jdk-sandbox: comparison src/java.base/windows/classes/sun/nio/ch/WindowsSelectorImpl.java

equal deleted inserted replaced

-:aaba7cc40951
+:84e08e00c29c
 import java.util.Deque;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.function.Consumer;
+import jdk.internal.misc.Unsafe;
 /**
 * A multi-threaded implementation of Selector for Windows.
 *
 * @author Konstantin Kladko
 * @author Mark Reinhold
 */
 class WindowsSelectorImpl extends SelectorImpl {
+private static final Unsafe unsafe = Unsafe.getUnsafe();
+private static int addressSize = unsafe.addressSize();
+private static int dependsArch(int value32, int value64) {
+return (addressSize == 4) ? value32 : value64;
+}
 // Initial capacity of the poll array
 private final int INIT_CAP = 8;
 // Maximum number of sockets for select().
 // Should be INIT_CAP times a power of 2
 private static final int MAX_SELECTABLE_FDS = 1024;
+// Size of FD_SET struct to allocate a buffer for it in SubSelector,
+// aligned to 8 bytes on 64-bit:
+// struct { unsigned int fd_count; SOCKET fd_array[MAX_SELECTABLE_FDS]; }.
+private static final long SIZEOF_FD_SET = dependsArch(
+4 + MAX_SELECTABLE_FDS * 4,      // SOCKET = unsigned int
+4 + MAX_SELECTABLE_FDS * 8 + 4); // SOCKET = unsigned __int64
 // The list of SelectableChannels serviced by this Selector. Every mod
 // MAX_SELECTABLE_FDS entry is bogus, to align this array with the poll
 // array,  where the corresponding entry is occupied by the wakeupSocket
 private SelectionKeyImpl[] channelArray = new SelectionKeyImpl[INIT_CAP];
 // The first element of each array is the number of selected sockets.
 // Other elements are file descriptors of selected sockets.
 private final int[] readFds = new int [MAX_SELECTABLE_FDS + 1];
 private final int[] writeFds = new int [MAX_SELECTABLE_FDS + 1];
 private final int[] exceptFds = new int [MAX_SELECTABLE_FDS + 1];
+// Buffer for readfds, writefds and exceptfds structs that are passed
+// to native select().
+private final long fdsBuffer = unsafe.allocateMemory(SIZEOF_FD_SET * 3);
 private SubSelector() {
 this.pollArrayIndex = 0; // main thread
 }
 }
 private int poll() throws IOException{ // poll for the main thread
 return poll0(pollWrapper.pollArrayAddress,
 Math.min(totalChannels, MAX_SELECTABLE_FDS),
-readFds, writeFds, exceptFds, timeout);
+readFds, writeFds, exceptFds, timeout, fdsBuffer);
 }
 private int poll(int index) throws IOException {
 // poll for helper threads
 return  poll0(pollWrapper.pollArrayAddress +
 (pollArrayIndex * PollArrayWrapper.SIZE_POLLFD),
 Math.min(MAX_SELECTABLE_FDS,
 totalChannels - (index + 1) * MAX_SELECTABLE_FDS),
-readFds, writeFds, exceptFds, timeout);
+readFds, writeFds, exceptFds, timeout, fdsBuffer);
 }
 private native int poll0(long pollAddress, int numfds,
-int[] readFds, int[] writeFds, int[] exceptFds, long timeout);
+int[] readFds, int[] writeFds, int[] exceptFds, long timeout, long fdsBuffer);
 private int processSelectedKeys(long updateCount, Consumer<SelectionKey> action) {
 int numKeysUpdated = 0;
 numKeysUpdated += processFDSet(updateCount, action, readFds,
 Net.POLLIN,
 numKeysUpdated++;
 }
 }
 return numKeysUpdated;
 }
+private void freeFDSetBuffer() {
+unsafe.freeMemory(fdsBuffer);
+}
 }
 // Represents a helper thread used for select.
 private final class SelectThread extends Thread {
 private final int index; // index of this thread
 }
 public void run() {
 while (true) { // poll loop
 // wait for the start of poll. If this thread has become
 // redundant, then exit.
-if (startLock.waitForStart(this))
+if (startLock.waitForStart(this)) {
+subSelector.freeFDSetBuffer();
 return;
+}
 // call poll()
 try {
 subSelector.poll(index);
 } catch (IOException e) {
 // Save this exception and let other threads finish.
 // Make all remaining helper threads exit
 for (SelectThread t: threads)
 t.makeZombie();
 startLock.startThreads();
+subSelector.freeFDSetBuffer();
 }
 @Override
 protected void implRegister(SelectionKeyImpl ski) {
 ensureOpen();

branch	unixdomainchannels
changeset 59004	84e08e00c29c
parent 58801	119ac9128c1b
parent 58999	6bc29ebe053e