
+       return false;
+}
+
+/**
+ * Get the difference between the usage and the soft limit
+ * @cnt: The counter
+ *
+ * Returns 0 if usage is less than or equal to soft limit
+ * The difference between usage and soft limit, otherwise.
+ */
+static inline unsigned long long
+res_counter_soft_limit_excess(struct res_counter *cnt)
+{
+       unsigned long long excess;
+       unsigned long flags;
+
+       spin_lock_irqsave(&cnt->lock, flags);
+       if (cnt->usage <= cnt->soft_limit)
+               excess = 0;
+       else
+               excess = cnt->usage - cnt->soft_limit;
+       spin_unlock_irqrestore(&cnt->lock, flags);
+       return excess;
+}
+
 /*
  * Helper function to detect if the cgroup is within it's limit or
  * not. It's currently called from cgroup_rss_prepare()
@@ -147,6 +182,17 @@ static inline bool res_counter_check_under_limit(struct res_counter *cnt)
        return ret;
 }
 
+static inline bool res_counter_check_under_soft_limit(struct res_counter *cnt)
+{
+       bool ret;
+       unsigned long flags;
+
+       spin_lock_irqsave(&cnt->lock, flags);
+       ret = res_counter_soft_limit_check_locked(cnt);
+       spin_unlock_irqrestore(&cnt->lock, flags);
+       return ret;
+}
+
 static inline void res_counter_reset_max(struct res_counter *cnt)
 {
        unsigned long flags;
@@ -180,4 +226,16 @@ static inline int res_counter_set_limit(struct res_counter *cnt,
        return ret;
 }
 
+static inline int
+res_counter_set_soft_limit(struct res_counter *cnt,
+                               unsigned long long soft_limit)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&cnt->lock, flags);
+       cnt->soft_limit = soft_limit;
+       spin_unlock_irqrestore(&cnt->lock, flags);
+       return 0;
+}
+
 #endif