tcp memory pressure controls

This patch introduces memory pressure controls for the tcp
protocol. It uses the generic socket memory pressure code
introduced in earlier patches, and fills in the
necessary data in cg_proto struct.

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

1 files changed, 74 insertions, 0 deletions

diff --git a/net/ipv4/tcp_memcontrol.c b/net/ipv4/tcp_memcontrol.c
new file mode 100644
index 0000000..4a68d2c
--- /dev/null
+++ b/net/ipv4/tcp_memcontrol.c
@@ -0,0 +1,74 @@
+#include <net/tcp.h>
+#include <net/tcp_memcontrol.h>
+#include <net/sock.h>
+#include <linux/memcontrol.h>
+#include <linux/module.h>
+
+static inline struct tcp_memcontrol *tcp_from_cgproto(struct cg_proto *cg_proto)
+{
+	return container_of(cg_proto, struct tcp_memcontrol, cg_proto);
+}
+
+static void memcg_tcp_enter_memory_pressure(struct sock *sk)
+{
+	if (!sk->sk_cgrp->memory_pressure)
+		*sk->sk_cgrp->memory_pressure = 1;
+}
+EXPORT_SYMBOL(memcg_tcp_enter_memory_pressure);
+
+int tcp_init_cgroup(struct cgroup *cgrp, struct cgroup_subsys *ss)
+{
+	/*
+	 * The root cgroup does not use res_counters, but rather,
+	 * rely on the data already collected by the network
+	 * subsystem
+	 */
+	struct res_counter *res_parent = NULL;
+	struct cg_proto *cg_proto, *parent_cg;
+	struct tcp_memcontrol *tcp;
+	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
+	struct mem_cgroup *parent = parent_mem_cgroup(memcg);
+
+	cg_proto = tcp_prot.proto_cgroup(memcg);
+	if (!cg_proto)
+		return 0;
+
+	tcp = tcp_from_cgproto(cg_proto);
+
+	tcp->tcp_prot_mem[0] = sysctl_tcp_mem[0];
+	tcp->tcp_prot_mem[1] = sysctl_tcp_mem[1];
+	tcp->tcp_prot_mem[2] = sysctl_tcp_mem[2];
+	tcp->tcp_memory_pressure = 0;
+
+	parent_cg = tcp_prot.proto_cgroup(parent);
+	if (parent_cg)
+		res_parent = parent_cg->memory_allocated;
+
+	res_counter_init(&tcp->tcp_memory_allocated, res_parent);
+	percpu_counter_init(&tcp->tcp_sockets_allocated, 0);
+
+	cg_proto->enter_memory_pressure = memcg_tcp_enter_memory_pressure;
+	cg_proto->memory_pressure = &tcp->tcp_memory_pressure;
+	cg_proto->sysctl_mem = tcp->tcp_prot_mem;
+	cg_proto->memory_allocated = &tcp->tcp_memory_allocated;
+	cg_proto->sockets_allocated = &tcp->tcp_sockets_allocated;
+	cg_proto->memcg = memcg;
+
+	return 0;
+}
+EXPORT_SYMBOL(tcp_init_cgroup);
+
+void tcp_destroy_cgroup(struct cgroup *cgrp, struct cgroup_subsys *ss)
+{
+	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
+	struct cg_proto *cg_proto;
+	struct tcp_memcontrol *tcp;
+
+	cg_proto = tcp_prot.proto_cgroup(memcg);
+	if (!cg_proto)
+		return;
+
+	tcp = tcp_from_cgproto(cg_proto);
+	percpu_counter_destroy(&tcp->tcp_sockets_allocated);
+}
+EXPORT_SYMBOL(tcp_destroy_cgroup);