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