memcgroup: add the max_usage member on the res_counter

This field is the maximal value of the usage one since the counter creation
(or since the latest reset).

To reset this to the usage value simply write anything to the appropriate
cgroup file.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 17 insertions, 0 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 49d80814798..350a14da652 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,