kernel-ark/net/ipv4/tcp_memcontrol.c
Daniel Borkmann 4731d011d6 net: tcp_memcontrol: minor: remove unused variable
Commit 10b96f7306 (``tcp_memcontrol: remove a redundant statement
in tcp_destroy_cgroup()'') says ``We read the value but make no use
of it.'', but forgot to remove the variable declaration as well. This
was a follow-up commit of 3f1346193 (``memcg: decrement static keys
at real destroy time'') that removed the read of variable 'val'.

This fixes therefore:

  CC      net/ipv4/tcp_memcontrol.o
net/ipv4/tcp_memcontrol.c: In function ‘tcp_destroy_cgroup’:
net/ipv4/tcp_memcontrol.c:67:6: warning: unused variable ‘val’ [-Wunused-variable]

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-04-14 15:41:49 -04:00

289 lines
7.1 KiB
C

#include <net/tcp.h>
#include <net/tcp_memcontrol.h>
#include <net/sock.h>
#include <net/ip.h>
#include <linux/nsproxy.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 mem_cgroup *memcg, 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 *parent = parent_mem_cgroup(memcg);
struct net *net = current->nsproxy->net_ns;
cg_proto = tcp_prot.proto_cgroup(memcg);
if (!cg_proto)
return 0;
tcp = tcp_from_cgproto(cg_proto);
tcp->tcp_prot_mem[0] = net->ipv4.sysctl_tcp_mem[0];
tcp->tcp_prot_mem[1] = net->ipv4.sysctl_tcp_mem[1];
tcp->tcp_prot_mem[2] = net->ipv4.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 mem_cgroup *memcg)
{
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);
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)
clear_bit(MEMCG_SOCK_ACTIVE, &cg_proto->flags);
else if (val != RESOURCE_MAX) {
/*
* The active bit needs to be written after the static_key
* update. This is what guarantees that the socket activation
* function is the last one to run. See sock_update_memcg() for
* details, and note that we don't mark any socket as belonging
* to this memcg until that flag is up.
*
* We need to do this, because static_keys will span multiple
* sites, but we can't control their order. If we mark a socket
* as accounted, but the accounting functions are not patched in
* yet, we'll lose accounting.
*
* We never race with the readers in sock_update_memcg(),
* because when this value change, the code to process it is not
* patched in yet.
*
* The activated bit is used to guarantee that no two writers
* will do the update in the same memcg. Without that, we can't
* properly shutdown the static key.
*/
if (!test_and_set_bit(MEMCG_SOCK_ACTIVATED, &cg_proto->flags))
static_key_slow_inc(&memcg_socket_limit_enabled);
set_bit(MEMCG_SOCK_ACTIVE, &cg_proto->flags);
}
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_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);
u64 val;
switch (cft->private) {
case RES_LIMIT:
val = tcp_read_stat(memcg, RES_LIMIT, RESOURCE_MAX);
break;
case RES_USAGE:
val = tcp_read_usage(memcg);
break;
case RES_FAILCNT:
case RES_MAX_USAGE:
val = tcp_read_stat(memcg, cft->private, 0);
break;
default:
BUG();
}
return val;
}
static int tcp_cgroup_reset(struct cgroup *cont, unsigned int event)
{
struct mem_cgroup *memcg;
struct tcp_memcontrol *tcp;
struct cg_proto *cg_proto;
memcg = mem_cgroup_from_cont(cont);
cg_proto = tcp_prot.proto_cgroup(memcg);
if (!cg_proto)
return 0;
tcp = tcp_from_cgproto(cg_proto);
switch (event) {
case RES_MAX_USAGE:
res_counter_reset_max(&tcp->tcp_memory_allocated);
break;
case RES_FAILCNT:
res_counter_reset_failcnt(&tcp->tcp_memory_allocated);
break;
}
return 0;
}
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;
}
static struct cftype tcp_files[] = {
{
.name = "kmem.tcp.limit_in_bytes",
.write_string = tcp_cgroup_write,
.read_u64 = tcp_cgroup_read,
.private = RES_LIMIT,
},
{
.name = "kmem.tcp.usage_in_bytes",
.read_u64 = tcp_cgroup_read,
.private = RES_USAGE,
},
{
.name = "kmem.tcp.failcnt",
.private = RES_FAILCNT,
.trigger = tcp_cgroup_reset,
.read_u64 = tcp_cgroup_read,
},
{
.name = "kmem.tcp.max_usage_in_bytes",
.private = RES_MAX_USAGE,
.trigger = tcp_cgroup_reset,
.read_u64 = tcp_cgroup_read,
},
{ } /* terminate */
};
static int __init tcp_memcontrol_init(void)
{
WARN_ON(cgroup_add_cftypes(&mem_cgroup_subsys, tcp_files));
return 0;
}
__initcall(tcp_memcontrol_init);