Made NIO constraint detector much more robust against indefinite blocking by enabling timeout (7 secs)
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Trustin Lee
parent
288c693f62
commit
14a49ed042
@ -30,13 +30,16 @@ import java.nio.channels.Selector;
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import java.nio.channels.ServerSocketChannel;
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import java.nio.channels.spi.SelectorProvider;
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import java.util.Set;
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import java.util.concurrent.BlockingQueue;
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import java.util.concurrent.ExecutorService;
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import java.util.concurrent.Executors;
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import java.util.concurrent.LinkedBlockingQueue;
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import java.util.concurrent.TimeUnit;
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import org.jboss.netty.logging.InternalLogger;
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import org.jboss.netty.logging.InternalLoggerFactory;
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import org.jboss.netty.util.SystemPropertyUtil;
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import org.jboss.netty.util.ThreadRenamingRunnable;
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/**
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* Provides information which is specific to a NIO service provider
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@ -55,6 +58,8 @@ class NioProviderMetadata {
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private static final String CONSTRAINT_LEVEL_PROPERTY =
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"java.nio.channels.spi.constraintLevel";
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private static final long AUTODETECTION_TIMEOUT = 7000L;
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/**
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* 0 - no need to wake up to get / set interestOps (most cases)
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* 1 - no need to wake up to get interestOps, but need to wake up to set.
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@ -86,7 +91,16 @@ class NioProviderMetadata {
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if (constraintLevel < 0) {
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logger.debug(
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"Couldn't get the NIO constraint level from the system properties.");
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constraintLevel = detectConstraintLevel();
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ConstraintLevelAutodetector autodetector =
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new ConstraintLevelAutodetector();
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try {
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constraintLevel = autodetector.autodetectWithTimeout();
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} catch (Exception e) {
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// Probably because of security manager - try again without
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// creating a new thread directly.
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constraintLevel = autodetector.autodetectWithoutTimeout();
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}
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}
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if (constraintLevel < 0) {
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@ -212,84 +226,90 @@ class NioProviderMetadata {
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return -1;
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}
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private static int detectConstraintLevel() {
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// TODO Code cleanup - what a mess.
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final int constraintLevel;
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ExecutorService executor = Executors.newCachedThreadPool();
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boolean success;
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long startTime;
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int interestOps;
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ServerSocketChannel ch = null;
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SelectorLoop loop = null;
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private static class ConstraintLevelAutodetector {
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try {
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// Open a channel.
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ch = ServerSocketChannel.open();
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ConstraintLevelAutodetector() {
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super();
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}
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// Configure the channel
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try {
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ch.socket().bind(new InetSocketAddress(0));
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ch.configureBlocking(false);
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} catch (IOException e) {
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logger.warn("Failed to configure a temporary socket.", e);
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return -1;
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}
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// Prepare the selector loop.
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try {
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loop = new SelectorLoop();
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} catch (IOException e) {
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logger.warn("Failed to open a temporary selector.", e);
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return -1;
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}
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// Register the channel
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try {
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ch.register(loop.selector, 0);
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} catch (ClosedChannelException e) {
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logger.warn("Failed to register a temporary selector.", e);
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return -1;
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}
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SelectionKey key = ch.keyFor(loop.selector);
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// Start the selector loop.
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executor.execute(loop);
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// Level 0
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success = true;
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for (int i = 0; i < 10; i ++) {
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// Increase the probability of calling interestOps
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// while select() is running.
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do {
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while (!loop.selecting) {
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Thread.yield();
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}
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// Wait a little bit more.
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int autodetectWithTimeout() {
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final BlockingQueue<Integer> resultQueue = new LinkedBlockingQueue<Integer>();
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Runnable detector = new ThreadRenamingRunnable(new Runnable() {
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public void run() {
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int level = -1;
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try {
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Thread.sleep(50);
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} catch (InterruptedException e) {
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// Ignore
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level = autodetectWithoutTimeout();
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} finally {
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resultQueue.offer(Integer.valueOf(level));
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}
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} while (!loop.selecting);
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}
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}, "NIO constraint level detector");
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startTime = System.nanoTime();
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key.interestOps(key.interestOps() | SelectionKey.OP_ACCEPT);
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key.interestOps(key.interestOps() & ~SelectionKey.OP_ACCEPT);
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Thread detectorThread = new Thread(detector);
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detectorThread.start();
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if (System.nanoTime() - startTime >= 500000000L) {
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success = false;
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break;
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for (;;) {
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try {
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Integer result = resultQueue.poll(AUTODETECTION_TIMEOUT, TimeUnit.MILLISECONDS);
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if (result == null) {
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logger.warn("NIO constraint level autodetection timed out.");
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return -1;
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} else {
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return result.intValue();
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}
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} catch (InterruptedException e) {
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// Ignored
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}
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}
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}
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if (success) {
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constraintLevel = 0;
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} else {
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// Level 1
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int autodetectWithoutTimeout() {
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// TODO Code cleanup - what a mess.
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final int constraintLevel;
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ExecutorService executor = Executors.newCachedThreadPool();
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boolean success;
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long startTime;
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int interestOps;
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ServerSocketChannel ch = null;
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SelectorLoop loop = null;
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try {
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// Open a channel.
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ch = ServerSocketChannel.open();
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// Configure the channel
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try {
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ch.socket().bind(new InetSocketAddress(0));
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ch.configureBlocking(false);
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} catch (IOException e) {
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logger.warn("Failed to configure a temporary socket.", e);
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return -1;
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}
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// Prepare the selector loop.
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try {
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loop = new SelectorLoop();
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} catch (IOException e) {
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logger.warn("Failed to open a temporary selector.", e);
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return -1;
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}
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// Register the channel
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try {
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ch.register(loop.selector, 0);
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} catch (ClosedChannelException e) {
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logger.warn("Failed to register a temporary selector.", e);
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return -1;
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}
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SelectionKey key = ch.keyFor(loop.selector);
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// Start the selector loop.
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executor.execute(loop);
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// Level 0
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success = true;
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for (int i = 0; i < 10; i ++) {
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@ -309,62 +329,95 @@ class NioProviderMetadata {
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} while (!loop.selecting);
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startTime = System.nanoTime();
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interestOps = key.interestOps();
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synchronized (loop) {
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loop.selector.wakeup();
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key.interestOps(interestOps | SelectionKey.OP_ACCEPT);
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key.interestOps(interestOps & ~SelectionKey.OP_ACCEPT);
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}
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key.interestOps(key.interestOps() | SelectionKey.OP_ACCEPT);
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key.interestOps(key.interestOps() & ~SelectionKey.OP_ACCEPT);
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if (System.nanoTime() - startTime >= 500000000L) {
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success = false;
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break;
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}
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}
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if (success) {
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constraintLevel = 1;
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} else {
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constraintLevel = 2;
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}
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}
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} catch (IOException e) {
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return -1;
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} finally {
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if (ch != null) {
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try {
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ch.close();
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} catch (IOException e) {
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logger.warn("Failed to close a temporary socket.", e);
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}
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}
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if (loop != null) {
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loop.done = true;
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loop.selector.wakeup();
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try {
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executor.shutdownNow();
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for (;;) {
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try {
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if (executor.awaitTermination(1, TimeUnit.SECONDS)) {
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break;
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if (success) {
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constraintLevel = 0;
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} else {
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// Level 1
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success = true;
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for (int i = 0; i < 10; i ++) {
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// Increase the probability of calling interestOps
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// while select() is running.
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do {
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while (!loop.selecting) {
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Thread.yield();
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}
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} catch (InterruptedException e) {
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// Ignore
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// Wait a little bit more.
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try {
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Thread.sleep(50);
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} catch (InterruptedException e) {
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// Ignore
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}
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} while (!loop.selecting);
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startTime = System.nanoTime();
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interestOps = key.interestOps();
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synchronized (loop) {
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loop.selector.wakeup();
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key.interestOps(interestOps | SelectionKey.OP_ACCEPT);
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key.interestOps(interestOps & ~SelectionKey.OP_ACCEPT);
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}
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if (System.nanoTime() - startTime >= 500000000L) {
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success = false;
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break;
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}
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}
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} catch (Exception e) {
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// Perhaps security exception.
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if (success) {
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constraintLevel = 1;
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} else {
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constraintLevel = 2;
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}
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}
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} catch (IOException e) {
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return -1;
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} finally {
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if (ch != null) {
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try {
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ch.close();
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} catch (IOException e) {
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logger.warn("Failed to close a temporary socket.", e);
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}
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}
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try {
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loop.selector.close();
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} catch (IOException e) {
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logger.warn("Failed to close a temporary selector.", e);
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if (loop != null) {
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loop.done = true;
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executor.shutdownNow();
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try {
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for (;;) {
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loop.selector.wakeup();
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try {
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if (executor.awaitTermination(1, TimeUnit.SECONDS)) {
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break;
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}
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} catch (InterruptedException e) {
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// Ignore
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}
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}
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} catch (Exception e) {
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// Perhaps security exception.
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}
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try {
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loop.selector.close();
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} catch (IOException e) {
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logger.warn("Failed to close a temporary selector.", e);
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}
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}
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}
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}
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return constraintLevel;
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return constraintLevel;
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}
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}
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private static class SelectorLoop implements Runnable {
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