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4731d011d6
Commit10b96f7306
(``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 of3f1346193
(``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>
288 lines
7.1 KiB
C
288 lines
7.1 KiB
C
#include <net/tcp.h>
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#include <net/tcp_memcontrol.h>
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#include <net/sock.h>
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#include <net/ip.h>
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#include <linux/nsproxy.h>
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#include <linux/memcontrol.h>
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#include <linux/module.h>
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static inline struct tcp_memcontrol *tcp_from_cgproto(struct cg_proto *cg_proto)
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{
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return container_of(cg_proto, struct tcp_memcontrol, cg_proto);
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}
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static void memcg_tcp_enter_memory_pressure(struct sock *sk)
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{
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if (sk->sk_cgrp->memory_pressure)
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*sk->sk_cgrp->memory_pressure = 1;
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}
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EXPORT_SYMBOL(memcg_tcp_enter_memory_pressure);
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int tcp_init_cgroup(struct mem_cgroup *memcg, struct cgroup_subsys *ss)
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{
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/*
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* The root cgroup does not use res_counters, but rather,
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* rely on the data already collected by the network
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* subsystem
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*/
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struct res_counter *res_parent = NULL;
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struct cg_proto *cg_proto, *parent_cg;
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struct tcp_memcontrol *tcp;
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struct mem_cgroup *parent = parent_mem_cgroup(memcg);
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struct net *net = current->nsproxy->net_ns;
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cg_proto = tcp_prot.proto_cgroup(memcg);
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if (!cg_proto)
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return 0;
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tcp = tcp_from_cgproto(cg_proto);
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tcp->tcp_prot_mem[0] = net->ipv4.sysctl_tcp_mem[0];
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tcp->tcp_prot_mem[1] = net->ipv4.sysctl_tcp_mem[1];
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tcp->tcp_prot_mem[2] = net->ipv4.sysctl_tcp_mem[2];
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tcp->tcp_memory_pressure = 0;
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parent_cg = tcp_prot.proto_cgroup(parent);
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if (parent_cg)
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res_parent = parent_cg->memory_allocated;
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res_counter_init(&tcp->tcp_memory_allocated, res_parent);
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percpu_counter_init(&tcp->tcp_sockets_allocated, 0);
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cg_proto->enter_memory_pressure = memcg_tcp_enter_memory_pressure;
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cg_proto->memory_pressure = &tcp->tcp_memory_pressure;
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cg_proto->sysctl_mem = tcp->tcp_prot_mem;
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cg_proto->memory_allocated = &tcp->tcp_memory_allocated;
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cg_proto->sockets_allocated = &tcp->tcp_sockets_allocated;
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cg_proto->memcg = memcg;
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return 0;
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}
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EXPORT_SYMBOL(tcp_init_cgroup);
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void tcp_destroy_cgroup(struct mem_cgroup *memcg)
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{
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struct cg_proto *cg_proto;
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struct tcp_memcontrol *tcp;
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cg_proto = tcp_prot.proto_cgroup(memcg);
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if (!cg_proto)
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return;
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tcp = tcp_from_cgproto(cg_proto);
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percpu_counter_destroy(&tcp->tcp_sockets_allocated);
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}
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EXPORT_SYMBOL(tcp_destroy_cgroup);
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static int tcp_update_limit(struct mem_cgroup *memcg, u64 val)
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{
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struct net *net = current->nsproxy->net_ns;
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struct tcp_memcontrol *tcp;
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struct cg_proto *cg_proto;
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u64 old_lim;
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int i;
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int ret;
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cg_proto = tcp_prot.proto_cgroup(memcg);
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if (!cg_proto)
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return -EINVAL;
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if (val > RESOURCE_MAX)
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val = RESOURCE_MAX;
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tcp = tcp_from_cgproto(cg_proto);
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old_lim = res_counter_read_u64(&tcp->tcp_memory_allocated, RES_LIMIT);
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ret = res_counter_set_limit(&tcp->tcp_memory_allocated, val);
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if (ret)
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return ret;
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for (i = 0; i < 3; i++)
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tcp->tcp_prot_mem[i] = min_t(long, val >> PAGE_SHIFT,
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net->ipv4.sysctl_tcp_mem[i]);
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if (val == RESOURCE_MAX)
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clear_bit(MEMCG_SOCK_ACTIVE, &cg_proto->flags);
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else if (val != RESOURCE_MAX) {
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/*
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* The active bit needs to be written after the static_key
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* update. This is what guarantees that the socket activation
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* function is the last one to run. See sock_update_memcg() for
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* details, and note that we don't mark any socket as belonging
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* to this memcg until that flag is up.
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*
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* We need to do this, because static_keys will span multiple
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* sites, but we can't control their order. If we mark a socket
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* as accounted, but the accounting functions are not patched in
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* yet, we'll lose accounting.
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*
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* We never race with the readers in sock_update_memcg(),
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* because when this value change, the code to process it is not
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* patched in yet.
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*
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* The activated bit is used to guarantee that no two writers
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* will do the update in the same memcg. Without that, we can't
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* properly shutdown the static key.
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*/
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if (!test_and_set_bit(MEMCG_SOCK_ACTIVATED, &cg_proto->flags))
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static_key_slow_inc(&memcg_socket_limit_enabled);
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set_bit(MEMCG_SOCK_ACTIVE, &cg_proto->flags);
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}
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return 0;
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}
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static int tcp_cgroup_write(struct cgroup *cont, struct cftype *cft,
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const char *buffer)
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{
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struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
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unsigned long long val;
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int ret = 0;
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switch (cft->private) {
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case RES_LIMIT:
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/* see memcontrol.c */
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ret = res_counter_memparse_write_strategy(buffer, &val);
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if (ret)
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break;
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ret = tcp_update_limit(memcg, val);
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break;
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default:
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ret = -EINVAL;
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break;
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}
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return ret;
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}
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static u64 tcp_read_stat(struct mem_cgroup *memcg, int type, u64 default_val)
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{
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struct tcp_memcontrol *tcp;
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struct cg_proto *cg_proto;
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cg_proto = tcp_prot.proto_cgroup(memcg);
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if (!cg_proto)
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return default_val;
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tcp = tcp_from_cgproto(cg_proto);
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return res_counter_read_u64(&tcp->tcp_memory_allocated, type);
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}
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static u64 tcp_read_usage(struct mem_cgroup *memcg)
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{
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struct tcp_memcontrol *tcp;
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struct cg_proto *cg_proto;
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cg_proto = tcp_prot.proto_cgroup(memcg);
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if (!cg_proto)
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return atomic_long_read(&tcp_memory_allocated) << PAGE_SHIFT;
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tcp = tcp_from_cgproto(cg_proto);
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return res_counter_read_u64(&tcp->tcp_memory_allocated, RES_USAGE);
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}
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static u64 tcp_cgroup_read(struct cgroup *cont, struct cftype *cft)
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{
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struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
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u64 val;
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switch (cft->private) {
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case RES_LIMIT:
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val = tcp_read_stat(memcg, RES_LIMIT, RESOURCE_MAX);
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break;
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case RES_USAGE:
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val = tcp_read_usage(memcg);
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break;
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case RES_FAILCNT:
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case RES_MAX_USAGE:
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val = tcp_read_stat(memcg, cft->private, 0);
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break;
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default:
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BUG();
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}
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return val;
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}
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static int tcp_cgroup_reset(struct cgroup *cont, unsigned int event)
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{
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struct mem_cgroup *memcg;
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struct tcp_memcontrol *tcp;
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struct cg_proto *cg_proto;
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memcg = mem_cgroup_from_cont(cont);
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cg_proto = tcp_prot.proto_cgroup(memcg);
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if (!cg_proto)
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return 0;
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tcp = tcp_from_cgproto(cg_proto);
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switch (event) {
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case RES_MAX_USAGE:
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res_counter_reset_max(&tcp->tcp_memory_allocated);
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break;
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case RES_FAILCNT:
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res_counter_reset_failcnt(&tcp->tcp_memory_allocated);
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break;
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}
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return 0;
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}
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unsigned long long tcp_max_memory(const struct mem_cgroup *memcg)
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{
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struct tcp_memcontrol *tcp;
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struct cg_proto *cg_proto;
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cg_proto = tcp_prot.proto_cgroup((struct mem_cgroup *)memcg);
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if (!cg_proto)
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return 0;
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tcp = tcp_from_cgproto(cg_proto);
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return res_counter_read_u64(&tcp->tcp_memory_allocated, RES_LIMIT);
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}
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void tcp_prot_mem(struct mem_cgroup *memcg, long val, int idx)
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{
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struct tcp_memcontrol *tcp;
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struct cg_proto *cg_proto;
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cg_proto = tcp_prot.proto_cgroup(memcg);
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if (!cg_proto)
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return;
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tcp = tcp_from_cgproto(cg_proto);
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tcp->tcp_prot_mem[idx] = val;
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}
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static struct cftype tcp_files[] = {
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{
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.name = "kmem.tcp.limit_in_bytes",
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.write_string = tcp_cgroup_write,
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.read_u64 = tcp_cgroup_read,
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.private = RES_LIMIT,
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},
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{
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.name = "kmem.tcp.usage_in_bytes",
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.read_u64 = tcp_cgroup_read,
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.private = RES_USAGE,
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},
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{
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.name = "kmem.tcp.failcnt",
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.private = RES_FAILCNT,
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.trigger = tcp_cgroup_reset,
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.read_u64 = tcp_cgroup_read,
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},
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{
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.name = "kmem.tcp.max_usage_in_bytes",
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.private = RES_MAX_USAGE,
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.trigger = tcp_cgroup_reset,
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.read_u64 = tcp_cgroup_read,
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},
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{ } /* terminate */
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};
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static int __init tcp_memcontrol_init(void)
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{
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WARN_ON(cgroup_add_cftypes(&mem_cgroup_subsys, tcp_files));
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return 0;
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}
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__initcall(tcp_memcontrol_init);
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