Add polling POLLOUT

Motivation:

no checks for non writeable sockets

Modifications:

-Added a linked write poll to make sure that the socket does not write if it is not writeable
-Added a new boolean to avoid to submit a second write operation

Result:

writeable socket check

transport-native-io_uring/src/main/java/io/netty/channel/uring/AbstractIOUringChannel.java

@@ -40,6 +40,7 @@ import java.nio.channels.UnresolvedAddressException;
 import static io.netty.util.internal.ObjectUtil.*;
 
 abstract class AbstractIOUringChannel extends AbstractChannel implements UnixChannel {
+    private static final InternalLogger logger = InternalLoggerFactory.getInstance(AbstractIOUringChannel.class);
     private static final ChannelMetadata METADATA = new ChannelMetadata(false);
     final LinuxSocket socket;
     protected volatile boolean active;
@@ -233,7 +234,8 @@ abstract class AbstractIOUringChannel extends AbstractChannel implements UnixCha
 
     @Override
     protected void doWrite(ChannelOutboundBuffer in) throws Exception {
-        if (in.size() >= 1) {
+        logger.info("IOUring doWrite message size: {}", in.size());
+        if (writeable && in.size() >= 1) {
             Object msg = in.current();
             if (msg instanceof ByteBuf) {
                 doWriteBytes((ByteBuf) msg);
@@ -243,6 +245,9 @@ abstract class AbstractIOUringChannel extends AbstractChannel implements UnixCha
 
     protected final void doWriteBytes(ByteBuf buf) {
         if (buf.hasMemoryAddress()) {
+            //link poll<link>write operation
+            addPollOut();
+
             IOUringEventLoop ioUringEventLoop = (IOUringEventLoop) eventLoop();
             IOUringSubmissionQueue submissionQueue = ioUringEventLoop.getRingBuffer().getIoUringSubmissionQueue();
             final Event event = new Event();
@@ -254,9 +259,24 @@ abstract class AbstractIOUringChannel extends AbstractChannel implements UnixCha
                                 buf.writerIndex());
             ioUringEventLoop.addNewEvent(event);
             submissionQueue.submit();
+            writeable = false;
         }
     }
 
+    //POLLOUT
+    private void addPollOut() {
+        IOUringEventLoop ioUringEventLoop = (IOUringEventLoop) eventLoop();
+        IOUringSubmissionQueue submissionQueue = ioUringEventLoop.getRingBuffer().getIoUringSubmissionQueue();
+        final Event event = new Event();
+        long eventId = ioUringEventLoop.incrementEventIdCounter();
+        event.setId(eventId);
+        event.setOp(EventType.POLL_OUT);
+        event.setAbstractIOUringChannel(this);
+        submissionQueue.addPoll(eventId, socket.intValue(), EventType.POLL_OUT);
+        ioUringEventLoop.addNewEvent(event);
+        submissionQueue.submit();
+    }
+
     abstract class AbstractUringUnsafe extends AbstractUnsafe {
         private IOUringRecvByteAllocatorHandle allocHandle;
         private final Runnable readRunnable = new Runnable() {

transport-native-io_uring/src/main/java/io/netty/channel/uring/AbstractIOUringStreamChannel.java

@@ -1,3 +1,18 @@
+/*
+ * Copyright 2020 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
 package io.netty.channel.uring;
 
 import io.netty.buffer.ByteBuf;

transport-native-io_uring/src/main/java/io/netty/channel/uring/IOUringEventLoop.java

@@ -16,6 +16,7 @@
 package io.netty.channel.uring;
 
 import io.netty.buffer.ByteBuf;
+import io.netty.channel.Channel;
 import io.netty.channel.ChannelOutboundBuffer;
 import io.netty.channel.ChannelPipeline;
 import io.netty.channel.EventLoopGroup;
@@ -24,7 +25,10 @@ import io.netty.channel.unix.FileDescriptor;
 import io.netty.util.collection.IntObjectHashMap;
 import io.netty.util.collection.IntObjectMap;
 import io.netty.util.collection.LongObjectHashMap;
+import io.netty.util.internal.logging.InternalLogger;
+import io.netty.util.internal.logging.InternalLoggerFactory;
 
+import java.io.IOException;
 import java.util.concurrent.Executor;
 import java.util.concurrent.atomic.AtomicLong;
 
@@ -63,7 +67,8 @@ final class IOUringEventLoop extends SingleThreadEventLoop {
 
     IOUringEventLoop(final EventLoopGroup parent, final Executor executor, final boolean addTaskWakesUp) {
         super(parent, executor, addTaskWakesUp);
-        ringBuffer = Native.createRingBuffer(32);
+
+        ringBuffer = Native.createRingBuffer(ringSize);
         eventfd = Native.newEventFd();
         long eventId = incrementEventIdCounter();
         Event event = new Event();
@@ -241,22 +246,27 @@ final class IOUringEventLoop extends SingleThreadEventLoop {
             event.getAbstractIOUringChannel().executeReadEvent();
         break;
         case WRITE:
-            System.out.println("EventLoop Write Res: " + res);
+            //localFlushAmount -> res
-            System.out.println("EventLoop Fd: " + event.getAbstractIOUringChannel().getSocket().intValue());
+            logger.info("EventLoop Write Res: {}", res);
-            System.out.println("EventLoop Pipeline: " + event.getAbstractIOUringChannel().eventLoop());
+            logger.info("EventLoop Fd: {}", event.getAbstractIOUringChannel().getSocket().intValue());
             ChannelOutboundBuffer channelOutboundBuffer = event
                     .getAbstractIOUringChannel().unsafe().outboundBuffer();
-            //remove bytes
+            AbstractIOUringChannel channel = event.getAbstractIOUringChannel();
-            int localFlushAmount = res;
+
-            if (localFlushAmount > 0) {
+            if (res == SOCKET_ERROR_EPIPE) {
-                channelOutboundBuffer.removeBytes(localFlushAmount);
+                event.getAbstractIOUringChannel().shutdownInput(false);
+                break;
             }
 
+            if (res > 0) {
+                channelOutboundBuffer.removeBytes(res);
+                channel.setWriteable(true);
                 try {
                     event.getAbstractIOUringChannel().doWrite(channelOutboundBuffer);
                 } catch (Exception e) {
                     e.printStackTrace();
                 }
+            }
             break;
         case TIMEOUT:
             if (res == ETIME) {

transport-native-io_uring/src/main/java/io/netty/channel/uring/IOUringSubmissionQueue.java

@@ -21,11 +21,15 @@ import io.netty.util.internal.PlatformDependent;
 import java.nio.ByteBuffer;
 
 final class IOUringSubmissionQueue {
+    private static final InternalLogger logger = InternalLoggerFactory.getInstance(IOUringSubmissionQueue.class);
 
     private static final int SQE_SIZE = 64;
     private static final int INT_SIZE = Integer.BYTES; //no 32 Bit support?
     private static final int KERNEL_TIMESPEC_SIZE = 16; //__kernel_timespec
     private static final int POLLIN = 1;
+    private static final int POLLRDHUP = 8192;
+    private static final int POLLOUT = 4;
+
     private static final int IOSQE_IO_LINK = 4;
 
     //these offsets are used to access specific properties
@@ -97,6 +101,9 @@ final class IOUringSubmissionQueue {
             sqe = SQE_SIZE * index + submissionQueueArrayAddress;
             sqeTail = next;
         }
+        if (sqe == 0) {
+            logger.info("sqe is null");
+        }
         return sqe;
     }
 
@@ -112,7 +119,7 @@ final class IOUringSubmissionQueue {
         PlatformDependent.putLong(sqe + SQE_USER_DATA_FIELD, eventId);
 
         //poll<link>read or accept operation
-        if (type == EventType.POLL_LINK) {
+        if (type == EventType.POLL_LINK || type == EventType.POLL_OUT) {
             PlatformDependent.putByte(sqe + SQE_FLAGS_FIELD, (byte) IOSQE_IO_LINK);
         } else {
            PlatformDependent.putByte(sqe + SQE_FLAGS_FIELD, (byte) 0);
@@ -182,9 +189,6 @@ final class IOUringSubmissionQueue {
         if (sqe == 0) {
             return false;
         }
-        System.out.println("fd " + fd);
-        System.out.println("BufferAddress + pos: " + (bufferAddress + pos));
-        System.out.println("limit + pos " + (limit - pos));
         setData(sqe, eventId, type, fd, bufferAddress + pos, limit - pos, 0);
         return true;
     }
@@ -194,10 +198,10 @@ final class IOUringSubmissionQueue {
         long kHead = toUnsignedLong(PlatformDependent.getIntVolatile(kHeadAddress));
         long kRingMask = toUnsignedLong(PlatformDependent.getInt(kRingMaskAddress));
 
-        System.out.println("Ktail: " + kTail);
+        logger.info("Ktail: {}", kTail);
-        System.out.println("Ktail: " + kHead);
+        logger.info("Ktail: {}", kHead);
-        System.out.println("SqeHead: " + sqeHead);
+        logger.info("SqeHead: {}", sqeHead);
-        System.out.println("SqeTail: " + sqeTail);
+        logger.info("SqeTail: {}", sqeTail);
 
         if (sqeHead == sqeTail) {
             return (int) (kTail - kHead);
@@ -222,7 +226,7 @@ final class IOUringSubmissionQueue {
 
     public void submit() {
         int submitted = flushSqe();
-        System.out.println("Submitted: " + submitted);
+        logger.info("Submitted: {}", submitted);
 
         int ret = Native.ioUringEnter(ringFd, submitted, 0, 0);
         if (ret < 0) {