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fix potential sync gap in the test ObjectMonitorUsage
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@sspitsyn
sspitsyn committed Feb 23, 2024
1 parent e9eadc4 commit fd50705
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Showing 2 changed files with 93 additions and 27 deletions.
19 changes: 19 additions & 0 deletions test/hotspot/jtreg/serviceability/jvmti/ObjectMonitorUsage/ObjectMonitorUsage.java
View file
Original file line number Diff line number Diff line change
Expand Up @@ -52,6 +52,8 @@ public class ObjectMonitorUsage {
static Object lockCheck = new Object();

native static int getRes();
native static int waitsToEnter();
native static int setTestedMonitor(Object monitor);
native static void check(Object obj, Thread owner,
int entryCount, int waiterCount, int notifyWaiterCount);

Expand All @@ -63,6 +65,14 @@ static String vtag(boolean isVirtual) {
return isVirtual ? "virtual" : "platform";
}

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

static Thread startTask(int idx, TestTask task, boolean isVirtual, String kind) {
Thread thread = isVirtual ? Thread.ofVirtual().name(kind + "VT" + idx).start(task)
: Thread.ofPlatform().name(kind + "PT" + idx).start(task);
Expand All @@ -85,6 +95,9 @@ static Thread[] startEnteringThreads(boolean isVirtual) {
// the EnteringTask has to be blocked at the lockCheck enter
threads[i] = startTask(i, new EnteringTask(), isVirtual, "Entering");
}
while (waitsToEnter() < NUMBER_OF_ENTERING_THREADS) {
sleep(1);
}
return threads;
}

Expand Down Expand Up @@ -135,6 +148,7 @@ static void test1(boolean isVirtual) {
String vtag = vtag(isVirtual);
log("\n###test1: started " + vtag);

setTestedMonitor(lockCheck);
Thread[] eThreads = null;

synchronized (lockCheck) {
Expand All @@ -155,6 +169,7 @@ static void test1(boolean isVirtual) {
0 /* count of threads waiting to be notified: 0 */);

}
setTestedMonitor(null);
joinThreads(eThreads);
log("###test1: finished " + vtag);
}
Expand All @@ -169,6 +184,7 @@ static void test2(boolean isVirtual) throws Error {
String vtag = vtag(isVirtual);
log("\n###test2: started " + vtag);

setTestedMonitor(lockCheck);
Thread[] wThreads = startWaitingThreads(isVirtual);
Thread[] eThreads = null;

Expand All @@ -185,6 +201,7 @@ static void test2(boolean isVirtual) throws Error {

lockCheck.notifyAll();
}
setTestedMonitor(null);
joinThreads(wThreads);
joinThreads(eThreads);
log("###test2: finished " + vtag);
Expand All @@ -206,6 +223,7 @@ static void test3(boolean isVirtual) throws Error {
String vtag = vtag(isVirtual);
log("\n###test3: started " + vtag);

setTestedMonitor(lockCheck);
Thread[] wThreads = startWaitingThreads(isVirtual);
Thread[] eThreads = null;

Expand Down Expand Up @@ -241,6 +259,7 @@ static void test3(boolean isVirtual) throws Error {
NUMBER_OF_WAITING_THREADS - i - 1);
}
}
setTestedMonitor(null);
joinThreads(wThreads);
joinThreads(eThreads);
log("###test3: finished " + vtag);
Expand Down
101 changes: 74 additions & 27 deletions test/hotspot/jtreg/serviceability/jvmti/ObjectMonitorUsage/libObjectMonitorUsage.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -32,44 +32,71 @@ extern "C" {
#define STATUS_FAILED 2

static jvmtiEnv *jvmti = nullptr;
static jvmtiCapabilities caps;
static jrawMonitorID event_lock = nullptr;
static jint result = PASSED;
static int check_idx = 0;
static int waits_to_enter = 0;
static jobject tested_monitor = nullptr;

static bool is_tested_monitor(JNIEnv *jni, jobject monitor) {
if (tested_monitor == nullptr) {
return false; // tested_monitor was not set yet
}
return jni->IsSameObject(monitor, tested_monitor) == JNI_TRUE;
}

JNIEXPORT void JNICALL
MonitorContendedEnter(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread, jobject monitor) {
RawMonitorLocker rml(jvmti, jni, event_lock);
if (is_tested_monitor(jni, monitor)) {
waits_to_enter++;
}
}

JNIEXPORT void JNICALL
MonitorContendedEntered(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread, jobject monitor) {
RawMonitorLocker rml(jvmti, jni, event_lock);
if (is_tested_monitor(jni, monitor)) {
waits_to_enter--;
}
}


jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
jint res;
jvmtiError err;
jvmtiCapabilities caps;
jvmtiEventCallbacks callbacks;

res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
if (res != JNI_OK || jvmti == nullptr) {
LOG("Wrong result of a valid call to GetEnv !\n");
return JNI_ERR;
}

err = jvmti->GetPotentialCapabilities(&caps);
if (err != JVMTI_ERROR_NONE) {
LOG("(GetPotentialCapabilities) unexpected error: %s (%d)\n",
TranslateError(err), err);
return JNI_ERR;
}
check_jvmti_error(err, "Agent_Initialize: error in JVMTI GetPotentialCapabilities");

err = jvmti->AddCapabilities(&caps);
if (err != JVMTI_ERROR_NONE) {
LOG("(AddCapabilities) unexpected error: %s (%d)\n",
TranslateError(err), err);
return JNI_ERR;
}
check_jvmti_error(err, "Agent_Initialize: error in JVMTI AddCapabilities");

err = jvmti->GetCapabilities(&caps);
if (err != JVMTI_ERROR_NONE) {
LOG("(GetCapabilities) unexpected error: %s (%d)\n",
TranslateError(err), err);
return JNI_ERR;
}
check_jvmti_error(err, "Agent_Initialize: error in JVMTI GetCapabilities");

if (!caps.can_get_monitor_info) {
LOG("Warning: GetObjectMonitorUsage is not implemented\n");
}
if (!caps.can_generate_monitor_events) {
LOG("Warning: Monitor events are not implemented\n");
return JNI_ERR;
}
memset(&callbacks, 0, sizeof(callbacks));
callbacks.MonitorContendedEnter = &MonitorContendedEnter;
callbacks.MonitorContendedEntered = &MonitorContendedEntered;

err = jvmti->SetEventCallbacks(&callbacks, sizeof(jvmtiEventCallbacks));
check_jvmti_error(err, "Agent_Initialize: error in JVMTI SetEventCallbacks");

event_lock = create_raw_monitor(jvmti, "Events Monitor");

return JNI_OK;
}
Expand All @@ -84,13 +111,7 @@ Agent_OnAttach(JavaVM *jvm, char *options, void *reserved) {
return Agent_Initialize(jvm, options, reserved);
}

static void dealloc(JNIEnv *jni, char* mem) {
jvmtiError err = jvmti->Deallocate((unsigned char*)mem);
check_jvmti_status(jni, err, "error in JVMTI Deallocate");
}

static void
print_monitor_info(JNIEnv *jni, jvmtiMonitorUsage &inf) {
static void print_monitor_info(JNIEnv *jni, jvmtiMonitorUsage &inf) {
jvmtiError err;
jvmtiThreadInfo tinf;

Expand All @@ -102,7 +123,7 @@ print_monitor_info(JNIEnv *jni, jvmtiMonitorUsage &inf) {
check_jvmti_status(jni, err, "error in JVMTI GetThreadInfo");
LOG(">>> owner: %s (0x%p)\n",
tinf.name, inf.owner);
dealloc(jni, tinf.name);
deallocate(jvmti, jni, tinf.name);
}
LOG(">>> entry_count: %d\n", inf.entry_count);
LOG(">>> waiter_count: %d\n", inf.waiter_count);
Expand All @@ -115,7 +136,7 @@ print_monitor_info(JNIEnv *jni, jvmtiMonitorUsage &inf) {
check_jvmti_status(jni, err, "error in JVMTI GetThreadInfo");
LOG(">>> %2d: %s (0x%p)\n",
j, tinf.name, inf.waiters[j]);
dealloc(jni, tinf.name);
deallocate(jvmti, jni, tinf.name);
}
}
if (inf.notify_waiter_count > 0) {
Expand All @@ -125,7 +146,7 @@ print_monitor_info(JNIEnv *jni, jvmtiMonitorUsage &inf) {
check_jvmti_status(jni, err, "error in JVMTI GetThreadInfo");
LOG(">>> %2d: %s (0x%p)\n",
j, tinf.name, inf.notify_waiters[j]);
dealloc(jni, tinf.name);
deallocate(jvmti, jni, tinf.name);
}
}
}
Expand Down Expand Up @@ -164,6 +185,32 @@ Java_ObjectMonitorUsage_check(JNIEnv *jni, jclass cls, jobject obj, jthread owne
}
}

JNIEXPORT void JNICALL
Java_ObjectMonitorUsage_setTestedMonitor(JNIEnv *jni, jclass cls, jobject monitor) {
jvmtiError err;
jvmtiEventMode event_mode = (monitor != nullptr) ? JVMTI_ENABLE : JVMTI_DISABLE;

RawMonitorLocker rml(jvmti, jni, event_lock);

if (tested_monitor != nullptr) {
jni->DeleteGlobalRef(tested_monitor);
}
tested_monitor = (monitor != nullptr) ? jni->NewGlobalRef(monitor) : nullptr;
waits_to_enter = 0;

err = jvmti->SetEventNotificationMode(event_mode, JVMTI_EVENT_MONITOR_CONTENDED_ENTER, nullptr);
check_jvmti_status(jni, err, "setTestedMonitor: error in JVMTI SetEventNotificationMode #1");

err = jvmti->SetEventNotificationMode(event_mode, JVMTI_EVENT_MONITOR_CONTENDED_ENTERED, nullptr);
check_jvmti_status(jni, err, "setTestedMonitor: error in JVMTI SetEventNotificationMode #2");
}

JNIEXPORT jint JNICALL
Java_ObjectMonitorUsage_waitsToEnter(JNIEnv *jni, jclass cls) {
RawMonitorLocker rml(jvmti, jni, event_lock);
return waits_to_enter;
}

JNIEXPORT jint JNICALL
Java_ObjectMonitorUsage_getRes(JNIEnv *jni, jclass cls) {
return result;
Expand Down

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