3 files changed, 35 insertions, 0 deletions

diff --git a/include/linux/res_counter.h b/include/linux/res_counter.h
index 8cb1ecd420a9..df8085acba16 100644
--- a/include/linux/res_counter.h
+++ b/include/linux/res_counter.h
@@ -25,6 +25,10 @@ struct res_counter {
          */
         unsigned long long usage;
         /*
+         * the maximal value of the usage from the counter creation
+         */
+        unsigned long long max_usage;
+        /*
          * the limit that usage cannot exceed
          */
         unsigned long long limit;
@@ -67,6 +71,7 @@ ssize_t res_counter_write(struct res_counter *counter, int member,
 
 enum {
         RES_USAGE,
+        RES_MAX_USAGE,
         RES_LIMIT,
         RES_FAILCNT,
 };
@@ -127,4 +132,13 @@ static inline bool res_counter_check_under_limit(struct res_counter *cnt)
         return ret;
 }
 
+static inline void res_counter_reset_max(struct res_counter *cnt)
+{
+        unsigned long flags;
+
+        spin_lock_irqsave(&cnt->lock, flags);
+        cnt->max_usage = cnt->usage;
+        spin_unlock_irqrestore(&cnt->lock, flags);
+}
+
 #endif
diff --git a/kernel/res_counter.c b/kernel/res_counter.c
index 70587657dda3..d3c61b4ebef2 100644
--- a/kernel/res_counter.c
+++ b/kernel/res_counter.c
@@ -28,6 +28,8 @@ int res_counter_charge_locked(struct res_counter *counter, unsigned long val)
         }
 
         counter->usage += val;
+        if (counter->usage > counter->max_usage)
+                counter->max_usage = counter->usage;
         return 0;
 }
 
@@ -66,6 +68,8 @@ res_counter_member(struct res_counter *counter, int member)
         switch (member) {
         case RES_USAGE:
                 return &counter->usage;
+        case RES_MAX_USAGE:
+                return &counter->max_usage;
         case RES_LIMIT:
                 return &counter->limit;
         case RES_FAILCNT:
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 49d80814798b..350a14da6525 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -855,6 +855,17 @@ static ssize_t mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
                                 mem_cgroup_write_strategy);
 }
 
+static ssize_t mem_cgroup_max_reset(struct cgroup *cont, struct cftype *cft,
+                                struct file *file, const char __user *userbuf,
+                                size_t nbytes, loff_t *ppos)
+{
+        struct mem_cgroup *mem;
+
+        mem = mem_cgroup_from_cont(cont);
+        res_counter_reset_max(&mem->res);
+        return nbytes;
+}
+
 static ssize_t mem_force_empty_write(struct cgroup *cont,
                                 struct cftype *cft, struct file *file,
                                 const char __user *userbuf,
@@ -910,6 +921,12 @@ static struct cftype mem_cgroup_files[] = {
                 .read_u64 = mem_cgroup_read,
         },
         {
+                .name = "max_usage_in_bytes",
+                .private = RES_MAX_USAGE,
+                .write = mem_cgroup_max_reset,
+                .read_u64 = mem_cgroup_read,
+        },
+        {
                 .name = "limit_in_bytes",
                 .private = RES_LIMIT,
                 .write = mem_cgroup_write,