From 3aaabe2342c36bf48567b88fa78b819eee14bb5e Mon Sep 17 00:00:00 2001 From: Glauber Costa Date: Sun, 11 Dec 2011 21:47:06 +0000 Subject: tcp buffer limitation: per-cgroup limit This patch uses the "tcp.limit_in_bytes" field of the kmem_cgroup to effectively control the amount of kernel memory pinned by a cgroup. This value is ignored in the root cgroup, and in all others, caps the value specified by the admin in the net namespaces' view of tcp_sysctl_mem. If namespaces are being used, the admin is allowed to set a value bigger than cgroup's maximum, the same way it is allowed to set pretty much unlimited values in a real box. Signed-off-by: Glauber Costa Reviewed-by: Hiroyouki Kamezawa CC: David S. Miller CC: Eric W. Biederman Signed-off-by: David S. Miller --- net/ipv4/tcp_memcontrol.c | 137 +++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 135 insertions(+), 2 deletions(-) (limited to 'net/ipv4/tcp_memcontrol.c') diff --git a/net/ipv4/tcp_memcontrol.c b/net/ipv4/tcp_memcontrol.c index bfb0c2b8df46..e3533903409d 100644 --- a/net/ipv4/tcp_memcontrol.c +++ b/net/ipv4/tcp_memcontrol.c @@ -6,6 +6,19 @@ #include #include +static u64 tcp_cgroup_read(struct cgroup *cont, struct cftype *cft); +static int tcp_cgroup_write(struct cgroup *cont, struct cftype *cft, + const char *buffer); + +static struct cftype tcp_files[] = { + { + .name = "kmem.tcp.limit_in_bytes", + .write_string = tcp_cgroup_write, + .read_u64 = tcp_cgroup_read, + .private = RES_LIMIT, + }, +}; + static inline struct tcp_memcontrol *tcp_from_cgproto(struct cg_proto *cg_proto) { return container_of(cg_proto, struct tcp_memcontrol, cg_proto); @@ -34,7 +47,7 @@ int tcp_init_cgroup(struct cgroup *cgrp, struct cgroup_subsys *ss) cg_proto = tcp_prot.proto_cgroup(memcg); if (!cg_proto) - return 0; + goto create_files; tcp = tcp_from_cgproto(cg_proto); @@ -57,7 +70,9 @@ int tcp_init_cgroup(struct cgroup *cgrp, struct cgroup_subsys *ss) cg_proto->sockets_allocated = &tcp->tcp_sockets_allocated; cg_proto->memcg = memcg; - return 0; +create_files: + return cgroup_add_files(cgrp, ss, tcp_files, + ARRAY_SIZE(tcp_files)); } EXPORT_SYMBOL(tcp_init_cgroup); @@ -66,6 +81,7 @@ 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; + u64 val; cg_proto = tcp_prot.proto_cgroup(memcg); if (!cg_proto) @@ -73,5 +89,122 @@ void tcp_destroy_cgroup(struct cgroup *cgrp, struct cgroup_subsys *ss) tcp = tcp_from_cgproto(cg_proto); percpu_counter_destroy(&tcp->tcp_sockets_allocated); + + val = res_counter_read_u64(&tcp->tcp_memory_allocated, RES_USAGE); + + if (val != RESOURCE_MAX) + jump_label_dec(&memcg_socket_limit_enabled); } EXPORT_SYMBOL(tcp_destroy_cgroup); + +static int tcp_update_limit(struct mem_cgroup *memcg, u64 val) +{ + struct net *net = current->nsproxy->net_ns; + struct tcp_memcontrol *tcp; + struct cg_proto *cg_proto; + u64 old_lim; + int i; + int ret; + + cg_proto = tcp_prot.proto_cgroup(memcg); + if (!cg_proto) + return -EINVAL; + + if (val > RESOURCE_MAX) + val = RESOURCE_MAX; + + tcp = tcp_from_cgproto(cg_proto); + + old_lim = res_counter_read_u64(&tcp->tcp_memory_allocated, RES_LIMIT); + ret = res_counter_set_limit(&tcp->tcp_memory_allocated, val); + if (ret) + return ret; + + for (i = 0; i < 3; i++) + tcp->tcp_prot_mem[i] = min_t(long, val >> PAGE_SHIFT, + net->ipv4.sysctl_tcp_mem[i]); + + if (val == RESOURCE_MAX && old_lim != RESOURCE_MAX) + jump_label_dec(&memcg_socket_limit_enabled); + else if (old_lim == RESOURCE_MAX && val != RESOURCE_MAX) + jump_label_inc(&memcg_socket_limit_enabled); + + return 0; +} + +static int tcp_cgroup_write(struct cgroup *cont, struct cftype *cft, + const char *buffer) +{ + struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); + unsigned long long val; + int ret = 0; + + switch (cft->private) { + case RES_LIMIT: + /* see memcontrol.c */ + ret = res_counter_memparse_write_strategy(buffer, &val); + if (ret) + break; + ret = tcp_update_limit(memcg, val); + break; + default: + ret = -EINVAL; + break; + } + return ret; +} + +static u64 tcp_read_stat(struct mem_cgroup *memcg, int type, u64 default_val) +{ + struct tcp_memcontrol *tcp; + struct cg_proto *cg_proto; + + cg_proto = tcp_prot.proto_cgroup(memcg); + if (!cg_proto) + return default_val; + + tcp = tcp_from_cgproto(cg_proto); + return res_counter_read_u64(&tcp->tcp_memory_allocated, type); +} + +static u64 tcp_cgroup_read(struct cgroup *cont, struct cftype *cft) +{ + struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); + u64 val; + + switch (cft->private) { + case RES_LIMIT: + val = tcp_read_stat(memcg, RES_LIMIT, RESOURCE_MAX); + break; + default: + BUG(); + } + return val; +} + +unsigned long long tcp_max_memory(const struct mem_cgroup *memcg) +{ + struct tcp_memcontrol *tcp; + struct cg_proto *cg_proto; + + cg_proto = tcp_prot.proto_cgroup((struct mem_cgroup *)memcg); + if (!cg_proto) + return 0; + + tcp = tcp_from_cgproto(cg_proto); + return res_counter_read_u64(&tcp->tcp_memory_allocated, RES_LIMIT); +} + +void tcp_prot_mem(struct mem_cgroup *memcg, long val, int idx) +{ + struct tcp_memcontrol *tcp; + struct cg_proto *cg_proto; + + cg_proto = tcp_prot.proto_cgroup(memcg); + if (!cg_proto) + return; + + tcp = tcp_from_cgproto(cg_proto); + + tcp->tcp_prot_mem[idx] = val; +} -- cgit v1.2.3-59-g8ed1b