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8266369: (se) Add wepoll based Selector

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Reviewed-by: chegar, michaelm, vtewari, dfuchs, bpb
This commit is contained in:
Alan Bateman 2021-05-08 07:14:36 +00:00
parent ff77ca8bd4
commit be4f25b0c8
23 changed files with 3234 additions and 102 deletions
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276
src/java.base/windows/classes/sun/nio/ch/WEPollSelectorImpl.java Normal file
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/*
* Copyright (c) 2020, 2021, 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. 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.io.FileDescriptor;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.ClosedSelectorException;
import java.nio.channels.Pipe;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.spi.SelectorProvider;
import java.util.ArrayDeque;
import java.util.Deque;
import java.util.HashMap;
import java.util.Map;
import java.util.function.Consumer;
import static sun.nio.ch.WEPoll.*;
/**
* Windows wepoll based Selector implementation
*/
class WEPollSelectorImpl extends SelectorImpl {
// maximum number of events to poll in one call to epoll_wait
private static final int NUM_EPOLLEVENTS = 256;
// wepoll handle
private final long eph;
// address of epoll_event array when polling with epoll_wait
private final long pollArrayAddress;
// maps SOCKET to selection key, synchronize on selector
private final Map<Integer, SelectionKeyImpl> fdToKey = new HashMap<>();
// pending new registrations/updates, queued by setEventOps
private final Object updateLock = new Object();
private final Deque<SelectionKeyImpl> updateKeys = new ArrayDeque<>();
// interrupt/wakeup
private final Object interruptLock = new Object();
private boolean interruptTriggered;
private final PipeImpl pipe;
private final int fd0Val, fd1Val;
WEPollSelectorImpl(SelectorProvider sp) throws IOException {
super(sp);
this.eph = WEPoll.create();
this.pollArrayAddress = WEPoll.allocatePollArray(NUM_EPOLLEVENTS);
// wakeup support
try {
this.pipe = new PipeImpl(sp, /*buffering*/ false);
} catch (IOException ioe) {
WEPoll.freePollArray(pollArrayAddress);
WEPoll.close(eph);
throw ioe;
}
this.fd0Val = pipe.source().getFDVal();
this.fd1Val = pipe.sink().getFDVal();
// register one end of the pipe for wakeups
WEPoll.ctl(eph, EPOLL_CTL_ADD, fd0Val, WEPoll.EPOLLIN);
}
private void ensureOpen() {
if (!isOpen())
throw new ClosedSelectorException();
}
@Override
protected int doSelect(Consumer<SelectionKey> action, long timeout)
throws IOException
{
assert Thread.holdsLock(this);
// epoll_wait timeout is int
int to = (int) Math.min(timeout, Integer.MAX_VALUE);
boolean blocking = (to != 0);
int numEntries;
processUpdateQueue();
processDeregisterQueue();
try {
begin(blocking);
numEntries = WEPoll.wait(eph, pollArrayAddress, NUM_EPOLLEVENTS, to);
} finally {
end(blocking);
}
processDeregisterQueue();
return processEvents(numEntries, action);
}
/**
* Process changes to the interest ops.
*/
private void processUpdateQueue() {
assert Thread.holdsLock(this);
synchronized (updateLock) {
SelectionKeyImpl ski;
while ((ski = updateKeys.pollFirst()) != null) {
if (ski.isValid()) {
int fd = ski.getFDVal();
// add to fdToKey if needed
SelectionKeyImpl previous = fdToKey.putIfAbsent(fd, ski);
assert (previous == null) || (previous == ski);
int newOps = ski.translateInterestOps();
int registeredOps = ski.registeredEvents();
if (newOps != registeredOps) {
if (newOps == 0) {
// remove from epoll
WEPoll.ctl(eph, EPOLL_CTL_DEL, fd, 0);
} else {
int events = toEPollEvents(newOps);
if (registeredOps == 0) {
// add to epoll
WEPoll.ctl(eph, EPOLL_CTL_ADD, fd, events);
} else {
// modify events
WEPoll.ctl(eph, EPOLL_CTL_MOD, fd, events);
}
}
ski.registeredEvents(newOps);
}
}
}
}
}
/**
* Process the polled events.
* If the interrupt fd has been selected, drain it and clear the interrupt.
*/
private int processEvents(int numEntries, Consumer<SelectionKey> action)
throws IOException
{
assert Thread.holdsLock(this);
boolean interrupted = false;
int numKeysUpdated = 0;
for (int i = 0; i < numEntries; i++) {
long event = WEPoll.getEvent(pollArrayAddress, i);
int fd = WEPoll.getDescriptor(event);
if (fd == fd0Val) {
interrupted = true;
} else {
SelectionKeyImpl ski = fdToKey.get(fd);
if (ski != null) {
int events = WEPoll.getEvents(event);
if ((events & WEPoll.EPOLLPRI) != 0) {
Net.discardOOB(ski.getFD());
}
int rOps = toReadyOps(events);
numKeysUpdated += processReadyEvents(rOps, ski, action);
}
}
}
if (interrupted) {
clearInterrupt();
}
return numKeysUpdated;
}
@Override
protected void implClose() throws IOException {
assert !isOpen() && Thread.holdsLock(this);
// prevent further wakeup
synchronized (interruptLock) {
interruptTriggered = true;
}
// close the epoll port and free resources
WEPoll.close(eph);
WEPoll.freePollArray(pollArrayAddress);
pipe.sink().close();
pipe.source().close();
}
@Override
protected void implDereg(SelectionKeyImpl ski) throws IOException {
assert !ski.isValid() && Thread.holdsLock(this);
int fd = ski.getFDVal();
if (fdToKey.remove(fd) != null) {
if (ski.registeredEvents() != 0) {
WEPoll.ctl(eph, EPOLL_CTL_DEL, fd, 0);
ski.registeredEvents(0);
}
} else {
assert ski.registeredEvents() == 0;
}
}
@Override
public void setEventOps(SelectionKeyImpl ski) {
ensureOpen();
synchronized (updateLock) {
updateKeys.addLast(ski);
}
}
@Override
public Selector wakeup() {
synchronized (interruptLock) {
if (!interruptTriggered) {
try {
IOUtil.write1(fd1Val, (byte) 0);
} catch (IOException ioe) {
throw new InternalError(ioe);
}
interruptTriggered = true;
}
}
return this;
}
private void clearInterrupt() throws IOException {
synchronized (interruptLock) {
IOUtil.drain(fd0Val);
interruptTriggered = false;
}
}
/**
* Maps interest ops to epoll events
*/
private static int toEPollEvents(int ops) {
int events = EPOLLPRI;
if ((ops & Net.POLLIN) != 0)
events |= EPOLLIN;
if ((ops & (Net.POLLOUT | Net.POLLCONN)) != 0)
events |= EPOLLOUT;
return events;
}
/**
* Map epoll events to ready ops
*/
private static int toReadyOps(int events) {
int ops = 0;
if ((events & WEPoll.EPOLLIN) != 0) ops |= Net.POLLIN;
if ((events & WEPoll.EPOLLOUT) != 0) ops |= (Net.POLLOUT | Net.POLLCONN);
if ((events & WEPoll.EPOLLHUP) != 0) ops |= Net.POLLHUP;
if ((events & WEPoll.EPOLLERR) != 0) ops |= Net.POLLERR;
return ops;
}
}