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[#2426] Not cause busy loop when interrupt Thread of AbstractNioSelector

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Motivation:
Because Thread.currentThread().interrupt() will unblock Selector.select() we need to take special care when check if we need to rebuild the Selector. If the unblock was caused by the interrupt() we will clear it and move on as this is most likely a bug in a custom ChannelHandler or a library the user makes use of.

Modification:
Clear the interrupt state of the Thread if the Selector was unblock because of an interrupt and the returned keys was 0.

Result:
No more busy loop caused by Thread.currentThread().interrupt()
This commit is contained in:
Norman Maurer 2014-09-05 10:30:19 +02:00
parent 7569aa6404
commit cfa1074285
1 changed files with 22 additions and 6 deletions
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26
src/main/java/org/jboss/netty/channel/socket/nio/AbstractNioSelector.java
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@ -210,9 +210,8 @@ abstract class AbstractNioSelector implements NioSelector {
try {
long beforeSelect = System.nanoTime();
int selected = select(selector);
if (SelectorUtil.EPOLL_BUG_WORKAROUND && selected == 0 && !wakenupFromLoop && !wakenUp.get()) {
if (selected == 0 && !wakenupFromLoop && !wakenUp.get()) {
long timeBlocked = System.nanoTime() - beforeSelect;
if (timeBlocked < minSelectTimeout) {
boolean notConnected = false;
// loop over all keys as the selector may was unblocked because of a closed channel
@ -232,15 +231,32 @@ abstract class AbstractNioSelector implements NioSelector {
if (notConnected) {
selectReturnsImmediately = 0;
} else {
// returned before the minSelectTimeout elapsed with nothing select.
// this may be the cause of the jdk epoll(..) bug, so increment the counter
// which we use later to see if its really the jdk bug.
if (Thread.interrupted() && !shutdown) {
// Thread was interrupted but NioSelector was not shutdown.
// As this is most likely a bug in the handler of the user or it's client
// library we will log it.
//
// See https://github.com/netty/netty/issues/2426
if (logger.isDebugEnabled()) {
logger.debug("Selector.select() returned prematurely because the I/O thread " +
"has been interrupted. Use shutdown() to shut the NioSelector down.");
}
selectReturnsImmediately = 0;
} else {
// Returned before the minSelectTimeout elapsed with nothing selected.
// This may be because of a bug in JDK NIO Selector provider, so increment the counter
// which we will use later to see if it's really the bug in JDK.
selectReturnsImmediately ++;
}
}
} else {
selectReturnsImmediately = 0;
}
} else {
selectReturnsImmediately = 0;
}
if (SelectorUtil.EPOLL_BUG_WORKAROUND) {
if (selectReturnsImmediately == 1024) {
// The selector returned immediately for 10 times in a row,
// so recreate one selector as it seems like we hit the