7200742: (se) Selector.select does not block when starting Coherence (sol)

Reviewed-by: chegar

src/solaris/classes/sun/nio/ch/DevPollArrayWrapper.java

@@ -68,7 +68,7 @@ class DevPollArrayWrapper {
     static final short REVENT_OFFSET = 6;
 
     // Special value to indicate that an update should be ignored
-    static final byte  CANCELLED     = (byte)-1;
+    static final byte  IGNORE        = (byte)-1;
 
     // Maximum number of open file descriptors
     static final int   OPEN_MAX      = IOUtil.fdLimit();
@@ -192,15 +192,15 @@ class DevPollArrayWrapper {
 
             // events are stored as bytes for efficiency reasons
             byte b = (byte)mask;
-            assert (b == mask) && (b != CANCELLED);
+            assert (b == mask) && (b != IGNORE);
             setUpdateEvents(fd, b);
         }
     }
 
     void release(int fd) {
         synchronized (updateLock) {
-            // cancel any pending update for this file descriptor
-            setUpdateEvents(fd, CANCELLED);
+            // ignore any pending update for this file descriptor
+            setUpdateEvents(fd, IGNORE);
 
             // remove from /dev/poll
             if (registered.get(fd)) {
@@ -236,32 +236,40 @@ class DevPollArrayWrapper {
             while (j < updateCount) {
                 int fd = updateDescriptors[j];
                 short events = getUpdateEvents(fd);
-                boolean isRegistered = registered.get(fd);
+                boolean wasRegistered = registered.get(fd);
 
                 // events = 0 => POLLREMOVE or do-nothing
-                if (events != CANCELLED) {
+                if (events != IGNORE) {
                     if (events == 0) {
-                        if (isRegistered) {
+                        if (wasRegistered) {
                             events = POLLREMOVE;
                             registered.clear(fd);
                         } else {
-                            events = CANCELLED;
+                            events = IGNORE;
                         }
                     } else {
-                        if (!isRegistered) {
+                        if (!wasRegistered) {
                             registered.set(fd);
                         }
                     }
                 }
 
                 // populate pollfd array with updated event
-                if (events != CANCELLED) {
+                if (events != IGNORE) {
+                    // insert POLLREMOVE if changing events
+                    if (wasRegistered && events != POLLREMOVE) {
+                        putPollFD(pollArray, index, fd, POLLREMOVE);
+                        index++;
+                    }
                     putPollFD(pollArray, index, fd, events);
                     index++;
-                    if (index >= NUM_POLLFDS) {
+                    if (index >= (NUM_POLLFDS-1)) {
                         registerMultiple(wfd, pollArray.address(), index);
                         index = 0;
                     }
+
+                    // events for this fd now up to date
+                    setUpdateEvents(fd, IGNORE);
                 }
                 j++;
             }

test/java/nio/channels/Selector/ChangingInterests.java

+/*
+ * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/* @test
+ * @bug 7200742
+ * @summary Test that Selector doesn't spin when changing interest ops
+ */
+
+import java.net.*;
+import java.nio.ByteBuffer;
+import java.nio.channels.*;
+import static java.nio.channels.SelectionKey.*;
+import java.io.IOException;
+
+public class ChangingInterests {
+
+    static int OPS[] = { 0, OP_WRITE, OP_READ, (OP_WRITE|OP_READ) };
+
+    static String toOpsString(int ops) {
+        String s = "";
+        if ((ops & OP_READ) > 0)
+            s += "POLLIN";
+        if ((ops & OP_WRITE) > 0) {
+            if (s.length() > 0)
+                s += "|";
+            s += "POLLOUT";
+        }
+        if (s.length() == 0)
+            s = "0";
+        return "(" + s + ")";
+    }
+
+    static void write1(SocketChannel peer) throws IOException {
+        peer.write(ByteBuffer.wrap(new byte[1]));
+        // give time for other end to be readable
+        try {
+            Thread.sleep(50);
+        } catch (InterruptedException ignore) { }
+    }
+
+    static void drain(SocketChannel sc) throws IOException {
+        ByteBuffer buf = ByteBuffer.allocate(100);
+        int n;
+        while ((n = sc.read(buf)) > 0) {
+            buf.rewind();
+        }
+    }
+
+    /**
+     * Changes the given key's interest set from one set to another and then
+     * checks the selected key set and the key's channel.
+     */
+    static void testChange(SelectionKey key, int from, int to) throws IOException {
+        Selector sel = key.selector();
+        assertTrue(sel.keys().size() == 1, "Only one channel should be registered");
+
+        // ensure that channel is registered with the "from" interest set
+        key.interestOps(from);
+        sel.selectNow();
+        sel.selectedKeys().clear();
+
+        // change to the "to" interest set
+        key.interestOps(to);
+        System.out.println("select...");
+        int selected = sel.selectNow();
+        System.out.println("" + selected + " channel(s) selected");
+
+        int expected = (to == 0) ? 0 : 1;
+        assertTrue(selected == expected, "Expected " + expected);
+
+        // check selected keys
+        for (SelectionKey k: sel.selectedKeys()) {
+            assertTrue(k == key, "Unexpected key selected");
+
+            boolean readable = k.isReadable();
+            boolean writable = k.isWritable();
+
+            System.out.println("key readable: " + readable);
+            System.out.println("key writable: " + writable);
+
+            if ((to & OP_READ) == 0) {
+                assertTrue(!readable, "Not expected to be readable");
+            } else {
+                assertTrue(readable, "Expected to be readable");
+            }
+
+            if ((to & OP_WRITE) == 0) {
+                assertTrue(!writable, "Not expected to be writable");
+            } else {
+                assertTrue(writable, "Expected to be writable");
+            }
+
+            sel.selectedKeys().clear();
+        }
+    }
+
+    /**
+     * Tests that given Selector's select method blocks.
+     */
+    static void testForSpin(Selector sel) throws IOException {
+        System.out.println("Test for spin...");
+        long start = System.currentTimeMillis();
+        int count = 3;
+        while (count-- > 0) {
+            int selected = sel.select(1000);
+            System.out.println("" + selected + " channel(s) selected");
+            assertTrue(selected == 0, "Channel should not be selected");
+        }
+        long dur = System.currentTimeMillis() - start;
+        assertTrue(dur > 1000, "select was too short");
+    }
+
+    public static void main(String[] args) throws IOException {
+        InetAddress lh = InetAddress.getLocalHost();
+
+        // create loopback connection
+        ServerSocketChannel ssc =
+            ServerSocketChannel.open().bind(new InetSocketAddress(0));
+
+        final SocketChannel sc = SocketChannel.open();
+        sc.connect(new InetSocketAddress(lh, ssc.socket().getLocalPort()));
+        SocketChannel peer = ssc.accept();
+
+        sc.configureBlocking(false);
+
+        // ensure that channel "sc" is readable
+        write1(peer);
+
+        try (Selector sel = Selector.open()) {
+            SelectionKey key = sc.register(sel, 0);
+            sel.selectNow();
+
+            // test all transitions
+            for (int from: OPS) {
+                for (int to: OPS) {
+
+                    System.out.println(toOpsString(from) + " -> " + toOpsString(to));
+
+                    testChange(key, from, to);
+
+                    // if the interst ops is now 0 then Selector should not spin
+                    if (to == 0)
+                        testForSpin(sel);
+
+                    // if interest ops is now OP_READ then make non-readable
+                    // and test that Selector does not spin.
+                    if (to == OP_READ) {
+                        System.out.println("Drain channel...");
+                        drain(sc);
+                        testForSpin(sel);
+                        System.out.println("Make channel readable again");
+                        write1(peer);
+                    }
+
+                    System.out.println();
+                }
+            }
+
+        } finally {
+            sc.close();
+            peer.close();
+            ssc.close();
+        }
+    }
+
+    static void assertTrue(boolean v, String msg) {
+        if (!v) throw new RuntimeException(msg);
+    }
+
+}