static bool
createMarkStack(GcMarkStack *stack)
{
const Object **limit;
size_t size;
int fd;
/* Create a stack big enough for the worst possible case,
* where the heap is perfectly full of the smallest object.
* TODO: be better about memory usage; use a smaller stack with
* overflow detection and recovery.
*/
size = dvmHeapSourceGetIdealFootprint() /
(sizeof(Object) + HEAP_SOURCE_CHUNK_OVERHEAD);
size = ALIGN_UP_TO_PAGE_SIZE(size);
fd = ashmem_create_region("dalvik-heap-markstack", size);
if (fd < 0) {
LOGE_GC("Could not create %d-byte ashmem mark stack\n", size);
return false;
}
limit = (const Object **)mmap(NULL, size, PROT_READ | PROT_WRITE,
MAP_PRIVATE, fd, 0);
close(fd);
if (limit == MAP_FAILED) {
LOGE_GC("Could not mmap %d-byte ashmem mark stack\n", size);
return false;
}
memset(stack, 0, sizeof(*stack));
stack->limit = limit;
stack->base = (const Object **)((uintptr_t)limit + size);
stack->top = stack->base;
return true;
}
static bool createMarkStack(GcMarkStack *stack)
{
const Object **limit;
const char *name;
size_t size;
/* Create a stack big enough for the worst possible case,
* where the heap is perfectly full of the smallest object.
* TODO: be better about memory usage; use a smaller stack with
* overflow detection and recovery.
*/
size = dvmHeapSourceGetIdealFootprint() * sizeof(Object*) /
(sizeof(Object) + HEAP_SOURCE_CHUNK_OVERHEAD);
size = ALIGN_UP_TO_PAGE_SIZE(size);
name = "dalvik-mark-stack";
limit = dvmAllocRegion(size, PROT_READ | PROT_WRITE, name);
if (limit == NULL) {
LOGE_GC("Could not mmap %zd-byte ashmem region '%s'", size, name);
return false;
}
stack->limit = limit;
stack->base = (const Object **)((uintptr_t)limit + size);
stack->top = stack->base;
return true;
}
/*
* Initializes the stack top and advises the mark stack pages as needed.
*/
static bool createMarkStack(GcMarkStack *stack)
{
assert(stack != NULL);
size_t length = dvmHeapSourceGetIdealFootprint() * sizeof(Object*) /
(sizeof(Object) + HEAP_SOURCE_CHUNK_OVERHEAD);
madvise(stack->base, length, MADV_NORMAL);
stack->top = stack->base;
return true;
}
/* 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;
}
void dvmLogGcStats(size_t numFreed, size_t sizeFreed, size_t gcTimeMs)
{
size_t perHeapActualSize[HEAP_SOURCE_MAX_HEAP_COUNT],
perHeapAllowedSize[HEAP_SOURCE_MAX_HEAP_COUNT],
perHeapNumAllocated[HEAP_SOURCE_MAX_HEAP_COUNT],
perHeapSizeAllocated[HEAP_SOURCE_MAX_HEAP_COUNT];
unsigned char eventBuf[1 + (1 + sizeof(long long)) * 4];
size_t actualSize, allowedSize, numAllocated, sizeAllocated;
size_t softLimit = dvmHeapSourceGetIdealFootprint();
size_t nHeaps = dvmHeapSourceGetNumHeaps();
/* Enough to quiet down gcc for unitialized variable check */
perHeapActualSize[0] = perHeapAllowedSize[0] = perHeapNumAllocated[0] =
perHeapSizeAllocated[0] = 0;
actualSize = dvmHeapSourceGetValue(HS_FOOTPRINT, perHeapActualSize,
HEAP_SOURCE_MAX_HEAP_COUNT);
allowedSize = dvmHeapSourceGetValue(HS_ALLOWED_FOOTPRINT,
perHeapAllowedSize, HEAP_SOURCE_MAX_HEAP_COUNT);
numAllocated = dvmHeapSourceGetValue(HS_OBJECTS_ALLOCATED,
perHeapNumAllocated, HEAP_SOURCE_MAX_HEAP_COUNT);
sizeAllocated = dvmHeapSourceGetValue(HS_BYTES_ALLOCATED,
perHeapSizeAllocated, HEAP_SOURCE_MAX_HEAP_COUNT);
/*
* Construct the the first 64-bit value to write to the log.
* Global information:
*
* [63 ] Must be zero
* [62-24] ASCII process identifier
* [23-12] GC time in ms
* [11- 0] Bytes freed
*
*/
long long event0;
event0 = 0LL << 63 |
(long long)intToFloat12(gcTimeMs) << 12 |
(long long)intToFloat12(sizeFreed);
insertProcessName(&event0);
/*
* Aggregated heap stats:
*
* [63-62] 10
* [61-60] Reserved; must be zero
* [59-48] Objects freed
* [47-36] Actual size (current footprint)
* [35-24] Allowed size (current hard max)
* [23-12] Objects allocated
* [11- 0] Bytes allocated
*/
long long event1;
event1 = 2LL << 62 |
(long long)intToFloat12(numFreed) << 48 |
(long long)intToFloat12(actualSize) << 36 |
(long long)intToFloat12(allowedSize) << 24 |
(long long)intToFloat12(numAllocated) << 12 |
(long long)intToFloat12(sizeAllocated);
/*
* Report the current state of the zygote heap(s).
*
* The active heap is always heap[0]. We can be in one of three states
* at present:
*
* (1) Still in the zygote. Zygote using heap[0].
* (2) In the zygote, when the first child is started. We created a
* new heap just before the first fork() call, so the original
* "zygote heap" is now heap[1], and we have a small heap[0] for
* anything we do from here on.
* (3) In an app process. The app gets a new heap[0], and can also
* see the two zygote heaps [1] and [2] (probably unwise to
* assume any specific ordering).
*
* So if nHeaps == 1, we want the stats from heap[0]; else we want
* the sum of the values from heap[1] to heap[nHeaps-1].
*
*
* Zygote heap stats (except for the soft limit, which belongs to the
* active heap):
*
* [63-62] 11
* [61-60] Reserved; must be zero
* [59-48] Soft Limit (for the active heap)
* [47-36] Actual size (current footprint)
* [35-24] Allowed size (current hard max)
* [23-12] Objects allocated
* [11- 0] Bytes allocated
*/
long long event2;
size_t zActualSize, zAllowedSize, zNumAllocated, zSizeAllocated;
int firstHeap = (nHeaps == 1) ? 0 : 1;
size_t hh;
zActualSize = zAllowedSize = zNumAllocated = zSizeAllocated = 0;
for (hh = firstHeap; hh < nHeaps; hh++) {
zActualSize += perHeapActualSize[hh];
zAllowedSize += perHeapAllowedSize[hh];
zNumAllocated += perHeapNumAllocated[hh];
zSizeAllocated += perHeapSizeAllocated[hh];
}
event2 = 3LL << 62 |
(long long)intToFloat12(softLimit) << 48 |
(long long)intToFloat12(zActualSize) << 36 |
(long long)intToFloat12(zAllowedSize) << 24 |
(long long)intToFloat12(zNumAllocated) << 12 |
(long long)intToFloat12(zSizeAllocated);
/*
* Report the current external allocation stats and the native heap
* summary.
*
* [63-48] Reserved; must be zero (TODO: put new data in these slots)
* [47-36] dlmalloc_footprint
* [35-24] mallinfo: total allocated space
* [23-12] External byte limit
* [11- 0] External bytes allocated
*/
long long event3;
size_t externalLimit, externalBytesAllocated;
size_t uordblks, footprint;
#if 0
/*
* This adds 2-5msec to the GC cost on a DVT, or about 2-3% of the cost
* of a GC, so it's not horribly expensive but it's not free either.
*/
extern size_t dlmalloc_footprint(void);
struct mallinfo mi;
//u8 start, end;
//start = dvmGetRelativeTimeNsec();
mi = mallinfo();
uordblks = mi.uordblks;
footprint = dlmalloc_footprint();
//end = dvmGetRelativeTimeNsec();
//LOGD("mallinfo+footprint took %dusec; used=%zd footprint=%zd\n",
// (int)((end - start) / 1000), mi.uordblks, footprint);
#else
uordblks = footprint = 0;
#endif
externalLimit =
dvmHeapSourceGetValue(HS_EXTERNAL_LIMIT, NULL, 0);
externalBytesAllocated =
dvmHeapSourceGetValue(HS_EXTERNAL_BYTES_ALLOCATED, NULL, 0);
event3 =
(long long)intToFloat12(footprint) << 36 |
(long long)intToFloat12(uordblks) << 24 |
(long long)intToFloat12(externalLimit) << 12 |
(long long)intToFloat12(externalBytesAllocated);
/* Build the event data.
* [ 0: 0] item count (4)
* [ 1: 1] EVENT_TYPE_LONG
* [ 2: 9] event0
* [10:10] EVENT_TYPE_LONG
* [11:18] event1
* [19:19] EVENT_TYPE_LONG
* [20:27] event2
* [28:28] EVENT_TYPE_LONG
* [29:36] event2
*/
unsigned char *c = eventBuf;
*c++ = 4;
*c++ = EVENT_TYPE_LONG;
memcpy(c, &event0, sizeof(event0));
c += sizeof(event0);
*c++ = EVENT_TYPE_LONG;
memcpy(c, &event1, sizeof(event1));
c += sizeof(event1);
*c++ = EVENT_TYPE_LONG;
memcpy(c, &event2, sizeof(event2));
c += sizeof(event2);
*c++ = EVENT_TYPE_LONG;
memcpy(c, &event3, sizeof(event3));
(void) android_btWriteLog(EVENT_LOG_TAG_dvm_gc_info, EVENT_TYPE_LIST,
eventBuf, sizeof(eventBuf));
}
