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