/*
* 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;
}
/*
* 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;
}