SelfSuspendDisablerTest.java

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/*
 * @test
 * @summary Test verifies that selfsuspend doesn' block unmount by VTMTDisabler
 * @requires vm.continuations
 * @library /test/lib
 * @compile --enable-preview -source ${jdk.version} SelfSuspendDisablerTest.java
 * @run main/othervm/native --enable-preview -agentlib:SelfSuspendDisablerTest SelfSuspendDisablerTest
 */

public class SelfSuspendDisablerTest {

    static {
        System.loadLibrary("SelfSuspendDisablerTest");
    }

    // Tested JVM TI thread states
    static final int NEW        = 0;        // No bits are set
    static final int TERMINATED = 2;        // JVMTI_THREAD_STATE_TERMINATED
    static final int RUNNABLE   = 5;        // JVMTI_THREAD_STATE_ALIVE & JVMTI_THREAD_STATE_RUNNABLE
    static final int SUSPENDED  = 0x100005; // RUNNABLE & JVMTI_THREAD_STATE_SUSPENDED

    native static boolean isSuspended(Thread thread);
    native static void selfSuspend();
    native static void resume(Thread thread);
    native static void suspendAllVirtualThreads();
    native static void resumeAllVirtualThreads();
    native static int getThreadState(Thread thread);

    private static void sleep(long millis) {
        try {
            Thread.sleep(millis);
        } catch (InterruptedException ie) {
            // ignore InterruptedException
        }
    }

    private static void testJvmtiThreadState(Thread thread, int expectedState) {
        String kindStr = thread.isVirtual()? "virtual " : "platform";
        int state = getThreadState(thread);

        System.out.printf("Expected %s thread state: %06X got: %06X\n",
                          kindStr, expectedState, state);
        if (state != expectedState) {
            throw new RuntimeException("Test FAILED: Unexpected thread state");
        }
    }

    public static void main(String argv[]) throws Exception {
        Thread t1 = Thread.ofPlatform().factory().newThread(() -> {
            testJvmtiThreadState(Thread.currentThread(), RUNNABLE);
            selfSuspend();
        });
        Thread t2 = Thread.ofVirtual().factory().newThread(() -> {
            testJvmtiThreadState(Thread.currentThread(), RUNNABLE);
            while(!isSuspended(t1)) {
              Thread.yield();
            }
            Thread.yield(); // provoke unmount

            testJvmtiThreadState(t1, SUSPENDED);

            resume(t1);

            suspendAllVirtualThreads();
        });

        testJvmtiThreadState(t1, NEW);
        testJvmtiThreadState(t2, NEW);

        t1.start();
        t2.start();

        while(!isSuspended(t2)) {
            sleep(100);
        }

        testJvmtiThreadState(t2, SUSPENDED);

        resumeAllVirtualThreads();

        t2.join();
        t1.join();

        testJvmtiThreadState(t1, TERMINATED);
        testJvmtiThreadState(t2, TERMINATED);
    }

}