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/*
* @test
* @bug 4413752
* @summary Test SuspendThread with RawMonitor enter.
* @requires vm.jvmti
* @library /test/lib
* @compile SuspendWithRawMonitorEnter.java
* @run main/othervm/native -agentlib:SuspendWithRawMonitorEnter SuspendWithRawMonitorEnter
*/
import java.io.PrintStream;
//
// main blocker contender resumer
// ================= ================ =================== ================
// launch blocker
// <launch returns> blocker running
// launch contender enter threadLock
// <launch returns> wait for notify contender running
// launch resumer : block on threadLock
// <launch returns> : : resumer running
// suspend contender : <suspended> wait for notify
// <ready to test> : : :
// : : : :
// notify blocker wait finishes : :
// notify resumer exit threadLock : wait finishes
// join blocker : : enter threadLock
// <join returns> blocker exits <resumed> resume contender
// join resumer : exit threadLock
// <join returns> enter threadLock resumer exits
// join contender exit threadLock
// <join returns> contender exits
//
public class SuspendWithRawMonitorEnter {
private static final String AGENT_LIB = "SuspendWithRawMonitorEnter";
private static final int exit_delta = 95;
private static final int DEF_TIME_MAX = 60; // default max # secs to test
private static final int JOIN_MAX = 30; // max # secs to wait for join
public static final int TS_INIT = 1; // initial testState
public static final int TS_BLOCKER_RUNNING = 2; // blocker is running
public static final int TS_CONTENDER_RUNNING = 3; // contender is running
public static final int TS_RESUMER_RUNNING = 4; // resumer is running
public static final int TS_CALL_SUSPEND = 5; // call suspend on contender
public static final int TS_DONE_BLOCKING = 6; // done blocking threadLock
public static final int TS_READY_TO_RESUME = 7; // ready to resume contender
public static final int TS_CALL_RESUME = 8; // call resume on contender
public static final int TS_CONTENDER_DONE = 9; // contender has run; done
public static Object barrierLaunch = new Object(); // controls thread launch
public static Object barrierBlocker = new Object(); // controls blocker
public static Object barrierResumer = new Object(); // controls resumer
public static long count = 0;
public static boolean printDebug = false;
public volatile static int testState;
private static void log(String msg) { System.out.println(msg); }
native static int createRawMonitor();
native static int destroyRawMonitor();
native static int suspendThread(SuspendWithRawMonitorEnterWorker thr);
public static void main(String[] args) throws Exception {
try {
System.loadLibrary(AGENT_LIB);
log("Loaded library: " + AGENT_LIB);
} catch (UnsatisfiedLinkError ule) {
log("Failed to load library: " + AGENT_LIB);
log("java.library.path: " + System.getProperty("java.library.path"));
throw ule;
}
int timeMax = 0;
if (args.length == 0) {
timeMax = DEF_TIME_MAX;
} else {
int argIndex = 0;
int argsLeft = args.length;
if (args[0].equals("-p")) {
printDebug = true;
argIndex = 1;
argsLeft--;
}
if (argsLeft == 0) {
timeMax = DEF_TIME_MAX;
} else if (argsLeft == 1) {
try {
timeMax = Integer.parseUnsignedInt(args[argIndex]);
} catch (NumberFormatException nfe) {
System.err.println("'" + args[argIndex] +
"': invalid timeMax value.");
usage();
}
} else {
usage();
}
}
System.exit(run(timeMax, System.out) + exit_delta);
}
public static void logDebug(String mesg) {
if (printDebug) {
System.err.println(Thread.currentThread().getName() + ": " + mesg);
}
}
public static void usage() {
System.err.println("Usage: " + AGENT_LIB + " [-p][time_max]");
System.err.println("where:");
System.err.println(" -p ::= print debug info");
System.err.println(" time_max ::= max looping time in seconds");
System.err.println(" (default is " + DEF_TIME_MAX +
" seconds)");
System.exit(1);
}
public static int run(int timeMax, PrintStream out) {
return (new SuspendWithRawMonitorEnter()).doWork(timeMax, out);
}
public static void checkTestState(int exp) {
if (testState != exp) {
System.err.println("Failure at " + count + " loops.");
throw new InternalError("Unexpected test state value: "
+ "expected=" + exp + " actual=" + testState);
}
}
public int doWork(int timeMax, PrintStream out) {
SuspendWithRawMonitorEnterWorker blocker; // blocker thread
SuspendWithRawMonitorEnterWorker contender; // contender thread
SuspendWithRawMonitorEnterWorker resumer; // resumer thread
int retCode = createRawMonitor();
if (retCode != 0) {
throw new RuntimeException("error in JVMTI CreateRawMonitor: " +
"retCode=" + retCode);
}
logDebug("created threadLock");
System.out.println("About to execute for " + timeMax + " seconds.");
long start_time = System.currentTimeMillis();
while (System.currentTimeMillis() < start_time + (timeMax * 1000)) {
count++;
testState = TS_INIT; // starting the test loop
// launch the blocker thread
synchronized (barrierLaunch) {
blocker = new SuspendWithRawMonitorEnterWorker("blocker");
blocker.start();
while (testState != TS_BLOCKER_RUNNING) {
try {
barrierLaunch.wait(0); // wait until it is running
} catch (InterruptedException ex) {
}
}
}
// launch the contender thread
synchronized (barrierLaunch) {
contender = new SuspendWithRawMonitorEnterWorker("contender");
contender.start();
while (testState != TS_CONTENDER_RUNNING) {
try {
barrierLaunch.wait(0); // wait until it is running
} catch (InterruptedException ex) {
}
}
}
// launch the resumer thread
synchronized (barrierLaunch) {
resumer = new SuspendWithRawMonitorEnterWorker("resumer", contender);
resumer.start();
while (testState != TS_RESUMER_RUNNING) {
try {
barrierLaunch.wait(0); // wait until it is running
} catch (InterruptedException ex) {
}
}
}
//
// Known bug: We don't have a way of knowing when the
// contender thread contends on the threadLock. If we
// suspend it before it has blocked, then we don't really
// have contention. However, the resumer thread won't
// resume the contender thread until after it has grabbed
// the threadLock so we don't have a lock order problem
// and the test won't fall over.
//
// We reduce the size of this timing window by launching
// the resumer thread after the contender thread. So the
// contender thread has all the setup time for the resumer
// thread to call JVM/TI RawMonitorEnter() and block on
// the threadLock.
//
checkTestState(TS_RESUMER_RUNNING);
testState = TS_CALL_SUSPEND;
logDebug("before suspend thread");
retCode = suspendThread(contender);
if (retCode != 0) {
throw new RuntimeException("error in JVMTI SuspendThread: " +
"retCode=" + retCode);
}
logDebug("suspended thread");
//
// At this point, all of the child threads are running
// and we can get to meat of the test:
//
// - suspended threadLock contender
// - a threadLock exit in the blocker thread
// - a threadLock enter in the resumer thread
// - resumption of the contender thread
// - a threadLock enter in the freshly resumed contender thread
//
synchronized (barrierBlocker) {
checkTestState(TS_CALL_SUSPEND);
// tell blocker thread to exit threadLock
testState = TS_DONE_BLOCKING;
barrierBlocker.notify();
}
synchronized (barrierResumer) {
// tell resumer thread to resume contender thread
testState = TS_READY_TO_RESUME;
barrierResumer.notify();
// Can't call checkTestState() here because the
// resumer thread may have already resumed the
// contender thread.
}
try {
blocker.join();
resumer.join(JOIN_MAX * 1000);
if (resumer.isAlive()) {
System.err.println("Failure at " + count + " loops.");
throw new InternalError("resumer thread is stuck");
}
contender.join(JOIN_MAX * 1000);
if (contender.isAlive()) {
System.err.println("Failure at " + count + " loops.");
throw new InternalError("contender thread is stuck");
}
} catch (InterruptedException ex) {
}
checkTestState(TS_CONTENDER_DONE);
}
retCode = destroyRawMonitor();
if (retCode != 0) {
throw new RuntimeException("error in JVMTI DestroyRawMonitor: " +
"retCode=" + retCode);
}
logDebug("destroyed threadLock");
System.out.println("Executed " + count + " loops in " + timeMax +
" seconds.");
return 0;
}
}
class SuspendWithRawMonitorEnterWorker extends Thread {
private SuspendWithRawMonitorEnterWorker target; // target for resume operation
public SuspendWithRawMonitorEnterWorker(String name) {
super(name);
}
public SuspendWithRawMonitorEnterWorker(String name, SuspendWithRawMonitorEnterWorker target) {
super(name);
this.target = target;
}
native static int rawMonitorEnter();
native static int rawMonitorExit();
native static int resumeThread(SuspendWithRawMonitorEnterWorker thr);
public void run() {
SuspendWithRawMonitorEnter.logDebug("thread running");
//
// Launch the blocker thread:
// - grabs threadLock
// - holds threadLock until we tell it let go
// - releases threadLock
//
int retCode;
if (getName().equals("blocker")) {
// grab threadLock before we tell main we are running
SuspendWithRawMonitorEnter.logDebug("before enter threadLock");
retCode = rawMonitorEnter();
if (retCode != 0) {
throw new RuntimeException("error in JVMTI RawMonitorEnter: " +
"retCode=" + retCode);
}
SuspendWithRawMonitorEnter.logDebug("enter threadLock");
SuspendWithRawMonitorEnter.checkTestState(SuspendWithRawMonitorEnter.TS_INIT);
// recursive entry
SuspendWithRawMonitorEnter.logDebug("before recursive enter threadLock");
retCode = rawMonitorEnter();
if (retCode != 0) {
throw new RuntimeException("error in JVMTI RawMonitorEnter: " +
"retCode=" + retCode);
}
SuspendWithRawMonitorEnter.logDebug("recursive enter threadLock");
SuspendWithRawMonitorEnter.logDebug("before recursive exit threadLock");
retCode = rawMonitorExit();
if (retCode != 0) {
throw new RuntimeException("error in JVMTI RawMonitorExit: " +
"retCode=" + retCode);
}
SuspendWithRawMonitorEnter.logDebug("recursive exit threadLock");
synchronized(SuspendWithRawMonitorEnter.barrierBlocker) {
synchronized(SuspendWithRawMonitorEnter.barrierLaunch) {
// tell main we are running
SuspendWithRawMonitorEnter.testState = SuspendWithRawMonitorEnter.TS_BLOCKER_RUNNING;
SuspendWithRawMonitorEnter.barrierLaunch.notify();
}
SuspendWithRawMonitorEnter.logDebug("thread waiting");
// TS_READY_TO_RESUME is set right after TS_DONE_BLOCKING
// is set so either can get the blocker thread out of
// this wait() wrapper:
while (SuspendWithRawMonitorEnter.testState != SuspendWithRawMonitorEnter.TS_DONE_BLOCKING &&
SuspendWithRawMonitorEnter.testState != SuspendWithRawMonitorEnter.TS_READY_TO_RESUME) {
try {
// wait for main to tell us when to exit threadLock
SuspendWithRawMonitorEnter.barrierBlocker.wait(0);
} catch (InterruptedException ex) {
}
}
SuspendWithRawMonitorEnter.logDebug("before exit threadLock");
retCode = rawMonitorExit();
if (retCode != 0) {
throw new RuntimeException("error in JVMTI RawMonitorExit: "
+ "retCode=" + retCode);
}
SuspendWithRawMonitorEnter.logDebug("exit threadLock");
}
}
//
// Launch the contender thread:
// - tries to grab the threadLock
// - grabs threadLock
// - releases threadLock
//
else if (getName().equals("contender")) {
synchronized(SuspendWithRawMonitorEnter.barrierLaunch) {
// tell main we are running
SuspendWithRawMonitorEnter.testState = SuspendWithRawMonitorEnter.TS_CONTENDER_RUNNING;
SuspendWithRawMonitorEnter.barrierLaunch.notify();
}
SuspendWithRawMonitorEnter.logDebug("before enter threadLock");
retCode = rawMonitorEnter();
if (retCode != 0) {
throw new RuntimeException("error in JVMTI RawMonitorEnter: " +
"retCode=" + retCode);
}
SuspendWithRawMonitorEnter.logDebug("enter threadLock");
SuspendWithRawMonitorEnter.checkTestState(SuspendWithRawMonitorEnter.TS_CALL_RESUME);
SuspendWithRawMonitorEnter.testState = SuspendWithRawMonitorEnter.TS_CONTENDER_DONE;
SuspendWithRawMonitorEnter.logDebug("before exit threadLock");
retCode = rawMonitorExit();
if (retCode != 0) {
throw new RuntimeException("error in JVMTI RawMonitorExit: " +
"retCode=" + retCode);
}
SuspendWithRawMonitorEnter.logDebug("exit threadLock");
}
//
// Launch the resumer thread:
// - tries to grab the threadLock (should not block!)
// - grabs threadLock
// - resumes the contended thread
// - releases threadLock
//
else if (getName().equals("resumer")) {
synchronized(SuspendWithRawMonitorEnter.barrierResumer) {
synchronized(SuspendWithRawMonitorEnter.barrierLaunch) {
// tell main we are running
SuspendWithRawMonitorEnter.testState = SuspendWithRawMonitorEnter.TS_RESUMER_RUNNING;
SuspendWithRawMonitorEnter.barrierLaunch.notify();
}
SuspendWithRawMonitorEnter.logDebug("thread waiting");
while (SuspendWithRawMonitorEnter.testState != SuspendWithRawMonitorEnter.TS_READY_TO_RESUME) {
try {
// wait for main to tell us when to continue
SuspendWithRawMonitorEnter.barrierResumer.wait(0);
} catch (InterruptedException ex) {
}
}
}
SuspendWithRawMonitorEnter.logDebug("before enter threadLock");
retCode = rawMonitorEnter();
if (retCode != 0) {
throw new RuntimeException("error in JVMTI RawMonitorEnter: " +
"retCode=" + retCode);
}
SuspendWithRawMonitorEnter.logDebug("enter threadLock");
SuspendWithRawMonitorEnter.checkTestState(SuspendWithRawMonitorEnter.TS_READY_TO_RESUME);
SuspendWithRawMonitorEnter.testState = SuspendWithRawMonitorEnter.TS_CALL_RESUME;
// resume the contender thread so contender.join() can work
SuspendWithRawMonitorEnter.logDebug("before resume thread");
retCode = resumeThread(target);
if (retCode != 0) {
throw new RuntimeException("error in JVMTI ResumeThread: " +
"retCode=" + retCode);
}
SuspendWithRawMonitorEnter.logDebug("resumed thread");
SuspendWithRawMonitorEnter.logDebug("before exit threadLock");
retCode = rawMonitorExit();
if (retCode != 0) {
throw new RuntimeException("error in JVMTI RawMonitorExit: " +
"retCode=" + retCode);
}
SuspendWithRawMonitorEnter.logDebug("exit threadLock");
}
}
}