socket内存占用疑问？

web@haha ~> cat /proc/sys/net/ipv4/tcp_rmem
4096	87380	4161536
web@haha ~> cat /proc/sys/net/ipv4/tcp_wmem
4096	16384	4161536
web@haha ~> cat /proc/sys/net/ipv4/tcp_mem
24180	32241	48360

2.测试环境
简单的阿里云服务器，1核1G。。
3.测试代码，java狗o(╯□╰)o，10000个链接去连本地的9090端口

final Selector selector = Selector.open();
        InetSocketAddress addr = new InetSocketAddress("127.0.0.1", 9090);
        long start = System.currentTimeMillis();
        int connected = 0;
        int currentConnectionPerIP = 0;
        System.out.println("begin");
        while (true) {
            if (System.currentTimeMillis() - start > 1000 * 60 * 10) {
                break;
            }
            for (; currentConnectionPerIP < 10000; currentConnectionPerIP++) {
                    SocketChannel ch = SocketChannel.open();
                    ch.configureBlocking(false);
                    Socket s = ch.socket();
                    s.setReuseAddress(true);
                    ch.register(selector, SelectionKey.OP_CONNECT);
                    ch.connect(addr);
            }

            int select = selector.select(1000 * 10); // 10s
            if (select > 0) {
                Set<SelectionKey> selectedKeys = selector.selectedKeys();
                Iterator<SelectionKey> it = selectedKeys.iterator();

                while (it.hasNext()) {
                    SelectionKey key = it.next();
                    if (key.isConnectable()) {
                        SocketChannel ch = (SocketChannel) key.channel();
                        if (ch.finishConnect()) {
                            ++connected;
                            if (connected % (connectionPerIP / 10) == 0) {
                                System.out.println("connected: " + connected);
                            }
                            key.interestOps(SelectionKey.OP_READ);
                        }
                    }
                }
                selectedKeys.clear();
            }
        }

4.测试结果

web@haha ~> cat /proc/net/sockstat
sockets: used 20251
TCP: inuse 20053 orphan 0 tw 10 alloc 20054 mem 3
UDP: inuse 7 mem 2
UDPLITE: inuse 0
RAW: inuse 0
FRAG: inuse 0 memory 0

代码运行前内存

web@haha ~> free -m
             total       used       free     shared    buffers     cached
Mem:           994        825        168          0          9         86
-/+ buffers/cache:        728        265
Swap:            0          0          0

代码运行时内存

web@haha ~> free -m
             total       used       free     shared    buffers     cached
Mem:           994        908         85          0          9         86
-/+ buffers/cache:        812        181
Swap:            0          0          0

5.疑问
为什么内存才变化了80多M啊？这里tcp socket内存大小我没改啊，那就读+写=86+16，按100k来算的话，1w个链接不应该才消耗这么少内存啊？修改