/*
* Grab the lock, but put ourselves into THREAD_VMWAIT if it looks like
* we're going to have to wait on the mutex.
*/
bool dvmLockHeap()
{
if (dvmTryLockMutex(&gDvm.gcHeapLock) != 0) {
Thread *self;
ThreadStatus oldStatus;
self = dvmThreadSelf();
oldStatus = dvmChangeStatus(self, THREAD_VMWAIT);
dvmLockMutex(&gDvm.gcHeapLock);
dvmChangeStatus(self, oldStatus);
}
return true;
}
/*
* Acquires a mutex, transitioning to the VMWAIT state if the mutex is
* held. This allows the thread to suspend while it waits for another
* thread to release the mutex.
*/
static void lockMutex(pthread_mutex_t *mu)
{
Thread *self;
ThreadStatus oldStatus;
assert(mu != NULL);
if (dvmTryLockMutex(mu) != 0) {
self = dvmThreadSelf();
assert(self != NULL);
oldStatus = dvmChangeStatus(self, THREAD_VMWAIT);
dvmLockMutex(mu);
dvmChangeStatus(self, oldStatus);
}
}
static bool tryLockMonitor(Thread* self, Monitor* mon)
{
if (mon->owner == self) {
mon->lockCount++;
return true;
} else {
if (dvmTryLockMutex(&mon->lock) == 0) {
mon->owner = self;
assert(mon->lockCount == 0);
return true;
} else {
return false;
}
}
}
/*
* Grab the lock, but put ourselves into THREAD_VMWAIT if it looks like
* we're going to have to wait on the mutex.
*/
bool dvmLockHeap()
{
/* This is hacked a bit to avoid deadlocks. Basically I don't want a thread
* to suspend itself hodling the heap lock. */
int res;
while ((res = dvmTryLockMutex(&gDvm.gcHeapLock)) != 0) {
assert(res == EBUSY);
Thread *self;
ThreadStatus oldStatus;
self = dvmThreadSelf();
oldStatus = dvmChangeStatus(self, THREAD_VMWAIT);
dvmLockMutex(&gDvm.gcHeapLock);
dvmUnlockMutex(&gDvm.gcHeapLock);
dvmChangeStatus(self, oldStatus);
}
return true;
}
/*
* Grab the lock, but put ourselves into THREAD_VMWAIT if it looks like
* we're going to have to wait on the mutex.
*/
bool dvmLockHeap()
{
if (dvmTryLockMutex(&gDvm.gcHeapLock) != 0) {
Thread *self;
ThreadStatus oldStatus;
self = dvmThreadSelf();
#ifdef FASTIVA
FASTIVA_SUSPEND_STACK_unsafe(self);
#endif
oldStatus = dvmChangeStatus(self, THREAD_VMWAIT);
dvmLockMutex(&gDvm.gcHeapLock);
dvmChangeStatus(self, oldStatus);
#ifdef FASTIVA
FASTIVA_RESUME_STACK_unsafe(self);
#endif
}
return true;
}
/*
* Lock a monitor.
*/
static void lockMonitor(Thread* self, Monitor* mon)
{
ThreadStatus oldStatus;
u4 waitThreshold, samplePercent;
u8 waitStart, waitEnd, waitMs;
if (mon->owner == self) {
mon->lockCount++;
return;
}
if (dvmTryLockMutex(&mon->lock) != 0) {
oldStatus = dvmChangeStatus(self, THREAD_MONITOR);
waitThreshold = gDvm.lockProfThreshold;
if (waitThreshold) {
waitStart = dvmGetRelativeTimeUsec();
}
const Method* currentOwnerMethod = mon->ownerMethod;
u4 currentOwnerPc = mon->ownerPc;
dvmLockMutex(&mon->lock);
if (waitThreshold) {
waitEnd = dvmGetRelativeTimeUsec();
}
dvmChangeStatus(self, oldStatus);
if (waitThreshold) {
waitMs = (waitEnd - waitStart) / 1000;
if (waitMs >= waitThreshold) {
samplePercent = 100;
} else {
samplePercent = 100 * waitMs / waitThreshold;
}
if (samplePercent != 0 && ((u4)rand() % 100 < samplePercent)) {
const char* currentOwnerFileName = "no_method";
u4 currentOwnerLineNumber = 0;
if (currentOwnerMethod != NULL) {
currentOwnerFileName = dvmGetMethodSourceFile(currentOwnerMethod);
if (currentOwnerFileName == NULL) {
currentOwnerFileName = "no_method_file";
}
currentOwnerLineNumber = dvmLineNumFromPC(currentOwnerMethod, currentOwnerPc);
}
logContentionEvent(self, waitMs, samplePercent,
currentOwnerFileName, currentOwnerLineNumber);
}
}
}
mon->owner = self;
assert(mon->lockCount == 0);
// When debugging, save the current monitor holder for future
// acquisition failures to use in sampled logging.
if (gDvm.lockProfThreshold > 0) {
mon->ownerMethod = NULL;
mon->ownerPc = 0;
if (self->interpSave.curFrame == NULL) {
return;
}
const StackSaveArea* saveArea = SAVEAREA_FROM_FP(self->interpSave.curFrame);
if (saveArea == NULL) {
return;
}
mon->ownerMethod = saveArea->method;
mon->ownerPc = (saveArea->xtra.currentPc - saveArea->method->insns);
}
}