[ROCKETMQ-191] Fix socket options

remoting/src/main/java/org/apache/rocketmq/remoting/netty/NettyRemotingServer.java

@@ -26,7 +26,9 @@ import io.netty.channel.ChannelInitializer;
 import io.netty.channel.ChannelOption;
 import io.netty.channel.EventLoopGroup;
 import io.netty.channel.SimpleChannelInboundHandler;
+import io.netty.channel.epoll.Epoll;
 import io.netty.channel.epoll.EpollEventLoopGroup;
+import io.netty.channel.epoll.EpollServerSocketChannel;
 import io.netty.channel.nio.NioEventLoopGroup;
 import io.netty.channel.socket.SocketChannel;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
@@ -105,8 +107,7 @@ public class NettyRemotingServer extends NettyRemotingAbstract implements Remoti
             }
         });
 
-        if (RemotingUtil.isLinuxPlatform() //
-            && nettyServerConfig.isUseEpollNativeSelector()) {
+        if (useEpoll()) {
             this.eventLoopGroupSelector = new EpollEventLoopGroup(nettyServerConfig.getServerSelectorThreads(), new ThreadFactory() {
                 private AtomicInteger threadIndex = new AtomicInteger(0);
                 private int threadTotal = nettyServerConfig.getServerSelectorThreads();
@@ -129,6 +130,12 @@ public class NettyRemotingServer extends NettyRemotingAbstract implements Remoti
         }
     }
 
+    private boolean useEpoll() {
+        return RemotingUtil.isLinuxPlatform()
+            && nettyServerConfig.isUseEpollNativeSelector()
+            && Epoll.isAvailable();
+    }
+
     @Override
     public void start() {
         this.defaultEventExecutorGroup = new DefaultEventExecutorGroup(
@@ -144,13 +151,14 @@ public class NettyRemotingServer extends NettyRemotingAbstract implements Remoti
             });
 
         ServerBootstrap childHandler =
-            this.serverBootstrap.group(this.eventLoopGroupBoss, this.eventLoopGroupSelector).channel(NioServerSocketChannel.class)
+            this.serverBootstrap.group(this.eventLoopGroupBoss, this.eventLoopGroupSelector)
+                .channel(useEpoll() ? EpollServerSocketChannel.class : NioServerSocketChannel.class)
                 .option(ChannelOption.SO_BACKLOG, 1024)
                 .option(ChannelOption.SO_REUSEADDR, true)
                 .option(ChannelOption.SO_KEEPALIVE, false)
                 .childOption(ChannelOption.TCP_NODELAY, true)
-                .option(ChannelOption.SO_SNDBUF, nettyServerConfig.getServerSocketSndBufSize())
-                .option(ChannelOption.SO_RCVBUF, nettyServerConfig.getServerSocketRcvBufSize())
+                .childOption(ChannelOption.SO_SNDBUF, nettyServerConfig.getServerSocketSndBufSize())
+                .childOption(ChannelOption.SO_RCVBUF, nettyServerConfig.getServerSocketRcvBufSize())
                 .localAddress(new InetSocketAddress(this.nettyServerConfig.getListenPort()))
                 .childHandler(new ChannelInitializer<SocketChannel>() {
                     @Override