| /* |
| * Copyright (c) 2008, 2013, Oracle and/or its affiliates. All rights reserved. |
| * Copyright (c) 2012 SAP SE. 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. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * 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. |
| */ |
| |
| package sun.nio.ch; |
| |
| import java.nio.channels.spi.AsynchronousChannelProvider; |
| import java.io.IOException; |
| import java.util.HashSet; |
| import java.util.Iterator; |
| import java.util.concurrent.ArrayBlockingQueue; |
| import java.util.concurrent.RejectedExecutionException; |
| import java.util.concurrent.atomic.AtomicInteger; |
| import java.util.concurrent.locks.ReentrantLock; |
| import jdk.internal.misc.Unsafe; |
| |
| /** |
| * AsynchronousChannelGroup implementation based on the AIX pollset framework. |
| */ |
| final class AixPollPort |
| extends Port |
| { |
| private static final Unsafe unsafe = Unsafe.getUnsafe(); |
| |
| static { |
| IOUtil.load(); |
| init(); |
| } |
| |
| /** |
| * struct pollfd { |
| * int fd; |
| * short events; |
| * short revents; |
| * } |
| */ |
| private static final int SIZEOF_POLLFD = eventSize(); |
| private static final int OFFSETOF_EVENTS = eventsOffset(); |
| private static final int OFFSETOF_REVENTS = reventsOffset(); |
| private static final int OFFSETOF_FD = fdOffset(); |
| |
| // opcodes |
| private static final int PS_ADD = 0x0; |
| private static final int PS_MOD = 0x1; |
| private static final int PS_DELETE = 0x2; |
| |
| // maximum number of events to poll at a time |
| private static final int MAX_POLL_EVENTS = 512; |
| |
| // pollset ID |
| private final int pollset; |
| |
| // true if port is closed |
| private boolean closed; |
| |
| // socket pair used for wakeup |
| private final int sp[]; |
| |
| // socket pair used to indicate pending pollsetCtl calls |
| // Background info: pollsetCtl blocks when another thread is in a pollsetPoll call. |
| private final int ctlSp[]; |
| |
| // number of wakeups pending |
| private final AtomicInteger wakeupCount = new AtomicInteger(); |
| |
| // address of the poll array passed to pollset_poll |
| private final long address; |
| |
| // encapsulates an event for a channel |
| static class Event { |
| final PollableChannel channel; |
| final int events; |
| |
| Event(PollableChannel channel, int events) { |
| this.channel = channel; |
| this.events = events; |
| } |
| |
| PollableChannel channel() { return channel; } |
| int events() { return events; } |
| } |
| |
| // queue of events for cases that a polling thread dequeues more than one |
| // event |
| private final ArrayBlockingQueue<Event> queue; |
| private final Event NEED_TO_POLL = new Event(null, 0); |
| private final Event EXECUTE_TASK_OR_SHUTDOWN = new Event(null, 0); |
| private final Event CONTINUE_AFTER_CTL_EVENT = new Event(null, 0); |
| |
| // encapsulates a pollset control event for a file descriptor |
| static class ControlEvent { |
| final int fd; |
| final int events; |
| final boolean removeOnly; |
| int error = 0; |
| |
| ControlEvent(int fd, int events, boolean removeOnly) { |
| this.fd = fd; |
| this.events = events; |
| this.removeOnly = removeOnly; |
| } |
| |
| int fd() { return fd; } |
| int events() { return events; } |
| boolean removeOnly() { return removeOnly; } |
| int error() { return error; } |
| void setError(int error) { this.error = error; } |
| } |
| |
| // queue of control events that need to be processed |
| // (this object is also used for synchronization) |
| private final HashSet<ControlEvent> controlQueue = new HashSet<ControlEvent>(); |
| |
| // lock used to check whether a poll operation is ongoing |
| private final ReentrantLock controlLock = new ReentrantLock(); |
| |
| AixPollPort(AsynchronousChannelProvider provider, ThreadPool pool) |
| throws IOException |
| { |
| super(provider, pool); |
| |
| // open pollset |
| this.pollset = pollsetCreate(); |
| |
| // create socket pair for wakeup mechanism |
| int[] sv = new int[2]; |
| try { |
| socketpair(sv); |
| // register one end with pollset |
| pollsetCtl(pollset, PS_ADD, sv[0], Net.POLLIN); |
| } catch (IOException x) { |
| pollsetDestroy(pollset); |
| throw x; |
| } |
| this.sp = sv; |
| |
| // create socket pair for pollset control mechanism |
| sv = new int[2]; |
| try { |
| socketpair(sv); |
| // register one end with pollset |
| pollsetCtl(pollset, PS_ADD, sv[0], Net.POLLIN); |
| } catch (IOException x) { |
| pollsetDestroy(pollset); |
| throw x; |
| } |
| this.ctlSp = sv; |
| |
| // allocate the poll array |
| this.address = allocatePollArray(MAX_POLL_EVENTS); |
| |
| // create the queue and offer the special event to ensure that the first |
| // threads polls |
| this.queue = new ArrayBlockingQueue<Event>(MAX_POLL_EVENTS); |
| this.queue.offer(NEED_TO_POLL); |
| } |
| |
| AixPollPort start() { |
| startThreads(new EventHandlerTask()); |
| return this; |
| } |
| |
| /** |
| * Release all resources |
| */ |
| private void implClose() { |
| synchronized (this) { |
| if (closed) |
| return; |
| closed = true; |
| } |
| freePollArray(address); |
| close0(sp[0]); |
| close0(sp[1]); |
| close0(ctlSp[0]); |
| close0(ctlSp[1]); |
| pollsetDestroy(pollset); |
| } |
| |
| private void wakeup() { |
| if (wakeupCount.incrementAndGet() == 1) { |
| // write byte to socketpair to force wakeup |
| try { |
| interrupt(sp[1]); |
| } catch (IOException x) { |
| throw new AssertionError(x); |
| } |
| } |
| } |
| |
| @Override |
| void executeOnHandlerTask(Runnable task) { |
| synchronized (this) { |
| if (closed) |
| throw new RejectedExecutionException(); |
| offerTask(task); |
| wakeup(); |
| } |
| } |
| |
| @Override |
| void shutdownHandlerTasks() { |
| /* |
| * If no tasks are running then just release resources; otherwise |
| * write to the one end of the socketpair to wakeup any polling threads. |
| */ |
| int nThreads = threadCount(); |
| if (nThreads == 0) { |
| implClose(); |
| } else { |
| // send interrupt to each thread |
| while (nThreads-- > 0) { |
| wakeup(); |
| } |
| } |
| } |
| |
| // invoke by clients to register a file descriptor |
| @Override |
| void startPoll(int fd, int events) { |
| queueControlEvent(new ControlEvent(fd, events, false)); |
| } |
| |
| // Callback method for implementations that need special handling when fd is removed |
| @Override |
| protected void preUnregister(int fd) { |
| queueControlEvent(new ControlEvent(fd, 0, true)); |
| } |
| |
| // Add control event into queue and wait for completion. |
| // In case the control lock is free, this method also tries to apply the control change directly. |
| private void queueControlEvent(ControlEvent ev) { |
| // pollsetCtl blocks when a poll call is ongoing. This is very probable. |
| // Therefore we let the polling thread do the pollsetCtl call. |
| synchronized (controlQueue) { |
| controlQueue.add(ev); |
| // write byte to socketpair to force wakeup |
| try { |
| interrupt(ctlSp[1]); |
| } catch (IOException x) { |
| throw new AssertionError(x); |
| } |
| do { |
| // Directly empty queue if no poll call is ongoing. |
| if (controlLock.tryLock()) { |
| try { |
| processControlQueue(); |
| } finally { |
| controlLock.unlock(); |
| } |
| } else { |
| try { |
| // Do not starve in case the polling thread returned before |
| // we could write to ctlSp[1] but the polling thread did not |
| // release the control lock until we checked. Therefore, use |
| // a timed wait for the time being. |
| controlQueue.wait(100); |
| } catch (InterruptedException e) { |
| // ignore exception and try again |
| } |
| } |
| } while (controlQueue.contains(ev)); |
| } |
| if (ev.error() != 0) { |
| throw new AssertionError(); |
| } |
| } |
| |
| // Process all events currently stored in the control queue. |
| private void processControlQueue() { |
| synchronized (controlQueue) { |
| // On Aix it is only possible to set the event |
| // bits on the first call of pollsetCtl. Later |
| // calls only add bits, but cannot remove them. |
| // Therefore, we always remove the file |
| // descriptor ignoring the error and then add it. |
| Iterator<ControlEvent> iter = controlQueue.iterator(); |
| while (iter.hasNext()) { |
| ControlEvent ev = iter.next(); |
| pollsetCtl(pollset, PS_DELETE, ev.fd(), 0); |
| if (!ev.removeOnly()) { |
| ev.setError(pollsetCtl(pollset, PS_MOD, ev.fd(), ev.events())); |
| } |
| iter.remove(); |
| } |
| controlQueue.notifyAll(); |
| } |
| } |
| |
| /* |
| * Task to process events from pollset and dispatch to the channel's |
| * onEvent handler. |
| * |
| * Events are retreived from pollset in batch and offered to a BlockingQueue |
| * where they are consumed by handler threads. A special "NEED_TO_POLL" |
| * event is used to signal one consumer to re-poll when all events have |
| * been consumed. |
| */ |
| private class EventHandlerTask implements Runnable { |
| private Event poll() throws IOException { |
| try { |
| for (;;) { |
| int n; |
| controlLock.lock(); |
| try { |
| n = pollsetPoll(pollset, address, MAX_POLL_EVENTS); |
| } finally { |
| controlLock.unlock(); |
| } |
| /* |
| * 'n' events have been read. Here we map them to their |
| * corresponding channel in batch and queue n-1 so that |
| * they can be handled by other handler threads. The last |
| * event is handled by this thread (and so is not queued). |
| */ |
| fdToChannelLock.readLock().lock(); |
| try { |
| while (n-- > 0) { |
| long eventAddress = getEvent(address, n); |
| int fd = getDescriptor(eventAddress); |
| |
| // To emulate one shot semantic we need to remove |
| // the file descriptor here. |
| if (fd != sp[0] && fd != ctlSp[0]) { |
| synchronized (controlQueue) { |
| pollsetCtl(pollset, PS_DELETE, fd, 0); |
| } |
| } |
| |
| // wakeup |
| if (fd == sp[0]) { |
| if (wakeupCount.decrementAndGet() == 0) { |
| // no more wakeups so drain pipe |
| drain1(sp[0]); |
| } |
| |
| // queue special event if there are more events |
| // to handle. |
| if (n > 0) { |
| queue.offer(EXECUTE_TASK_OR_SHUTDOWN); |
| continue; |
| } |
| return EXECUTE_TASK_OR_SHUTDOWN; |
| } |
| |
| // wakeup to process control event |
| if (fd == ctlSp[0]) { |
| synchronized (controlQueue) { |
| drain1(ctlSp[0]); |
| processControlQueue(); |
| } |
| if (n > 0) { |
| continue; |
| } |
| return CONTINUE_AFTER_CTL_EVENT; |
| } |
| |
| PollableChannel channel = fdToChannel.get(fd); |
| if (channel != null) { |
| int events = getRevents(eventAddress); |
| Event ev = new Event(channel, events); |
| |
| // n-1 events are queued; This thread handles |
| // the last one except for the wakeup |
| if (n > 0) { |
| queue.offer(ev); |
| } else { |
| return ev; |
| } |
| } |
| } |
| } finally { |
| fdToChannelLock.readLock().unlock(); |
| } |
| } |
| } finally { |
| // to ensure that some thread will poll when all events have |
| // been consumed |
| queue.offer(NEED_TO_POLL); |
| } |
| } |
| |
| public void run() { |
| Invoker.GroupAndInvokeCount myGroupAndInvokeCount = |
| Invoker.getGroupAndInvokeCount(); |
| final boolean isPooledThread = (myGroupAndInvokeCount != null); |
| boolean replaceMe = false; |
| Event ev; |
| try { |
| for (;;) { |
| // reset invoke count |
| if (isPooledThread) |
| myGroupAndInvokeCount.resetInvokeCount(); |
| |
| try { |
| replaceMe = false; |
| ev = queue.take(); |
| |
| // no events and this thread has been "selected" to |
| // poll for more. |
| if (ev == NEED_TO_POLL) { |
| try { |
| ev = poll(); |
| } catch (IOException x) { |
| x.printStackTrace(); |
| return; |
| } |
| } |
| } catch (InterruptedException x) { |
| continue; |
| } |
| |
| // contine after we processed a control event |
| if (ev == CONTINUE_AFTER_CTL_EVENT) { |
| continue; |
| } |
| |
| // handle wakeup to execute task or shutdown |
| if (ev == EXECUTE_TASK_OR_SHUTDOWN) { |
| Runnable task = pollTask(); |
| if (task == null) { |
| // shutdown request |
| return; |
| } |
| // run task (may throw error/exception) |
| replaceMe = true; |
| task.run(); |
| continue; |
| } |
| |
| // process event |
| try { |
| ev.channel().onEvent(ev.events(), isPooledThread); |
| } catch (Error x) { |
| replaceMe = true; throw x; |
| } catch (RuntimeException x) { |
| replaceMe = true; throw x; |
| } |
| } |
| } finally { |
| // last handler to exit when shutdown releases resources |
| int remaining = threadExit(this, replaceMe); |
| if (remaining == 0 && isShutdown()) { |
| implClose(); |
| } |
| } |
| } |
| } |
| |
| /** |
| * Allocates a poll array to handle up to {@code count} events. |
| */ |
| private static long allocatePollArray(int count) { |
| return unsafe.allocateMemory(count * SIZEOF_POLLFD); |
| } |
| |
| /** |
| * Free a poll array |
| */ |
| private static void freePollArray(long address) { |
| unsafe.freeMemory(address); |
| } |
| |
| /** |
| * Returns event[i]; |
| */ |
| private static long getEvent(long address, int i) { |
| return address + (SIZEOF_POLLFD*i); |
| } |
| |
| /** |
| * Returns event->fd |
| */ |
| private static int getDescriptor(long eventAddress) { |
| return unsafe.getInt(eventAddress + OFFSETOF_FD); |
| } |
| |
| /** |
| * Returns event->events |
| */ |
| private static int getEvents(long eventAddress) { |
| return unsafe.getChar(eventAddress + OFFSETOF_EVENTS); |
| } |
| |
| /** |
| * Returns event->revents |
| */ |
| private static int getRevents(long eventAddress) { |
| return unsafe.getChar(eventAddress + OFFSETOF_REVENTS); |
| } |
| |
| // -- Native methods -- |
| |
| private static native void init(); |
| |
| private static native int eventSize(); |
| |
| private static native int eventsOffset(); |
| |
| private static native int reventsOffset(); |
| |
| private static native int fdOffset(); |
| |
| private static native int pollsetCreate() throws IOException; |
| |
| private static native int pollsetCtl(int pollset, int opcode, int fd, int events); |
| |
| private static native int pollsetPoll(int pollset, long pollAddress, int numfds) |
| throws IOException; |
| |
| private static native void pollsetDestroy(int pollset); |
| |
| private static native void socketpair(int[] sv) throws IOException; |
| |
| private static native void interrupt(int fd) throws IOException; |
| |
| private static native void drain1(int fd) throws IOException; |
| |
| private static native void close0(int fd); |
| } |
