[PATCH v9 4/9] tcp memory pressure controls

[Glauber Costa <glommer@parallels.com>]

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>
---
 Documentation/cgroups/memory.txt |    2 +
 include/linux/memcontrol.h       |    1 +
 include/net/sock.h               |    2 +
 include/net/tcp_memcontrol.h     |   17 +++++++++
 mm/memcontrol.c                  |   40 ++++++++++++++++++++-
 net/core/sock.c                  |   43 ++++++++++++++++++++--
 net/ipv4/Makefile                |    1 +
 net/ipv4/tcp_ipv4.c              |    9 ++++-
 net/ipv4/tcp_memcontrol.c        |   74 ++++++++++++++++++++++++++++++++++++++
 net/ipv6/tcp_ipv6.c              |    5 +++
 10 files changed, 189 insertions(+), 5 deletions(-)
 create mode 100644 include/net/tcp_memcontrol.h
 create mode 100644 net/ipv4/tcp_memcontrol.c

diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt
index 23a8dc5..687dea5 100644
--- a/Documentation/cgroups/memory.txt
+++ b/Documentation/cgroups/memory.txt
@@ -293,6 +293,8 @@ to trigger slab reclaim when those limits are reached.
 thresholds. The Memory Controller allows them to be controlled individually
 per cgroup, instead of globally.
 
+* tcp memory pressure: sockets memory pressure for the tcp protocol.
+
 3. User Interface
 
 0. Configuration
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index f15021b..1513994 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -86,6 +86,7 @@ extern struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p);
 extern struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm);
 
 extern struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg);
+extern struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont);
 
 static inline
 int mm_match_cgroup(const struct mm_struct *mm, const struct mem_cgroup *cgroup)
diff --git a/include/net/sock.h b/include/net/sock.h
index 6cbee80..1df44e2 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -64,6 +64,8 @@
 #include <net/dst.h>
 #include <net/checksum.h>
 
+int mem_cgroup_sockets_init(struct cgroup *cgrp, struct cgroup_subsys *ss);
+void mem_cgroup_sockets_destroy(struct cgroup *cgrp, struct cgroup_subsys *ss);
 /*
  * This structure really needs to be cleaned up.
  * Most of it is for TCP, and not used by any of
diff --git a/include/net/tcp_memcontrol.h b/include/net/tcp_memcontrol.h
new file mode 100644
index 0000000..5f5e158
--- /dev/null
+++ b/include/net/tcp_memcontrol.h
@@ -0,0 +1,17 @@
+#ifndef _TCP_MEMCG_H
+#define _TCP_MEMCG_H
+
+struct tcp_memcontrol {
+	struct cg_proto cg_proto;
+	/* per-cgroup tcp memory pressure knobs */
+	struct res_counter tcp_memory_allocated;
+	struct percpu_counter tcp_sockets_allocated;
+	/* those two are read-mostly, leave them at the end */
+	long tcp_prot_mem[3];
+	int tcp_memory_pressure;
+};
+
+struct cg_proto *tcp_proto_cgroup(struct mem_cgroup *memcg);
+int tcp_init_cgroup(struct cgroup *cgrp, struct cgroup_subsys *ss);
+void tcp_destroy_cgroup(struct cgroup *cgrp, struct cgroup_subsys *ss);
+#endif /* _TCP_MEMCG_H */
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 3de3901..7266202 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -50,6 +50,8 @@
 #include <linux/cpu.h>
 #include <linux/oom.h>
 #include "internal.h"
+#include <net/sock.h>
+#include <net/tcp_memcontrol.h>
 
 #include <asm/uaccess.h>
 
@@ -295,6 +297,10 @@ struct mem_cgroup {
 	 */
 	struct mem_cgroup_stat_cpu nocpu_base;
 	spinlock_t pcp_counter_lock;
+
+#ifdef CONFIG_INET
+	struct tcp_memcontrol tcp_mem;
+#endif
 };
 
 /* Stuffs for move charges at task migration. */
@@ -384,6 +390,7 @@ static void mem_cgroup_put(struct mem_cgroup *memcg);
 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
 #ifdef CONFIG_INET
 #include <net/sock.h>
+#include <net/ip.h>
 
 static bool mem_cgroup_is_root(struct mem_cgroup *memcg);
 void sock_update_memcg(struct sock *sk)
@@ -418,6 +425,15 @@ void sock_release_memcg(struct sock *sk)
 		mem_cgroup_put(memcg);
 	}
 }
+
+struct cg_proto *tcp_proto_cgroup(struct mem_cgroup *memcg)
+{
+	if (!memcg || mem_cgroup_is_root(memcg))
+		return NULL;
+
+	return &memcg->tcp_mem.cg_proto;
+}
+EXPORT_SYMBOL(tcp_proto_cgroup);
 #endif /* CONFIG_INET */
 #endif /* CONFIG_CGROUP_MEM_RES_CTLR_KMEM */
 
@@ -800,7 +816,7 @@ static void memcg_check_events(struct mem_cgroup *memcg, struct page *page)
 	preempt_enable();
 }
 
-static struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont)
+struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont)
 {
 	return container_of(cgroup_subsys_state(cont,
 				mem_cgroup_subsys_id), struct mem_cgroup,
@@ -4732,14 +4748,34 @@ static int register_kmem_files(struct cgroup *cont, struct cgroup_subsys *ss)
 
 	ret = cgroup_add_files(cont, ss, kmem_cgroup_files,
 			       ARRAY_SIZE(kmem_cgroup_files));
+
+	/*
+	 * Part of this would be better living in a separate allocation
+	 * function, leaving us with just the cgroup tree population work.
+	 * We, however, depend on state such as network's proto_list that
+	 * is only initialized after cgroup creation. I found the less
+	 * cumbersome way to deal with it to defer it all to populate time
+	 */
+	if (!ret)
+		ret = mem_cgroup_sockets_init(cont, ss);
 	return ret;
 };
 
+static void kmem_cgroup_destroy(struct cgroup_subsys *ss,
+				struct cgroup *cont)
+{
+	mem_cgroup_sockets_destroy(cont, ss);
+}
 #else
 static int register_kmem_files(struct cgroup *cont, struct cgroup_subsys *ss)
 {
 	return 0;
 }
+
+static void kmem_cgroup_destroy(struct cgroup_subsys *ss,
+				struct cgroup *cont)
+{
+}
 #endif
 
 static struct cftype mem_cgroup_files[] = {
@@ -5098,6 +5134,8 @@ static void mem_cgroup_destroy(struct cgroup_subsys *ss,
 {
 	struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
 
+	kmem_cgroup_destroy(ss, cont);
+
 	mem_cgroup_put(memcg);
 }
 
diff --git a/net/core/sock.c b/net/core/sock.c
index 02f32be..5de62d3 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -135,6 +135,46 @@
 #include <net/tcp.h>
 #endif
 
+static DEFINE_RWLOCK(proto_list_lock);
+static LIST_HEAD(proto_list);
+
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+int mem_cgroup_sockets_init(struct cgroup *cgrp, struct cgroup_subsys *ss)
+{
+	struct proto *proto;
+	int ret = 0;
+
+	read_lock(&proto_list_lock);
+	list_for_each_entry(proto, &proto_list, node) {
+		if (proto->init_cgroup) {
+			ret = proto->init_cgroup(cgrp, ss);
+			if (ret)
+				goto out;
+		}
+	}
+
+	read_unlock(&proto_list_lock);
+	return ret;
+out:
+	list_for_each_entry_continue_reverse(proto, &proto_list, node)
+		if (proto->destroy_cgroup)
+			proto->destroy_cgroup(cgrp, ss);
+	read_unlock(&proto_list_lock);
+	return ret;
+}
+
+void mem_cgroup_sockets_destroy(struct cgroup *cgrp, struct cgroup_subsys *ss)
+{
+	struct proto *proto;
+
+	read_lock(&proto_list_lock);
+	list_for_each_entry_reverse(proto, &proto_list, node)
+		if (proto->destroy_cgroup)
+			proto->destroy_cgroup(cgrp, ss);
+	read_unlock(&proto_list_lock);
+}
+#endif
+
 /*
  * Each address family might have different locking rules, so we have
  * one slock key per address family:
@@ -2258,9 +2298,6 @@ void sk_common_release(struct sock *sk)
 }
 EXPORT_SYMBOL(sk_common_release);
 
-static DEFINE_RWLOCK(proto_list_lock);
-static LIST_HEAD(proto_list);
-
 #ifdef CONFIG_PROC_FS
 #define PROTO_INUSE_NR	64	/* should be enough for the first time */
 struct prot_inuse {
diff --git a/net/ipv4/Makefile b/net/ipv4/Makefile
index f2dc69c..dc67a99 100644
--- a/net/ipv4/Makefile
+++ b/net/ipv4/Makefile
@@ -47,6 +47,7 @@ obj-$(CONFIG_TCP_CONG_SCALABLE) += tcp_scalable.o
 obj-$(CONFIG_TCP_CONG_LP) += tcp_lp.o
 obj-$(CONFIG_TCP_CONG_YEAH) += tcp_yeah.o
 obj-$(CONFIG_TCP_CONG_ILLINOIS) += tcp_illinois.o
+obj-$(CONFIG_CGROUP_MEM_RES_CTLR_KMEM) += tcp_memcontrol.o
 obj-$(CONFIG_NETLABEL) += cipso_ipv4.o
 
 obj-$(CONFIG_XFRM) += xfrm4_policy.o xfrm4_state.o xfrm4_input.o \
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index d1f4bf8..f70923e 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -73,6 +73,7 @@
 #include <net/xfrm.h>
 #include <net/netdma.h>
 #include <net/secure_seq.h>
+#include <net/tcp_memcontrol.h>
 
 #include <linux/inet.h>
 #include <linux/ipv6.h>
@@ -1915,6 +1916,7 @@ static int tcp_v4_init_sock(struct sock *sk)
 	sk->sk_rcvbuf = sysctl_tcp_rmem[1];
 
 	local_bh_disable();
+	sock_update_memcg(sk);
 	sk_sockets_allocated_inc(sk);
 	local_bh_enable();
 
@@ -1972,6 +1974,7 @@ void tcp_v4_destroy_sock(struct sock *sk)
 	}
 
 	sk_sockets_allocated_dec(sk);
+	sock_release_memcg(sk);
 }
 EXPORT_SYMBOL(tcp_v4_destroy_sock);
 
@@ -2632,10 +2635,14 @@ struct proto tcp_prot = {
 	.compat_setsockopt	= compat_tcp_setsockopt,
 	.compat_getsockopt	= compat_tcp_getsockopt,
 #endif
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+	.init_cgroup		= tcp_init_cgroup,
+	.destroy_cgroup		= tcp_destroy_cgroup,
+	.proto_cgroup		= tcp_proto_cgroup,
+#endif
 };
 EXPORT_SYMBOL(tcp_prot);
 
-
 static int __net_init tcp_sk_init(struct net *net)
 {
 	return inet_ctl_sock_create(&net->ipv4.tcp_sock,
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);
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index e666768..820ae82 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -62,6 +62,7 @@
 #include <net/netdma.h>
 #include <net/inet_common.h>
 #include <net/secure_seq.h>
+#include <net/tcp_memcontrol.h>
 
 #include <asm/uaccess.h>
 
@@ -1995,6 +1996,7 @@ static int tcp_v6_init_sock(struct sock *sk)
 	sk->sk_rcvbuf = sysctl_tcp_rmem[1];
 
 	local_bh_disable();
+	sock_update_memcg(sk);
 	sk_sockets_allocated_inc(sk);
 	local_bh_enable();
 
@@ -2228,6 +2230,9 @@ struct proto tcpv6_prot = {
 	.compat_setsockopt	= compat_tcp_setsockopt,
 	.compat_getsockopt	= compat_tcp_getsockopt,
 #endif
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+	.proto_cgroup		= tcp_proto_cgroup,
+#endif
 };
 
 static const struct inet6_protocol tcpv6_protocol = {
-- 
1.7.6.4

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