void dvmHeapSourceRegisterNativeAllocation(int bytes)
{
/* If we have just done a GC, ensure that the finalizers are done and update
* the native watermarks.
*/
if (gHs->nativeNeedToRunFinalization) {
dvmRunFinalization();
dvmHeapSourceUpdateMaxNativeFootprint();
gHs->nativeNeedToRunFinalization = false;
}
android_atomic_add(bytes, &gHs->nativeBytesAllocated);
if ((size_t)gHs->nativeBytesAllocated > gHs->nativeFootprintGCWatermark) {
/* The second watermark is higher than the gc watermark. If you hit
* this it means you are allocating native objects faster than the GC
* can keep up with. If this occurs, we do a GC for alloc.
*/
if ((size_t)gHs->nativeBytesAllocated > gHs->nativeFootprintLimit) {
Thread* self = dvmThreadSelf();
dvmRunFinalization();
if (dvmCheckException(self)) {
return;
}
dvmLockHeap();
bool waited = dvmWaitForConcurrentGcToComplete();
dvmUnlockHeap();
if (waited) {
// Just finished a GC, attempt to run finalizers.
dvmRunFinalization();
if (dvmCheckException(self)) {
return;
}
}
// If we still are over the watermark, attempt a GC for alloc and run finalizers.
if ((size_t)gHs->nativeBytesAllocated > gHs->nativeFootprintLimit) {
dvmLockHeap();
dvmWaitForConcurrentGcToComplete();
dvmCollectGarbageInternal(GC_FOR_MALLOC);
dvmUnlockHeap();
dvmRunFinalization();
gHs->nativeNeedToRunFinalization = false;
if (dvmCheckException(self)) {
return;
}
}
/* We have just run finalizers, update the native watermark since
* it is very likely that finalizers released native managed
* allocations.
*/
dvmHeapSourceUpdateMaxNativeFootprint();
} else {
dvmSignalCond(&gHs->gcThreadCond);
}
}
}
/*
* Explicitly initiate garbage collection.
*/
void dvmCollectGarbage(bool collectSoftReferences)
{
dvmLockHeap();
while (gDvm.gcHeap->gcRunning) {
dvmWaitForConcurrentGcToComplete();
}
dvmCollectGarbageInternal(collectSoftReferences, GC_EXPLICIT);
dvmUnlockHeap();
}
/*
* Explicitly initiate garbage collection.
*/
void dvmCollectGarbage()
{
if (gDvm.disableExplicitGc) {
return;
}
dvmLockHeap();
dvmWaitForConcurrentGcToComplete();
dvmCollectGarbageInternal(GC_EXPLICIT);
dvmUnlockHeap();
}
/*
* Removes any growth limits. Allows the user to allocate up to the
* maximum heap size.
*/
void dvmClearGrowthLimit()
{
HS_BOILERPLATE();
dvmLockHeap();
dvmWaitForConcurrentGcToComplete();
gDvm.gcHeap->cardTableLength = gDvm.gcHeap->cardTableMaxLength;
gHs->growthLimit = gHs->maximumSize;
size_t overhead = oldHeapOverhead(gHs, false);
gHs->heaps[0].maximumSize = gHs->maximumSize - overhead;
gHs->heaps[0].limit = gHs->heaps[0].base + gHs->heaps[0].maximumSize;
dvmUnlockHeap();
}
/* Runs the main thread daemmon loop looking for incoming messages from its
* parallel thread on what action it should take. */
static void* thread_daemon(void* pself) {
Thread* self = (Thread*)pself;
while(1) {
u1 event = offReadU1(self);
if(!gDvm.offConnected) {
ALOGI("THREAD %d LOST CONNECTION", self->threadId);
return NULL;
}
ALOGI("THREAD %d GOT EVENT %d", self->threadId, event);
switch(event) {
case OFF_ACTION_RESUME: {
/* We got a resume message, drop back to our caller. */
return NULL;
} break;
case OFF_ACTION_LOCK: {
offPerformLock(self);
} break;
case OFF_ACTION_NOTIFY: {
offPerformNotify(self);
} break;
case OFF_ACTION_BROADCAST: {
offPerformNotifyAll(self);
} break;
case OFF_ACTION_DEX_QUERYDEX: {
offPerformQueryDex(self);
} break;
case OFF_ACTION_SYNC: {
offSyncPull();
offWriteU1(self, 0);
} break;
case OFF_ACTION_INTERRUPT: {
offPerformInterrupt(self);
} break;
case OFF_ACTION_TRIMGC: {
dvmLockHeap();
self->offTrimSignaled = true;
if (gDvm.gcHeap->gcRunning) {
dvmWaitForConcurrentGcToComplete();
}
dvmCollectGarbageInternal(GC_BEFORE_OOM);
self->offTrimSignaled = false;
dvmUnlockHeap();
} break;
case OFF_ACTION_GRABVOL: {
offPerformGrabVolatiles(self);
} break;
case OFF_ACTION_MIGRATE: {
if(offPerformMigrate(self)) {
return NULL;
}
} break;
case OFF_ACTION_CLINIT: {
offPerformClinit(self);
} break;
case OFF_ACTION_DEATH: {
self->offFlagDeath = true;
return NULL;
} break;
default: {
ALOGE("Unknown action %d sent to thread %d",
event, self->threadId);
dvmAbort();
}
}
}
}
/* Try as hard as possible to allocate some memory.
*/
static void *tryMalloc(size_t size)
{
void *ptr;
/* Don't try too hard if there's no way the allocation is
* going to succeed. We have to collect SoftReferences before
* throwing an OOME, though.
*/
if (size >= gDvm.heapGrowthLimit) {
ALOGW("%zd byte allocation exceeds the %zd byte maximum heap size",
size, gDvm.heapGrowthLimit);
ptr = NULL;
goto collect_soft_refs;
}
//TODO: figure out better heuristics
// There will be a lot of churn if someone allocates a bunch of
// big objects in a row, and we hit the frag case each time.
// A full GC for each.
// Maybe we grow the heap in bigger leaps
// Maybe we skip the GC if the size is large and we did one recently
// (number of allocations ago) (watch for thread effects)
// DeflateTest allocs a bunch of ~128k buffers w/in 0-5 allocs of each other
// (or, at least, there are only 0-5 objects swept each time)
ptr = dvmHeapSourceAlloc(size);
if (ptr != NULL) {
return ptr;
}
/*
* The allocation failed. If the GC is running, block until it
* completes and retry.
*/
if (gDvm.gcHeap->gcRunning) {
/*
* The GC is concurrently tracing the heap. Release the heap
* lock, wait for the GC to complete, and retrying allocating.
*/
dvmWaitForConcurrentGcToComplete();
ptr = dvmHeapSourceAlloc(size);
if (ptr != NULL) {
return ptr;
}
}
/*
* Another failure. Our thread was starved or there may be too
* many live objects. Try a foreground GC. This will have no
* effect if the concurrent GC is already running.
*/
gcForMalloc(false);
ptr = dvmHeapSourceAlloc(size);
if (ptr != NULL) {
return ptr;
}
/* Even that didn't work; this is an exceptional state.
* Try harder, growing the heap if necessary.
*/
ptr = dvmHeapSourceAllocAndGrow(size);
if (ptr != NULL) {
size_t newHeapSize;
newHeapSize = dvmHeapSourceGetIdealFootprint();
//TODO: may want to grow a little bit more so that the amount of free
// space is equal to the old free space + the utilization slop for
// the new allocation.
LOGI_HEAP("Grow heap (frag case) to "
"%zu.%03zuMB for %zu-byte allocation",
FRACTIONAL_MB(newHeapSize), size);
return ptr;
}
/* Most allocations should have succeeded by now, so the heap
* is really full, really fragmented, or the requested size is
* really big. Do another GC, collecting SoftReferences this
* time. The VM spec requires that all SoftReferences have
* been collected and cleared before throwing an OOME.
*/
//TODO: wait for the finalizers from the previous GC to finish
collect_soft_refs:
LOGI_HEAP("Forcing collection of SoftReferences for %zu-byte allocation",
size);
gcForMalloc(true);
ptr = dvmHeapSourceAllocAndGrow(size);
if (ptr != NULL) {
return ptr;
}
//TODO: maybe wait for finalizers and try one last time
LOGE_HEAP("Out of memory on a %zd-byte allocation.", size);
//TODO: tell the HeapSource to dump its state
dvmDumpThread(dvmThreadSelf(), false);
return NULL;
}
/*
* The heap worker thread sits quietly until the GC tells it there's work
* to do.
*/
static void* heapWorkerThreadStart(void* arg)
{
Thread *self = dvmThreadSelf();
UNUSED_PARAMETER(arg);
LOGV("HeapWorker thread started (threadid=%d)\n", self->threadId);
/* tell the main thread that we're ready */
lockMutex(&gDvm.heapWorkerLock);
gDvm.heapWorkerReady = true;
dvmSignalCond(&gDvm.heapWorkerCond);
dvmUnlockMutex(&gDvm.heapWorkerLock);
lockMutex(&gDvm.heapWorkerLock);
while (!gDvm.haltHeapWorker) {
struct timespec trimtime;
bool timedwait = false;
/* We're done running interpreted code for now. */
dvmChangeStatus(NULL, THREAD_VMWAIT);
/* Signal anyone who wants to know when we're done. */
dvmBroadcastCond(&gDvm.heapWorkerIdleCond);
/* Trim the heap if we were asked to. */
trimtime = gDvm.gcHeap->heapWorkerNextTrim;
if (trimtime.tv_sec != 0 && trimtime.tv_nsec != 0) {
struct timespec now;
#ifdef HAVE_TIMEDWAIT_MONOTONIC
clock_gettime(CLOCK_MONOTONIC, &now); // relative time
#else
struct timeval tvnow;
gettimeofday(&tvnow, NULL); // absolute time
now.tv_sec = tvnow.tv_sec;
now.tv_nsec = tvnow.tv_usec * 1000;
#endif
if (trimtime.tv_sec < now.tv_sec ||
(trimtime.tv_sec == now.tv_sec &&
trimtime.tv_nsec <= now.tv_nsec))
{
size_t madvisedSizes[HEAP_SOURCE_MAX_HEAP_COUNT];
/*
* Acquire the gcHeapLock. The requires releasing the
* heapWorkerLock before the gcHeapLock is acquired.
* It is possible that the gcHeapLock may be acquired
* during a concurrent GC in which case heapWorkerLock
* is held by the GC and we are unable to make forward
* progress. We avoid deadlock by releasing the
* gcHeapLock and then waiting to be signaled when the
* GC completes. There is no guarantee that the next
* time we are run will coincide with GC inactivity so
* the check and wait must be performed within a loop.
*/
dvmUnlockMutex(&gDvm.heapWorkerLock);
dvmLockHeap();
while (gDvm.gcHeap->gcRunning) {
dvmWaitForConcurrentGcToComplete();
}
dvmLockMutex(&gDvm.heapWorkerLock);
memset(madvisedSizes, 0, sizeof(madvisedSizes));
dvmHeapSourceTrim(madvisedSizes, HEAP_SOURCE_MAX_HEAP_COUNT);
dvmLogMadviseStats(madvisedSizes, HEAP_SOURCE_MAX_HEAP_COUNT);
dvmUnlockHeap();
trimtime.tv_sec = 0;
trimtime.tv_nsec = 0;
gDvm.gcHeap->heapWorkerNextTrim = trimtime;
} else {
timedwait = true;
}
}
/* sleep until signaled */
if (timedwait) {
int cc __attribute__ ((__unused__));
#ifdef HAVE_TIMEDWAIT_MONOTONIC
cc = pthread_cond_timedwait_monotonic(&gDvm.heapWorkerCond,
&gDvm.heapWorkerLock, &trimtime);
#else
cc = pthread_cond_timedwait(&gDvm.heapWorkerCond,
&gDvm.heapWorkerLock, &trimtime);
#endif
assert(cc == 0 || cc == ETIMEDOUT);
} else {
dvmWaitCond(&gDvm.heapWorkerCond, &gDvm.heapWorkerLock);
}
/*
* Return to the running state before doing heap work. This
* will block if the GC has initiated a suspend. We release
* the heapWorkerLock beforehand for the GC to make progress
* and wait to be signaled after the GC completes. There is
* no guarantee that the next time we are run will coincide
* with GC inactivity so the check and wait must be performed
* within a loop.
*/
dvmUnlockMutex(&gDvm.heapWorkerLock);
dvmChangeStatus(NULL, THREAD_RUNNING);
dvmLockHeap();
while (gDvm.gcHeap->gcRunning) {
dvmWaitForConcurrentGcToComplete();
}
dvmLockMutex(&gDvm.heapWorkerLock);
dvmUnlockHeap();
LOGV("HeapWorker is awake\n");
/* Process any events in the queue.
*/
doHeapWork(self);
}
dvmUnlockMutex(&gDvm.heapWorkerLock);
if (gDvm.verboseShutdown)
LOGD("HeapWorker thread shutting down\n");
return NULL;
}