Display current tcp memory allocation in kmem cgroup

This patch introduces kmem.tcp.usage_in_bytes file, living in the
kmem_cgroup filesystem. It is a simple read-only file that displays the
amount of kernel memory currently consumed by the cgroup.

Signed-off-by: Glauber Costa <glommer@parallels.com>
Reviewed-by: Hiroyouki Kamezawa <kamezawa.hiroyu@jp.fujitsu.com>
CC: David S. Miller <davem@davemloft.net>
CC: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt
index 1c9779a..6922b6c 100644 (file)
--- a/Documentation/cgroups/memory.txt
+++ b/Documentation/cgroups/memory.txt
@@ -79,6 +79,7 @@ Brief summary of control files.
  memory.independent_kmem_limit  # select whether or not kernel memory limits are
                                   independent of user limits
  memory.kmem.tcp.limit_in_bytes  # set/show hard limit for tcp buf memory
+ memory.kmem.tcp.usage_in_bytes  # show current tcp buf memory allocation
 
 1. History
 

diff --git a/net/ipv4/tcp_memcontrol.c b/net/ipv4/tcp_memcontrol.c
index e353390..9481f23 100644 (file)
--- a/net/ipv4/tcp_memcontrol.c
+++ b/net/ipv4/tcp_memcontrol.c
@@ -17,6 +17,11 @@ static struct cftype tcp_files[] = {
                .read_u64 = tcp_cgroup_read,
                .private = RES_LIMIT,
        },
+       {
+               .name = "kmem.tcp.usage_in_bytes",
+               .read_u64 = tcp_cgroup_read,
+               .private = RES_USAGE,
+       },
 };
 
 static inline struct tcp_memcontrol *tcp_from_cgproto(struct cg_proto *cg_proto)
@@ -167,6 +172,19 @@ static u64 tcp_read_stat(struct mem_cgroup *memcg, int type, u64 default_val)
        return res_counter_read_u64(&tcp->tcp_memory_allocated, type);
 }
 
+static u64 tcp_read_usage(struct mem_cgroup *memcg)
+{
+       struct tcp_memcontrol *tcp;
+       struct cg_proto *cg_proto;
+
+       cg_proto = tcp_prot.proto_cgroup(memcg);
+       if (!cg_proto)
+               return atomic_long_read(&tcp_memory_allocated) << PAGE_SHIFT;
+
+       tcp = tcp_from_cgproto(cg_proto);
+       return res_counter_read_u64(&tcp->tcp_memory_allocated, RES_USAGE);
+}
+
 static u64 tcp_cgroup_read(struct cgroup *cont, struct cftype *cft)
 {
        struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
@@ -176,6 +194,9 @@ static u64 tcp_cgroup_read(struct cgroup *cont, struct cftype *cft)
        case RES_LIMIT:
                val = tcp_read_stat(memcg, RES_LIMIT, RESOURCE_MAX);
                break;
+       case RES_USAGE:
+               val = tcp_read_usage(memcg);
+               break;
        default:
                BUG();
        }