Examples with ObjectMonitor com.ibm.j9ddr.vm29.j9.ObjectMonitor used on opensource projects

Example 11 with ObjectMonitor

use of com.ibm.j9ddr.vm29.j9.ObjectMonitor in project openj9 by eclipse.

the class MonitorsCommand method objectsCommand.

private void objectsCommand(FilterOptions filter, PrintStream out) throws DDRInteractiveCommandException {
    try {
        HashSet<ObjectMonitor> monitors = new HashSet<ObjectMonitor>();
        MonitorTableListIterator iterator = new MonitorTableListIterator();
        MonitorTable previousMonitorTable = null;
        StringBuilder builder = new StringBuilder();
        while (iterator.hasNext()) {
            J9ObjectMonitorPointer objectMonitorPointer = iterator.next();
            MonitorTable currentMonitorTable = iterator.currentMonitorTable();
            ObjectMonitor found = tablePrintHelper(filter, builder, objectMonitorPointer);
            if (null != found) {
                monitors.add(found);
            }
            if (!currentMonitorTable.equals(previousMonitorTable) && (builder.length() > 0)) {
                /* Print header for new monitor table */
                if (null != previousMonitorTable) {
                    out.println();
                }
                out.println(iterator.currentMonitorTable().extraInfo());
                previousMonitorTable = currentMonitorTable;
            }
            out.append(builder);
            builder.setLength(0);
        }
        // Don't forget leftover flatlocked monitors on heap, these have no associated table:
        Iterator<ObjectMonitor> flatMonitorIterator = HeapWalker.getFlatLockedMonitors().iterator();
        while (flatMonitorIterator.hasNext()) {
            ObjectMonitor objMon = flatMonitorIterator.next();
            if (!monitors.contains(objMon)) {
                writeObjectMonitorToBuffer(filter, objMon, builder);
            }
        }
        if (builder.length() > 0) {
            out.append("<Flatlocked Monitors on Heap>\n");
            out.append(builder);
        }
    } catch (CorruptDataException e) {
        throw new DDRInteractiveCommandException(e);
    }
}

Example 12 with ObjectMonitor

use of com.ibm.j9ddr.vm29.j9.ObjectMonitor in project openj9 by eclipse.

the class CheckMonitorTable method print.

@Override
public void print() {
    try {
        VoidPointer monitorTableList = VoidPointer.cast(getJavaVM().monitorTableList());
        GCMonitorReferenceIterator monitorReferenceIterator = GCMonitorReferenceIterator.from();
        MonitorTable previousMonitorTable = null;
        ScanFormatter formatter = new ScanFormatter(this, "MonitorTableList", monitorTableList);
        while (monitorReferenceIterator.hasNext()) {
            J9ObjectMonitorPointer objectMonitor = monitorReferenceIterator.next();
            MonitorTable currentMonitorTable = monitorReferenceIterator.currentMonitorTable();
            if (!currentMonitorTable.equals(previousMonitorTable)) {
                if (null != previousMonitorTable) {
                    formatter.endSection();
                }
                formatter.section("MonitorTable", currentMonitorTable.getMonitorTableListEntryPointer());
            }
            J9ThreadAbstractMonitorPointer monitor = J9ThreadAbstractMonitorPointer.cast(objectMonitor.monitor());
            formatter.entry(VoidPointer.cast(monitor.userData()));
            previousMonitorTable = currentMonitorTable;
        }
        if (null != previousMonitorTable) {
            formatter.endSection();
        }
        formatter.end("MonitorTableList", monitorTableList);
    } catch (CorruptDataException e) {
    // TODO: handle exception
    }
}

Example 13 with ObjectMonitor

use of com.ibm.j9ddr.vm29.j9.ObjectMonitor in project openj9 by eclipse.

the class DeadlockUtils method readObjectMonitors.

/**
 * Returns a hash map of Object Pointers to their respective mutex (Object Monitor or System Monitor)
 * @param vm
 * @return
 * @throws CorruptDataException
 */
public static HashMap<J9ObjectPointer, Object> readObjectMonitors(J9JavaVMPointer vm) throws CorruptDataException {
    HashMap<J9ObjectPointer, Object> objectMonitorsMap = new HashMap<J9ObjectPointer, Object>();
    MonitorIterator iterator = new MonitorIterator(vm);
    while (iterator.hasNext()) {
        Object current = iterator.next();
        if (current instanceof ObjectMonitor) {
            ObjectMonitor mon = (ObjectMonitor) current;
            J9ObjectPointer object = mon.getObject();
            objectMonitorsMap.put(object, mon);
        } else if (current instanceof J9ThreadMonitorPointer) {
            // System Monitor
            J9ThreadMonitorPointer mon = (J9ThreadMonitorPointer) current;
            J9ThreadAbstractMonitorPointer lock = J9ThreadAbstractMonitorPointer.cast(mon);
            if (false == lock.userData().eq(0)) {
                // this is an object monitor in the system monitor table
                J9ObjectPointer object = J9ObjectPointer.cast(lock.userData());
                objectMonitorsMap.put(object, mon);
            }
        }
    }
    return objectMonitorsMap;
}

Example 14 with ObjectMonitor

use of com.ibm.j9ddr.vm29.j9.ObjectMonitor in project openj9 by eclipse.

the class DeadlockUtils method findThreadCycle.

/**
 * @param vmThread
 * @param map
 * @throws CorruptDataException
 */
public static void findThreadCycle(J9ThreadPointer aThread, HashMap<Integer, NativeDeadlockGraphNode> deadlocks, HashMap<J9ObjectPointer, Object> objectMonitorsMap) throws CorruptDataException {
    // Based on JavaCoreDumpWriter::findThreadCycle()
    // Can't stack allocate or (safely) re-purpose an object in Java,
    // so we create a new one on each iteration, this is slightly
    // different from what is done in javadump.cpp
    NativeDeadlockGraphNode node = null;
    NativeDeadlockGraphNode prev = null;
    do {
        // Is there an associated J9VMThread?
        J9VMThreadPointer vmThread = J9ThreadHelper.getVMThread(aThread);
        boolean isJavaThread = (null != vmThread) && vmThread.notNull();
        // Enter waiter (blocked) or notify waiter.
        boolean isJavaWaiter = false;
        if (isJavaThread) {
            // There is, so grab all the J9VMThread related information.
            JavaDeadlockGraphNode javaNode = new JavaDeadlockGraphNode();
            javaNode.javaThread = vmThread;
            J9VMThreadPointer owner = null;
            J9ObjectPointer lockObject = null;
            J9ThreadAbstractMonitorPointer lock = null;
            // Functionally equivalent to getVMThreadStateHelper(...) in thrinfo.c
            lockObject = vmThread.blockingEnterObject();
            if ((null != lockObject) && lockObject.notNull()) {
                // This condition hitting means we are in one of the desired states:
                // J9VMTHREAD_STATE_BLOCKED
                // J9VMTHREAD_STATE_WAITING, J9VMTHREAD_STATE_WAITING_TIMED
                // J9VMTHREAD_STATE_PARKED, J9VMTHREAD_STATE_PARKED_TIMED
                isJavaWaiter = true;
                // The original native relies on getVMThreadStateHelper(...)
                // from thrinfo.c to obtain this information, which is analogous
                // to J9VMThreadPointerUtil.getJ9State(...), but we don't actually
                // need all that information.
                Object current = objectMonitorsMap.get(lockObject);
                if (current instanceof ObjectMonitor) {
                    ObjectMonitor mon = (ObjectMonitor) current;
                    owner = mon.getOwner();
                    lock = mon.getInflatedMonitor();
                } else if (current instanceof J9ThreadMonitorPointer) {
                    // System Monitor
                    J9ThreadMonitorPointer mon = (J9ThreadMonitorPointer) current;
                    J9ThreadPointer sysThread = mon.owner();
                    lock = J9ThreadAbstractMonitorPointer.cast(mon);
                    if (sysThread.notNull()) {
                        owner = J9ThreadHelper.getVMThread(sysThread);
                    }
                }
                if ((null == owner) || owner.isNull() || (owner.equals(vmThread))) {
                    // See JAZZ103 63676: There are cases where even if we know there is no
                    // Java deadlock, we should still check for a system deadlock.
                    // We simply deal with this node as a native one from this point on.
                    isJavaWaiter = false;
                } else {
                    // N.B. In the native there are comparisons with J9VMTHREAD_STATE_*
                    // constants as returned by the helper, but here we don't actually need them.
                    javaNode.javaLock = lock;
                    javaNode.lockObject = lockObject;
                    javaNode.cycle = 0;
                    /* Record current thread and update last node */
                    javaNode.nativeThread = vmThread.osThread();
                    deadlocks.put(javaNode.hashCode(), javaNode);
                    if (null != prev) {
                        prev.next = javaNode;
                    }
                    /* Move around the graph */
                    prev = javaNode;
                    /* Peek ahead to see if we're in a possible cycle */
                    prev.next = deadlocks.get(owner.osThread().hashCode());
                    aThread = owner.osThread();
                }
            }
            // Have to keep going for the case of Java thread blocking on system monitor.
            // We have to write the J9Thread info as well.
            node = javaNode;
        }
        if (false == isJavaThread) {
            node = new NativeDeadlockGraphNode();
        }
        // Now get all of the J9Thread fields (even when we are working with a Java thread).
        node.nativeThread = aThread;
        J9ThreadMonitorPointer nativeLock = aThread.monitor();
        J9ThreadPointer owner = null;
        if ((null == nativeLock) || nativeLock.isNull()) {
            if (false == isJavaThread) {
                return;
            }
        } else {
            node.nativeLock = nativeLock;
            owner = nativeLock.owner();
        }
        // to change the pointers, otherwise we have to set them up.
        if (false == isJavaWaiter) {
            deadlocks.put(node.hashCode(), node);
            if (null != prev) {
                prev.next = node;
            }
            if ((null == owner) || owner.isNull() || (owner.equals(aThread))) {
                return;
            } else {
                /* Move around the graph */
                prev = node;
                /* Peek ahead to see if we're in a possible cycle */
                prev.next = deadlocks.get(owner.hashCode());
                aThread = owner;
            }
        }
    } while (// Quit as soon as possible (first node we've already visited).
    null == prev.next);
// The rest of the cycles will be found by multiple calls to findThreadCycle(...)
}