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);
}
}
}
static void gcDaemonShutdown()
{
if (gHs->hasGcThread) {
dvmLockMutex(&gHs->gcThreadMutex);
gHs->gcThreadShutdown = true;
dvmSignalCond(&gHs->gcThreadCond);
dvmUnlockMutex(&gHs->gcThreadMutex);
pthread_join(gHs->gcThread, NULL);
}
}
/*
* Wake up the heap worker to let it know that there's work to be done.
*/
void dvmSignalHeapWorker(bool shouldLock)
{
if (shouldLock) {
dvmLockMutex(&gDvm.heapWorkerLock);
}
dvmSignalCond(&gDvm.heapWorkerCond);
if (shouldLock) {
dvmUnlockMutex(&gDvm.heapWorkerLock);
}
}
/*
* Allocates <n> bytes of zeroed data.
*/
void* dvmHeapSourceAlloc(size_t n)
{
HS_BOILERPLATE();
HeapSource *hs = gHs;
Heap* heap = hs2heap(hs);
if (heap->bytesAllocated + n > hs->softLimit) {
/*
* This allocation would push us over the soft limit; act as
* if the heap is full.
*/
LOGV_HEAP("softLimit of %zd.%03zdMB hit for %zd-byte allocation",
FRACTIONAL_MB(hs->softLimit), n);
return NULL;
}
void* ptr = mspace_calloc(heap->msp, 1, n);
if (ptr == NULL) {
return NULL;
}
countAllocation(heap, ptr);
/*
* Check to see if a concurrent GC should be initiated.
*/
if (gDvm.gcHeap->gcRunning || !hs->hasGcThread) {
/*
* The garbage collector thread is already running or has yet
* to be started. Do nothing.
*/
return ptr;
}
if (heap->bytesAllocated > heap->concurrentStartBytes) {
/*
* We have exceeded the allocation threshold. Wake up the
* garbage collector.
*/
dvmSignalCond(&gHs->gcThreadCond);
}
return ptr;
}
static CompilerWorkOrder workDequeue(void)
{
assert(gDvmJit.compilerWorkQueue[gDvmJit.compilerWorkDequeueIndex].kind
!= kWorkOrderInvalid);
CompilerWorkOrder work =
gDvmJit.compilerWorkQueue[gDvmJit.compilerWorkDequeueIndex];
gDvmJit.compilerWorkQueue[gDvmJit.compilerWorkDequeueIndex++].kind =
kWorkOrderInvalid;
if (gDvmJit.compilerWorkDequeueIndex == COMPILER_WORK_QUEUE_SIZE) {
gDvmJit.compilerWorkDequeueIndex = 0;
}
gDvmJit.compilerQueueLength--;
if (gDvmJit.compilerQueueLength == 0) {
dvmSignalCond(&gDvmJit.compilerQueueEmpty);
}
/* Remember the high water mark of the queue length */
if (gDvmJit.compilerQueueLength > gDvmJit.compilerMaxQueued)
gDvmJit.compilerMaxQueued = gDvmJit.compilerQueueLength;
return work;
}
/**
* @brief 取出一条编译工作队列
* @return 返回一个CompilerWorkOrder结构
*/
static CompilerWorkOrder workDequeue(void)
{
/* 断言确定当前工作节点不是无效的 */
assert(gDvmJit.compilerWorkQueue[gDvmJit.compilerWorkDequeueIndex].kind
!= kWorkOrderInvalid);
CompilerWorkOrder work =
gDvmJit.compilerWorkQueue[gDvmJit.compilerWorkDequeueIndex]; /* 取出当前的工作节点 */
gDvmJit.compilerWorkQueue[gDvmJit.compilerWorkDequeueIndex++].kind =
kWorkOrderInvalid; /* 设置当前的工作节点类型为无效的并且索引增加 */
/* 如果索引到达工作队列最大值则索引重新设置为0 */
if (gDvmJit.compilerWorkDequeueIndex == COMPILER_WORK_QUEUE_SIZE) {
gDvmJit.compilerWorkDequeueIndex = 0;
}
gDvmJit.compilerQueueLength--; /* 长度递减 */
if (gDvmJit.compilerQueueLength == 0) {
dvmSignalCond(&gDvmJit.compilerQueueEmpty);
}
/* Remember the high water mark of the queue length */
if (gDvmJit.compilerQueueLength > gDvmJit.compilerMaxQueued)
gDvmJit.compilerMaxQueued = gDvmJit.compilerQueueLength;
return work;
}
/*
* Allocates <n> bytes of zeroed data.
*/
void* dvmHeapSourceAlloc(size_t n)
{
HS_BOILERPLATE();
HeapSource *hs = gHs;
Heap* heap = hs2heap(hs);
if (heap->bytesAllocated + n > hs->softLimit) {
/*
* This allocation would push us over the soft limit; act as
* if the heap is full.
*/
LOGV_HEAP("softLimit of %zd.%03zdMB hit for %zd-byte allocation",
FRACTIONAL_MB(hs->softLimit), n);
return NULL;
}
void* ptr;
if (gDvm.lowMemoryMode) {
/* This is only necessary because mspace_calloc always memsets the
* allocated memory to 0. This is bad for memory usage since it leads
* to dirty zero pages. If low memory mode is enabled, we use
* mspace_malloc which doesn't memset the allocated memory and madvise
* the page aligned region back to the kernel.
*/
ptr = mspace_malloc(heap->msp, n);
if (ptr == NULL) {
return NULL;
}
uintptr_t zero_begin = (uintptr_t)ptr;
uintptr_t zero_end = (uintptr_t)ptr + n;
/* Calculate the page aligned region.
*/
uintptr_t begin = ALIGN_UP_TO_PAGE_SIZE(zero_begin);
uintptr_t end = zero_end & ~(uintptr_t)(SYSTEM_PAGE_SIZE - 1);
/* If our allocation spans more than one page, we attempt to madvise.
*/
if (begin < end) {
/* madvise the page aligned region to kernel.
*/
madvise((void*)begin, end - begin, MADV_DONTNEED);
/* Zero the region after the page aligned region.
*/
memset((void*)end, 0, zero_end - end);
/* Zero out the region before the page aligned region.
*/
zero_end = begin;
}
memset((void*)zero_begin, 0, zero_end - zero_begin);
} else {
ptr = mspace_calloc(heap->msp, 1, n);
if (ptr == NULL) {
return NULL;
}
}
countAllocation(heap, ptr);
/*
* Check to see if a concurrent GC should be initiated.
*/
if (gDvm.gcHeap->gcRunning || !hs->hasGcThread) {
/*
* The garbage collector thread is already running or has yet
* to be started. Do nothing.
*/
return ptr;
}
if (heap->bytesAllocated > heap->concurrentStartBytes) {
/*
* We have exceeded the allocation threshold. Wake up the
* garbage collector.
*/
dvmSignalCond(&gHs->gcThreadCond);
}
return ptr;
}
/*
* 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;
}
