/*
* Generate the contents of a THST chunk. The data encompasses all known
* threads.
*
* Response has:
* (1b) header len
* (1b) bytes per entry
* (2b) thread count
* Then, for each thread:
* (4b) threadId
* (1b) thread status
* (4b) tid
* (4b) utime
* (4b) stime
* (1b) is daemon?
*
* The length fields exist in anticipation of adding additional fields
* without wanting to break ddms or bump the full protocol version. I don't
* think it warrants full versioning. They might be extraneous and could
* be removed from a future version.
*
* Returns a new byte[] with the data inside, or NULL on failure. The
* caller must call dvmReleaseTrackedAlloc() on the array.
*/
ArrayObject* dvmDdmGenerateThreadStats(void)
{
const int kHeaderLen = 4;
const int kBytesPerEntry = 18;
dvmLockThreadList(NULL);
Thread* thread;
int threadCount = 0;
for (thread = gDvm.threadList; thread != NULL; thread = thread->next)
threadCount++;
/*
* Create a temporary buffer. We can't perform heap allocation with
* the thread list lock held (could cause a GC). The output is small
* enough to sit on the stack.
*/
int bufLen = kHeaderLen + threadCount * kBytesPerEntry;
u1 tmpBuf[bufLen];
u1* buf = tmpBuf;
set1(buf+0, kHeaderLen);
set1(buf+1, kBytesPerEntry);
set2BE(buf+2, (u2) threadCount);
buf += kHeaderLen;
pid_t pid = getpid();
for (thread = gDvm.threadList; thread != NULL; thread = thread->next) {
unsigned long utime, stime;
bool isDaemon;
if (!getThreadStats(pid, thread->systemTid, &utime, &stime)) {
// failed; drop in empty values
utime = stime = 0;
}
isDaemon = dvmGetFieldBoolean(thread->threadObj,
gDvm.offJavaLangThread_daemon);
set4BE(buf+0, thread->threadId);
set1(buf+4, thread->status);
set4BE(buf+5, thread->systemTid);
set4BE(buf+9, utime);
set4BE(buf+13, stime);
set1(buf+17, isDaemon);
buf += kBytesPerEntry;
}
dvmUnlockThreadList();
/*
* Create a byte array to hold the data.
*/
ArrayObject* arrayObj = dvmAllocPrimitiveArray('B', bufLen, ALLOC_DEFAULT);
if (arrayObj != NULL)
memcpy(arrayObj->contents, tmpBuf, bufLen);
return arrayObj;
}
/*
* void interrupt()
*
* Interrupt a thread that is waiting (or is about to wait) on a monitor.
*/
static void Dalvik_java_lang_VMThread_interrupt(const u4* args, JValue* pResult)
{
Object* thisPtr = (Object*) args[0];
Thread* thread;
dvmLockThreadList(NULL);
thread = dvmGetThreadFromThreadObject(thisPtr);
if (thread != NULL)
dvmThreadInterrupt(thread);
dvmUnlockThreadList();
RETURN_VOID();
}
/*
* Visits all threads on the thread list.
*/
static void visitThreads(RootVisitor *visitor, void *arg)
{
Thread *thread;
assert(visitor != NULL);
dvmLockThreadList(dvmThreadSelf());
thread = gDvm.threadList;
while (thread) {
visitThread(visitor, thread, arg);
thread = thread->next;
}
dvmUnlockThreadList();
}
/*
* Find the specified thread and return its stack trace as an array of
* StackTraceElement objects.
*/
ArrayObject* dvmDdmGetStackTraceById(u4 threadId)
{
Thread* self = dvmThreadSelf();
Thread* thread;
int* traceBuf;
dvmLockThreadList(self);
for (thread = gDvm.threadList; thread != NULL; thread = thread->next) {
if (thread->threadId == threadId)
break;
}
if (thread == NULL) {
LOGI("dvmDdmGetStackTraceById: threadid=%d not found\n", threadId);
dvmUnlockThreadList();
return NULL;
}
/*
* Suspend the thread, pull out the stack trace, then resume the thread
* and release the thread list lock. If we're being asked to examine
* our own stack trace, skip the suspend/resume.
*/
int stackDepth = -1;
if (thread != self)
dvmSuspendThread(thread);
traceBuf = dvmFillInStackTraceRaw(thread, &stackDepth);
if (thread != self)
dvmResumeThread(thread);
dvmUnlockThreadList();
/*
* Convert the raw buffer into an array of StackTraceElement.
*/
ArrayObject* trace = dvmGetStackTraceRaw(traceBuf, stackDepth);
free(traceBuf);
return trace;
}
/*
* void getStatus()
*
* Gets the Thread status. Result is in VM terms, has to be mapped to
* Thread.State by interpreted code.
*/
static void Dalvik_java_lang_VMThread_getStatus(const u4* args, JValue* pResult)
{
Object* thisPtr = (Object*) args[0];
Thread* thread;
int result;
dvmLockThreadList(NULL);
thread = dvmGetThreadFromThreadObject(thisPtr);
if (thread != NULL)
result = thread->status;
else
result = THREAD_ZOMBIE; // assume it used to exist and is now gone
dvmUnlockThreadList();
RETURN_INT(result);
}
/*
* void setPriority(int newPriority)
*
* Alter the priority of the specified thread. "newPriority" will range
* from Thread.MIN_PRIORITY to Thread.MAX_PRIORITY (1-10), with "normal"
* threads at Thread.NORM_PRIORITY (5).
*/
static void Dalvik_java_lang_VMThread_setPriority(const u4* args,
JValue* pResult)
{
Object* thisPtr = (Object*) args[0];
int newPriority = args[1];
Thread* thread;
dvmLockThreadList(NULL);
thread = dvmGetThreadFromThreadObject(thisPtr);
if (thread != NULL)
dvmChangeThreadPriority(thread, newPriority);
//dvmDumpAllThreads(false);
dvmUnlockThreadList();
RETURN_VOID();
}
/*
* boolean isInterrupted()
*
* Determine if the specified thread has been interrupted. Does not clear
* the flag.
*/
static void Dalvik_java_lang_VMThread_isInterrupted(const u4* args,
JValue* pResult)
{
Object* thisPtr = (Object*) args[0];
Thread* thread;
bool interrupted;
dvmLockThreadList(NULL);
thread = dvmGetThreadFromThreadObject(thisPtr);
if (thread != NULL)
interrupted = thread->interrupted;
else
interrupted = false;
dvmUnlockThreadList();
RETURN_BOOLEAN(interrupted);
}
/*
* boolean holdsLock(Object object)
*
* Returns whether the current thread has a monitor lock on the specific
* object.
*/
static void Dalvik_java_lang_VMThread_holdsLock(const u4* args, JValue* pResult)
{
Object* thisPtr = (Object*) args[0];
Object* object = (Object*) args[1];
Thread* thread;
if (object == NULL) {
dvmThrowNullPointerException("object == null");
RETURN_VOID();
}
dvmLockThreadList(NULL);
thread = dvmGetThreadFromThreadObject(thisPtr);
int result = dvmHoldsLock(thread, object);
dvmUnlockThreadList();
RETURN_BOOLEAN(result);
}
/*
* Turn thread notification on or off.
*/
void dvmDdmSetThreadNotification(bool enable)
{
/*
* We lock the thread list to avoid sending duplicate events or missing
* a thread change. We should be okay holding this lock while sending
* the messages out. (We have to hold it while accessing a live thread.)
*/
dvmLockThreadList(NULL);
gDvm.ddmThreadNotification = enable;
if (enable) {
Thread* thread;
for (thread = gDvm.threadList; thread != NULL; thread = thread->next) {
//LOGW("notify %d\n", thread->threadId);
dvmDdmSendThreadNotification(thread, true);
}
}
dvmUnlockThreadList();
}
/*
* void nameChanged(String newName)
*
* The name of the target thread has changed. We may need to alert DDMS.
*/
static void Dalvik_java_lang_VMThread_nameChanged(const u4* args,
JValue* pResult)
{
Object* thisPtr = (Object*) args[0];
StringObject* nameStr = (StringObject*) args[1];
Thread* thread;
int threadId = -1;
/* get the thread's ID */
dvmLockThreadList(NULL);
thread = dvmGetThreadFromThreadObject(thisPtr);
if (thread != NULL)
threadId = thread->threadId;
dvmUnlockThreadList();
dvmDdmSendThreadNameChange(threadId, nameStr);
//char* str = dvmCreateCstrFromString(nameStr);
//ALOGI("UPDATE: threadid=%d now '%s'", threadId, str);
//free(str);
RETURN_VOID();
}
/*
* Dump stack frames, starting from the specified frame and moving down.
*
* Each frame holds a pointer to the currently executing method, and the
* saved program counter from the caller ("previous" frame). This means
* we don't have the PC for the current method on the stack, which is
* pretty reasonable since it's in the "PC register" for the VM. Because
* exceptions need to show the correct line number we actually *do* have
* an updated version in the fame's "xtra.currentPc", but it's unreliable.
*
* Note "framePtr" could be NULL in rare circumstances.
*/
static void dumpFrames(const DebugOutputTarget* target, void* framePtr,
Thread* thread)
{
const StackSaveArea* saveArea;
const Method* method;
int checkCount = 0;
const u2* currentPc = NULL;
bool first = true;
/*
* We call functions that require us to be holding the thread list lock.
* It's probable that the caller has already done so, but it's not
* guaranteed. If it's not locked, lock it now.
*/
bool needThreadUnlock = dvmTryLockThreadList();
/*
* The "currentPc" is updated whenever we execute an instruction that
* might throw an exception. Show it here.
*/
if (framePtr != NULL && !dvmIsBreakFrame((u4*)framePtr)) {
saveArea = SAVEAREA_FROM_FP(framePtr);
if (saveArea->xtra.currentPc != NULL)
currentPc = saveArea->xtra.currentPc;
}
while (framePtr != NULL) {
saveArea = SAVEAREA_FROM_FP(framePtr);
method = saveArea->method;
if (dvmIsBreakFrame((u4*)framePtr)) {
//dvmPrintDebugMessage(target, " (break frame)\n");
} else {
int relPc;
if (currentPc != NULL)
relPc = currentPc - saveArea->method->insns;
else
relPc = -1;
std::string methodName(dvmHumanReadableMethod(method, false));
if (dvmIsNativeMethod(method)) {
dvmPrintDebugMessage(target, " at %s(Native Method)\n",
methodName.c_str());
} else {
dvmPrintDebugMessage(target, " at %s(%s:%s%d)\n",
methodName.c_str(), dvmGetMethodSourceFile(method),
(relPc >= 0 && first) ? "~" : "",
relPc < 0 ? -1 : dvmLineNumFromPC(method, relPc));
}
if (first) {
/*
* Decorate WAIT and MONITOR threads with some detail on
* the first frame.
*
* warning: wait status not stable, even in suspend
*/
if (thread->status == THREAD_WAIT ||
thread->status == THREAD_TIMED_WAIT)
{
Monitor* mon = thread->waitMonitor;
Object* obj = dvmGetMonitorObject(mon);
if (obj != NULL) {
Thread* joinThread = NULL;
if (obj->clazz == gDvm.classJavaLangVMThread) {
joinThread = dvmGetThreadFromThreadObject(obj);
}
if (joinThread == NULL) {
joinThread = dvmGetObjectLockHolder(obj);
}
printWaitMessage(target, "on", obj, joinThread);
}
} else if (thread->status == THREAD_MONITOR) {
Object* obj;
Thread* owner;
if (extractMonitorEnterObject(thread, &obj, &owner)) {
printWaitMessage(target, "to lock", obj, owner);
}
}
}
}
/*
* Get saved PC for previous frame. There's no savedPc in a "break"
* frame, because that represents native or interpreted code
* invoked by the VM. The saved PC is sitting in the "PC register",
* a local variable on the native stack.
*/
currentPc = saveArea->savedPc;
first = false;
if (saveArea->prevFrame != NULL && saveArea->prevFrame <= framePtr) {
ALOGW("Warning: loop in stack trace at frame %d (%p -> %p)",
checkCount, framePtr, saveArea->prevFrame);
break;
}
framePtr = saveArea->prevFrame;
checkCount++;
if (checkCount > 300) {
dvmPrintDebugMessage(target,
" ***** printed %d frames, not showing any more\n",
checkCount);
break;
}
}
if (needThreadUnlock) {
dvmUnlockThreadList();
}
}
static void resetCodeCache(void)
{
Thread* thread;
u8 startTime = dvmGetRelativeTimeUsec();
int inJit = 0;
int byteUsed = gDvmJit.codeCacheByteUsed;
/* If any thread is found stuck in the JIT state, don't reset the cache */
dvmLockThreadList(NULL);
for (thread = gDvm.threadList; thread != NULL; thread = thread->next) {
/*
* Crawl the stack to wipe out the returnAddr field so that
* 1) the soon-to-be-deleted code in the JIT cache won't be used
* 2) or the thread stuck in the JIT land will soon return
* to the interpreter land
*/
crawlDalvikStack(thread, false);
if (thread->inJitCodeCache) {
inJit++;
}
/* Cancel any ongoing trace selection */
dvmDisableSubMode(thread, kSubModeJitTraceBuild);
}
dvmUnlockThreadList();
if (inJit) {
ALOGD("JIT code cache reset delayed (%d bytes %d/%d)",
gDvmJit.codeCacheByteUsed, gDvmJit.numCodeCacheReset,
++gDvmJit.numCodeCacheResetDelayed);
return;
}
/* Lock the mutex to clean up the work queue */
dvmLockMutex(&gDvmJit.compilerLock);
/* Update the translation cache version */
gDvmJit.cacheVersion++;
/* Drain the work queue to free the work orders */
while (workQueueLength()) {
CompilerWorkOrder work = workDequeue();
free(work.info);
}
/* Reset the JitEntry table contents to the initial unpopulated state */
dvmJitResetTable();
UNPROTECT_CODE_CACHE(gDvmJit.codeCache, gDvmJit.codeCacheByteUsed);
/*
* Wipe out the code cache content to force immediate crashes if
* stale JIT'ed code is invoked.
*/
dvmCompilerCacheClear((char *) gDvmJit.codeCache + gDvmJit.templateSize,
gDvmJit.codeCacheByteUsed - gDvmJit.templateSize);
dvmCompilerCacheFlush((intptr_t) gDvmJit.codeCache,
(intptr_t) gDvmJit.codeCache + gDvmJit.codeCacheByteUsed);
PROTECT_CODE_CACHE(gDvmJit.codeCache, gDvmJit.codeCacheByteUsed);
/* Reset the current mark of used bytes to the end of template code */
gDvmJit.codeCacheByteUsed = gDvmJit.templateSize;
gDvmJit.numCompilations = 0;
/* Reset the work queue */
memset(gDvmJit.compilerWorkQueue, 0,
sizeof(CompilerWorkOrder) * COMPILER_WORK_QUEUE_SIZE);
gDvmJit.compilerWorkEnqueueIndex = gDvmJit.compilerWorkDequeueIndex = 0;
gDvmJit.compilerQueueLength = 0;
/* Reset the IC patch work queue */
dvmLockMutex(&gDvmJit.compilerICPatchLock);
gDvmJit.compilerICPatchIndex = 0;
dvmUnlockMutex(&gDvmJit.compilerICPatchLock);
/*
* Reset the inflight compilation address (can only be done in safe points
* or by the compiler thread when its thread state is RUNNING).
*/
gDvmJit.inflightBaseAddr = NULL;
/* All clear now */
gDvmJit.codeCacheFull = false;
dvmUnlockMutex(&gDvmJit.compilerLock);
ALOGD("JIT code cache reset in %lld ms (%d bytes %d/%d)",
(dvmGetRelativeTimeUsec() - startTime) / 1000,
byteUsed, ++gDvmJit.numCodeCacheReset,
gDvmJit.numCodeCacheResetDelayed);
}
/* Make sure that the HeapWorker thread hasn't spent an inordinate
* amount of time inside a finalizer.
*
* Aborts the VM if the thread appears to be wedged.
*
* The caller must hold the heapWorkerLock to guarantee an atomic
* read of the watchdog values.
*/
void dvmAssertHeapWorkerThreadRunning()
{
if (gDvm.gcHeap->heapWorkerCurrentObject != NULL) {
static const u8 HEAP_WORKER_WATCHDOG_TIMEOUT = 10*1000*1000LL; // 10sec
u8 heapWorkerInterpStartTime = gDvm.gcHeap->heapWorkerInterpStartTime;
u8 now = dvmGetRelativeTimeUsec();
u8 delta = now - heapWorkerInterpStartTime;
if (delta > HEAP_WORKER_WATCHDOG_TIMEOUT &&
(gDvm.debuggerActive || gDvm.nativeDebuggerActive))
{
/*
* Debugger suspension can block the thread indefinitely. For
* best results we should reset this explicitly whenever the
* HeapWorker thread is resumed. Unfortunately this is also
* affected by native debuggers, and we have no visibility
* into how they're manipulating us. So, we ignore the
* watchdog and just reset the timer.
*/
LOGI("Debugger is attached -- suppressing HeapWorker watchdog\n");
gDvm.gcHeap->heapWorkerInterpStartTime = now; /* reset timer */
} else if (delta > HEAP_WORKER_WATCHDOG_TIMEOUT) {
/*
* Before we give up entirely, see if maybe we're just not
* getting any CPU time because we're stuck in a background
* process group. If we successfully move the thread into the
* foreground we'll just leave it there (it doesn't do anything
* if the process isn't GCing).
*/
dvmLockThreadList(NULL);
Thread* thread = dvmGetThreadByHandle(gDvm.heapWorkerHandle);
dvmUnlockThreadList();
if (thread != NULL) {
int priChangeFlags, threadPrio;
SchedPolicy threadPolicy;
priChangeFlags = dvmRaiseThreadPriorityIfNeeded(thread,
&threadPrio, &threadPolicy);
if (priChangeFlags != 0) {
LOGI("HeapWorker watchdog expired, raising priority"
" and retrying\n");
gDvm.gcHeap->heapWorkerInterpStartTime = now;
return;
}
}
char* desc = dexProtoCopyMethodDescriptor(
&gDvm.gcHeap->heapWorkerCurrentMethod->prototype);
LOGE("HeapWorker is wedged: %lldms spent inside %s.%s%s\n",
delta / 1000,
gDvm.gcHeap->heapWorkerCurrentObject->clazz->descriptor,
gDvm.gcHeap->heapWorkerCurrentMethod->name, desc);
free(desc);
dvmDumpAllThreads(true);
/* try to get a debuggerd dump from the target thread */
dvmNukeThread(thread);
/* abort the VM */
dvmAbort();
} else if (delta > HEAP_WORKER_WATCHDOG_TIMEOUT / 2) {
char* desc = dexProtoCopyMethodDescriptor(
&gDvm.gcHeap->heapWorkerCurrentMethod->prototype);
LOGW("HeapWorker may be wedged: %lldms spent inside %s.%s%s\n",
delta / 1000,
gDvm.gcHeap->heapWorkerCurrentObject->clazz->descriptor,
gDvm.gcHeap->heapWorkerCurrentMethod->name, desc);
free(desc);
}
}
}