net/ipv4/tcp_memcontrol.c

   1 #include <net/tcp.h>
   2 #include <net/tcp_memcontrol.h>
   3 #include <net/sock.h>
   4 #include <net/ip.h>
   5 #include <linux/nsproxy.h>
   6 #include <linux/memcontrol.h>
   7 #include <linux/module.h>
   8
   9 static inline struct tcp_memcontrol *tcp_from_cgproto(struct cg_proto *cg_proto)
  10 {
  11         return container_of(cg_proto, struct tcp_memcontrol, cg_proto);
  12 }
  13
  14 static void memcg_tcp_enter_memory_pressure(struct sock *sk)
  15 {
  16         if (sk->sk_cgrp->memory_pressure)
  17                 *sk->sk_cgrp->memory_pressure = 1;
  18 }
  19 EXPORT_SYMBOL(memcg_tcp_enter_memory_pressure);
  20
  21 int tcp_init_cgroup(struct mem_cgroup *memcg, struct cgroup_subsys *ss)
  22 {
  23         /*
  24          * The root cgroup does not use res_counters, but rather,
  25          * rely on the data already collected by the network
  26          * subsystem
  27          */
  28         struct res_counter *res_parent = NULL;
  29         struct cg_proto *cg_proto, *parent_cg;
  30         struct tcp_memcontrol *tcp;
  31         struct mem_cgroup *parent = parent_mem_cgroup(memcg);
  32         struct net *net = current->nsproxy->net_ns;
  33
  34         cg_proto = tcp_prot.proto_cgroup(memcg);
  35         if (!cg_proto)
  36                 return 0;
  37
  38         tcp = tcp_from_cgproto(cg_proto);
  39
  40         tcp->tcp_prot_mem[0] = net->ipv4.sysctl_tcp_mem[0];
  41         tcp->tcp_prot_mem[1] = net->ipv4.sysctl_tcp_mem[1];
  42         tcp->tcp_prot_mem[2] = net->ipv4.sysctl_tcp_mem[2];
  43         tcp->tcp_memory_pressure = 0;
  44
  45         parent_cg = tcp_prot.proto_cgroup(parent);
  46         if (parent_cg)
  47                 res_parent = parent_cg->memory_allocated;
  48
  49         res_counter_init(&tcp->tcp_memory_allocated, res_parent);
  50         percpu_counter_init(&tcp->tcp_sockets_allocated, 0);
  51
  52         cg_proto->enter_memory_pressure = memcg_tcp_enter_memory_pressure;
  53         cg_proto->memory_pressure = &tcp->tcp_memory_pressure;
  54         cg_proto->sysctl_mem = tcp->tcp_prot_mem;
  55         cg_proto->memory_allocated = &tcp->tcp_memory_allocated;
  56         cg_proto->sockets_allocated = &tcp->tcp_sockets_allocated;
  57         cg_proto->memcg = memcg;
  58
  59         return 0;
  60 }
  61 EXPORT_SYMBOL(tcp_init_cgroup);
  62
  63 void tcp_destroy_cgroup(struct mem_cgroup *memcg)
  64 {
  65         struct cg_proto *cg_proto;
  66         struct tcp_memcontrol *tcp;
  67
  68         cg_proto = tcp_prot.proto_cgroup(memcg);
  69         if (!cg_proto)
  70                 return;
  71
  72         tcp = tcp_from_cgproto(cg_proto);
  73         percpu_counter_destroy(&tcp->tcp_sockets_allocated);
  74 }
  75 EXPORT_SYMBOL(tcp_destroy_cgroup);
  76
  77 static int tcp_update_limit(struct mem_cgroup *memcg, u64 val)
  78 {
  79         struct net *net = current->nsproxy->net_ns;
  80         struct tcp_memcontrol *tcp;
  81         struct cg_proto *cg_proto;
  82         u64 old_lim;
  83         int i;
  84         int ret;
  85
  86         cg_proto = tcp_prot.proto_cgroup(memcg);
  87         if (!cg_proto)
  88                 return -EINVAL;
  89
  90         if (val > RES_COUNTER_MAX)
  91                 val = RES_COUNTER_MAX;
  92
  93         tcp = tcp_from_cgproto(cg_proto);
  94
  95         old_lim = res_counter_read_u64(&tcp->tcp_memory_allocated, RES_LIMIT);
  96         ret = res_counter_set_limit(&tcp->tcp_memory_allocated, val);
  97         if (ret)
  98                 return ret;
  99
 100         for (i = 0; i < 3; i++)
 101                 tcp->tcp_prot_mem[i] = min_t(long, val >> PAGE_SHIFT,
 102                                              net->ipv4.sysctl_tcp_mem[i]);
 103
 104         if (val == RES_COUNTER_MAX)
 105                 clear_bit(MEMCG_SOCK_ACTIVE, &cg_proto->flags);
 106         else if (val != RES_COUNTER_MAX) {
 107                 /*
 108                  * The active bit needs to be written after the static_key
 109                  * update. This is what guarantees that the socket activation
 110                  * function is the last one to run. See sock_update_memcg() for
 111                  * details, and note that we don't mark any socket as belonging
 112                  * to this memcg until that flag is up.
 113                  *
 114                  * We need to do this, because static_keys will span multiple
 115                  * sites, but we can't control their order. If we mark a socket
 116                  * as accounted, but the accounting functions are not patched in
 117                  * yet, we'll lose accounting.
 118                  *
 119                  * We never race with the readers in sock_update_memcg(),
 120                  * because when this value change, the code to process it is not
 121                  * patched in yet.
 122                  *
 123                  * The activated bit is used to guarantee that no two writers
 124                  * will do the update in the same memcg. Without that, we can't
 125                  * properly shutdown the static key.
 126                  */
 127                 if (!test_and_set_bit(MEMCG_SOCK_ACTIVATED, &cg_proto->flags))
 128                         static_key_slow_inc(&memcg_socket_limit_enabled);
 129                 set_bit(MEMCG_SOCK_ACTIVE, &cg_proto->flags);
 130         }
 131
 132         return 0;
 133 }
 134
 135 static int tcp_cgroup_write(struct cgroup_subsys_state *css, struct cftype *cft,
 136                             const char *buffer)
 137 {
 138         struct mem_cgroup *memcg = mem_cgroup_from_css(css);
 139         unsigned long long val;
 140         int ret = 0;
 141
 142         switch (cft->private) {
 143         case RES_LIMIT:
 144                 /* see memcontrol.c */
 145                 ret = res_counter_memparse_write_strategy(buffer, &val);
 146                 if (ret)
 147                         break;
 148                 ret = tcp_update_limit(memcg, val);
 149                 break;
 150         default:
 151                 ret = -EINVAL;
 152                 break;
 153         }
 154         return ret;
 155 }
 156
 157 static u64 tcp_read_stat(struct mem_cgroup *memcg, int type, u64 default_val)
 158 {
 159         struct tcp_memcontrol *tcp;
 160         struct cg_proto *cg_proto;
 161
 162         cg_proto = tcp_prot.proto_cgroup(memcg);
 163         if (!cg_proto)
 164                 return default_val;
 165
 166         tcp = tcp_from_cgproto(cg_proto);
 167         return res_counter_read_u64(&tcp->tcp_memory_allocated, type);
 168 }
 169
 170 static u64 tcp_read_usage(struct mem_cgroup *memcg)
 171 {
 172         struct tcp_memcontrol *tcp;
 173         struct cg_proto *cg_proto;
 174
 175         cg_proto = tcp_prot.proto_cgroup(memcg);
 176         if (!cg_proto)
 177                 return atomic_long_read(&tcp_memory_allocated) << PAGE_SHIFT;
 178
 179         tcp = tcp_from_cgproto(cg_proto);
 180         return res_counter_read_u64(&tcp->tcp_memory_allocated, RES_USAGE);
 181 }
 182
 183 static u64 tcp_cgroup_read(struct cgroup_subsys_state *css, struct cftype *cft)
 184 {
 185         struct mem_cgroup *memcg = mem_cgroup_from_css(css);
 186         u64 val;
 187
 188         switch (cft->private) {
 189         case RES_LIMIT:
 190                 val = tcp_read_stat(memcg, RES_LIMIT, RES_COUNTER_MAX);
 191                 break;
 192         case RES_USAGE:
 193                 val = tcp_read_usage(memcg);
 194                 break;
 195         case RES_FAILCNT:
 196         case RES_MAX_USAGE:
 197                 val = tcp_read_stat(memcg, cft->private, 0);
 198                 break;
 199         default:
 200                 BUG();
 201         }
 202         return val;
 203 }
 204
 205 static int tcp_cgroup_reset(struct cgroup_subsys_state *css, unsigned int event)
 206 {
 207         struct mem_cgroup *memcg;
 208         struct tcp_memcontrol *tcp;
 209         struct cg_proto *cg_proto;
 210
 211         memcg = mem_cgroup_from_css(css);
 212         cg_proto = tcp_prot.proto_cgroup(memcg);
 213         if (!cg_proto)
 214                 return 0;
 215         tcp = tcp_from_cgproto(cg_proto);
 216
 217         switch (event) {
 218         case RES_MAX_USAGE:
 219                 res_counter_reset_max(&tcp->tcp_memory_allocated);
 220                 break;
 221         case RES_FAILCNT:
 222                 res_counter_reset_failcnt(&tcp->tcp_memory_allocated);
 223                 break;
 224         }
 225
 226         return 0;
 227 }
 228
 229 unsigned long long tcp_max_memory(const struct mem_cgroup *memcg)
 230 {
 231         struct tcp_memcontrol *tcp;
 232         struct cg_proto *cg_proto;
 233
 234         cg_proto = tcp_prot.proto_cgroup((struct mem_cgroup *)memcg);
 235         if (!cg_proto)
 236                 return 0;
 237
 238         tcp = tcp_from_cgproto(cg_proto);
 239         return res_counter_read_u64(&tcp->tcp_memory_allocated, RES_LIMIT);
 240 }
 241
 242 void tcp_prot_mem(struct mem_cgroup *memcg, long val, int idx)
 243 {
 244         struct tcp_memcontrol *tcp;
 245         struct cg_proto *cg_proto;
 246
 247         cg_proto = tcp_prot.proto_cgroup(memcg);
 248         if (!cg_proto)
 249                 return;
 250
 251         tcp = tcp_from_cgproto(cg_proto);
 252
 253         tcp->tcp_prot_mem[idx] = val;
 254 }
 255
 256 static struct cftype tcp_files[] = {
 257         {
 258                 .name = "kmem.tcp.limit_in_bytes",
 259                 .write_string = tcp_cgroup_write,
 260                 .read_u64 = tcp_cgroup_read,
 261                 .private = RES_LIMIT,
 262         },
 263         {
 264                 .name = "kmem.tcp.usage_in_bytes",
 265                 .read_u64 = tcp_cgroup_read,
 266                 .private = RES_USAGE,
 267         },
 268         {
 269                 .name = "kmem.tcp.failcnt",
 270                 .private = RES_FAILCNT,
 271                 .trigger = tcp_cgroup_reset,
 272                 .read_u64 = tcp_cgroup_read,
 273         },
 274         {
 275                 .name = "kmem.tcp.max_usage_in_bytes",
 276                 .private = RES_MAX_USAGE,
 277                 .trigger = tcp_cgroup_reset,
 278                 .read_u64 = tcp_cgroup_read,
 279         },
 280         { }     /* terminate */
 281 };
 282
 283 static int __init tcp_memcontrol_init(void)
 284 {
 285         WARN_ON(cgroup_add_cftypes(&mem_cgroup_subsys, tcp_files));
 286         return 0;
 287 }
 288 __initcall(tcp_memcontrol_init);