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 ssize_t tcp_cgroup_write(struct kernfs_open_file *of,
 106                                 char *buf, size_t nbytes, loff_t off)
 107 {
 108         struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
 109         unsigned long long val;
 110         int ret = 0;
 111
 112         buf = strstrip(buf);
 113
 114         switch (of_cft(of)->private) {
 115         case RES_LIMIT:
 116                 /* see memcontrol.c */
 117                 ret = res_counter_memparse_write_strategy(buf, &val);
 118                 if (ret)
 119                         break;
 120                 ret = tcp_update_limit(memcg, val);
 121                 break;
 122         default:
 123                 ret = -EINVAL;
 124                 break;
 125         }
 126         return ret ?: nbytes;
 127 }
 128
 129 static u64 tcp_read_stat(struct mem_cgroup *memcg, int type, u64 default_val)
 130 {
 131         struct cg_proto *cg_proto;
 132
 133         cg_proto = tcp_prot.proto_cgroup(memcg);
 134         if (!cg_proto)
 135                 return default_val;
 136
 137         return res_counter_read_u64(&cg_proto->memory_allocated, type);
 138 }
 139
 140 static u64 tcp_read_usage(struct mem_cgroup *memcg)
 141 {
 142         struct cg_proto *cg_proto;
 143
 144         cg_proto = tcp_prot.proto_cgroup(memcg);
 145         if (!cg_proto)
 146                 return atomic_long_read(&tcp_memory_allocated) << PAGE_SHIFT;
 147
 148         return res_counter_read_u64(&cg_proto->memory_allocated, RES_USAGE);
 149 }
 150
 151 static u64 tcp_cgroup_read(struct cgroup_subsys_state *css, struct cftype *cft)
 152 {
 153         struct mem_cgroup *memcg = mem_cgroup_from_css(css);
 154         u64 val;
 155
 156         switch (cft->private) {
 157         case RES_LIMIT:
 158                 val = tcp_read_stat(memcg, RES_LIMIT, RES_COUNTER_MAX);
 159                 break;
 160         case RES_USAGE:
 161                 val = tcp_read_usage(memcg);
 162                 break;
 163         case RES_FAILCNT:
 164         case RES_MAX_USAGE:
 165                 val = tcp_read_stat(memcg, cft->private, 0);
 166                 break;
 167         default:
 168                 BUG();
 169         }
 170         return val;
 171 }
 172
 173 static ssize_t tcp_cgroup_reset(struct kernfs_open_file *of,
 174                                 char *buf, size_t nbytes, loff_t off)
 175 {
 176         struct mem_cgroup *memcg;
 177         struct cg_proto *cg_proto;
 178
 179         memcg = mem_cgroup_from_css(of_css(of));
 180         cg_proto = tcp_prot.proto_cgroup(memcg);
 181         if (!cg_proto)
 182                 return nbytes;
 183
 184         switch (of_cft(of)->private) {
 185         case RES_MAX_USAGE:
 186                 res_counter_reset_max(&cg_proto->memory_allocated);
 187                 break;
 188         case RES_FAILCNT:
 189                 res_counter_reset_failcnt(&cg_proto->memory_allocated);
 190                 break;
 191         }
 192
 193         return nbytes;
 194 }
 195
 196 static struct cftype tcp_files[] = {
 197         {
 198                 .name = "kmem.tcp.limit_in_bytes",
 199                 .write = tcp_cgroup_write,
 200                 .read_u64 = tcp_cgroup_read,
 201                 .private = RES_LIMIT,
 202         },
 203         {
 204                 .name = "kmem.tcp.usage_in_bytes",
 205                 .read_u64 = tcp_cgroup_read,
 206                 .private = RES_USAGE,
 207         },
 208         {
 209                 .name = "kmem.tcp.failcnt",
 210                 .private = RES_FAILCNT,
 211                 .write = tcp_cgroup_reset,
 212                 .read_u64 = tcp_cgroup_read,
 213         },
 214         {
 215                 .name = "kmem.tcp.max_usage_in_bytes",
 216                 .private = RES_MAX_USAGE,
 217                 .write = tcp_cgroup_reset,
 218                 .read_u64 = tcp_cgroup_read,
 219         },
 220         { }     /* terminate */
 221 };
 222
 223 static int __init tcp_memcontrol_init(void)
 224 {
 225         WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys, tcp_files));
 226         return 0;
 227 }
 228 __initcall(tcp_memcontrol_init);