| /* |
| * Copyright (C) 2008 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #include <cutils/mspace.h> |
| #include <stdint.h> |
| #include <sys/mman.h> |
| #include <errno.h> |
| |
| #define SIZE_MAX UINT_MAX // TODO: get SIZE_MAX from stdint.h |
| |
| #include "Dalvik.h" |
| #include "alloc/Heap.h" |
| #include "alloc/HeapInternal.h" |
| #include "alloc/HeapSource.h" |
| #include "alloc/HeapBitmap.h" |
| #include "alloc/HeapBitmapInlines.h" |
| |
| // TODO: find a real header file for these. |
| extern "C" int dlmalloc_trim(size_t); |
| extern "C" void dlmalloc_walk_free_pages(void(*)(void*, void*, void*), void*); |
| |
| static void snapIdealFootprint(); |
| static void setIdealFootprint(size_t max); |
| static size_t getMaximumSize(const HeapSource *hs); |
| static void trimHeaps(); |
| |
| #define HEAP_UTILIZATION_MAX 1024 |
| #define DEFAULT_HEAP_UTILIZATION 512 // Range 1..HEAP_UTILIZATION_MAX |
| #define HEAP_IDEAL_FREE (2 * 1024 * 1024) |
| #define HEAP_MIN_FREE (HEAP_IDEAL_FREE / 4) |
| |
| /* Number of seconds to wait after a GC before performing a heap trim |
| * operation to reclaim unused pages. |
| */ |
| #define HEAP_TRIM_IDLE_TIME_SECONDS 5 |
| |
| /* Start a concurrent collection when free memory falls under this |
| * many bytes. |
| */ |
| #define CONCURRENT_START (128 << 10) |
| |
| /* The next GC will not be concurrent when free memory after a GC is |
| * under this many bytes. |
| */ |
| #define CONCURRENT_MIN_FREE (CONCURRENT_START + (128 << 10)) |
| |
| #define HS_BOILERPLATE() \ |
| do { \ |
| assert(gDvm.gcHeap != NULL); \ |
| assert(gDvm.gcHeap->heapSource != NULL); \ |
| assert(gHs == gDvm.gcHeap->heapSource); \ |
| } while (0) |
| |
| struct Heap { |
| /* The mspace to allocate from. |
| */ |
| mspace msp; |
| |
| /* The largest size that this heap is allowed to grow to. |
| */ |
| size_t maximumSize; |
| |
| /* Number of bytes allocated from this mspace for objects, |
| * including any overhead. This value is NOT exact, and |
| * should only be used as an input for certain heuristics. |
| */ |
| size_t bytesAllocated; |
| |
| /* Number of bytes allocated from this mspace at which a |
| * concurrent garbage collection will be started. |
| */ |
| size_t concurrentStartBytes; |
| |
| /* Number of objects currently allocated from this mspace. |
| */ |
| size_t objectsAllocated; |
| |
| /* |
| * The lowest address of this heap, inclusive. |
| */ |
| char *base; |
| |
| /* |
| * The highest address of this heap, exclusive. |
| */ |
| char *limit; |
| }; |
| |
| struct HeapSource { |
| /* Target ideal heap utilization ratio; range 1..HEAP_UTILIZATION_MAX |
| */ |
| size_t targetUtilization; |
| |
| /* The starting heap size. |
| */ |
| size_t startSize; |
| |
| /* The largest that the heap source as a whole is allowed to grow. |
| */ |
| size_t maximumSize; |
| |
| /* |
| * The largest size we permit the heap to grow. This value allows |
| * the user to limit the heap growth below the maximum size. This |
| * is a work around until we can dynamically set the maximum size. |
| * This value can range between the starting size and the maximum |
| * size but should never be set below the current footprint of the |
| * heap. |
| */ |
| size_t growthLimit; |
| |
| /* The desired max size of the heap source as a whole. |
| */ |
| size_t idealSize; |
| |
| /* The maximum number of bytes allowed to be allocated from the |
| * active heap before a GC is forced. This is used to "shrink" the |
| * heap in lieu of actual compaction. |
| */ |
| size_t softLimit; |
| |
| /* The heaps; heaps[0] is always the active heap, |
| * which new objects should be allocated from. |
| */ |
| Heap heaps[HEAP_SOURCE_MAX_HEAP_COUNT]; |
| |
| /* The current number of heaps. |
| */ |
| size_t numHeaps; |
| |
| /* True if zygote mode was active when the HeapSource was created. |
| */ |
| bool sawZygote; |
| |
| /* |
| * The base address of the virtual memory reservation. |
| */ |
| char *heapBase; |
| |
| /* |
| * The length in bytes of the virtual memory reservation. |
| */ |
| size_t heapLength; |
| |
| /* |
| * The live object bitmap. |
| */ |
| HeapBitmap liveBits; |
| |
| /* |
| * The mark bitmap. |
| */ |
| HeapBitmap markBits; |
| |
| /* |
| * State for the GC daemon. |
| */ |
| bool hasGcThread; |
| pthread_t gcThread; |
| bool gcThreadShutdown; |
| pthread_mutex_t gcThreadMutex; |
| pthread_cond_t gcThreadCond; |
| bool gcThreadTrimNeeded; |
| }; |
| |
| #define hs2heap(hs_) (&((hs_)->heaps[0])) |
| |
| /* |
| * Returns true iff a soft limit is in effect for the active heap. |
| */ |
| static bool isSoftLimited(const HeapSource *hs) |
| { |
| /* softLimit will be either SIZE_MAX or the limit for the |
| * active mspace. idealSize can be greater than softLimit |
| * if there is more than one heap. If there is only one |
| * heap, a non-SIZE_MAX softLimit should always be the same |
| * as idealSize. |
| */ |
| return hs->softLimit <= hs->idealSize; |
| } |
| |
| /* |
| * Returns approximately the maximum number of bytes allowed to be |
| * allocated from the active heap before a GC is forced. |
| */ |
| static size_t getAllocLimit(const HeapSource *hs) |
| { |
| if (isSoftLimited(hs)) { |
| return hs->softLimit; |
| } else { |
| return mspace_max_allowed_footprint(hs2heap(hs)->msp); |
| } |
| } |
| |
| /* |
| * Returns the current footprint of all heaps. If includeActive |
| * is false, don't count the heap at index 0. |
| */ |
| static size_t oldHeapOverhead(const HeapSource *hs, bool includeActive) |
| { |
| size_t footprint = 0; |
| size_t i; |
| |
| if (includeActive) { |
| i = 0; |
| } else { |
| i = 1; |
| } |
| for (/* i = i */; i < hs->numHeaps; i++) { |
| //TODO: include size of bitmaps? If so, don't use bitsLen, listen to .max |
| footprint += mspace_footprint(hs->heaps[i].msp); |
| } |
| return footprint; |
| } |
| |
| /* |
| * Returns the heap that <ptr> could have come from, or NULL |
| * if it could not have come from any heap. |
| */ |
| static Heap *ptr2heap(const HeapSource *hs, const void *ptr) |
| { |
| const size_t numHeaps = hs->numHeaps; |
| |
| if (ptr != NULL) { |
| for (size_t i = 0; i < numHeaps; i++) { |
| const Heap *const heap = &hs->heaps[i]; |
| |
| if ((const char *)ptr >= heap->base && (const char *)ptr < heap->limit) { |
| return (Heap *)heap; |
| } |
| } |
| } |
| return NULL; |
| } |
| |
| /* |
| * Functions to update heapSource->bytesAllocated when an object |
| * is allocated or freed. mspace_usable_size() will give |
| * us a much more accurate picture of heap utilization than |
| * the requested byte sizes would. |
| * |
| * These aren't exact, and should not be treated as such. |
| */ |
| static void countAllocation(Heap *heap, const void *ptr) |
| { |
| assert(heap->bytesAllocated < mspace_footprint(heap->msp)); |
| |
| heap->bytesAllocated += mspace_usable_size(heap->msp, ptr) + |
| HEAP_SOURCE_CHUNK_OVERHEAD; |
| heap->objectsAllocated++; |
| HeapSource* hs = gDvm.gcHeap->heapSource; |
| dvmHeapBitmapSetObjectBit(&hs->liveBits, ptr); |
| |
| assert(heap->bytesAllocated < mspace_footprint(heap->msp)); |
| } |
| |
| static void countFree(Heap *heap, const void *ptr, size_t *numBytes) |
| { |
| size_t delta = mspace_usable_size(heap->msp, ptr) + HEAP_SOURCE_CHUNK_OVERHEAD; |
| assert(delta > 0); |
| if (delta < heap->bytesAllocated) { |
| heap->bytesAllocated -= delta; |
| } else { |
| heap->bytesAllocated = 0; |
| } |
| HeapSource* hs = gDvm.gcHeap->heapSource; |
| dvmHeapBitmapClearObjectBit(&hs->liveBits, ptr); |
| if (heap->objectsAllocated > 0) { |
| heap->objectsAllocated--; |
| } |
| *numBytes += delta; |
| } |
| |
| static HeapSource *gHs = NULL; |
| |
| static mspace createMspace(void *base, size_t startSize, size_t maximumSize) |
| { |
| /* Create an unlocked dlmalloc mspace to use as |
| * a heap source. |
| * |
| * We start off reserving startSize / 2 bytes but |
| * letting the heap grow to startSize. This saves |
| * memory in the case where a process uses even less |
| * than the starting size. |
| */ |
| LOGV_HEAP("Creating VM heap of size %zu", startSize); |
| errno = 0; |
| |
| mspace msp = create_contiguous_mspace_with_base(startSize/2, |
| maximumSize, /*locked=*/false, base); |
| if (msp != NULL) { |
| /* Don't let the heap grow past the starting size without |
| * our intervention. |
| */ |
| mspace_set_max_allowed_footprint(msp, startSize); |
| } else { |
| /* There's no guarantee that errno has meaning when the call |
| * fails, but it often does. |
| */ |
| LOGE_HEAP("Can't create VM heap of size (%zu,%zu): %s", |
| startSize/2, maximumSize, strerror(errno)); |
| } |
| |
| return msp; |
| } |
| |
| /* |
| * Add the initial heap. Returns false if the initial heap was |
| * already added to the heap source. |
| */ |
| static bool addInitialHeap(HeapSource *hs, mspace msp, size_t maximumSize) |
| { |
| assert(hs != NULL); |
| assert(msp != NULL); |
| if (hs->numHeaps != 0) { |
| return false; |
| } |
| hs->heaps[0].msp = msp; |
| hs->heaps[0].maximumSize = maximumSize; |
| hs->heaps[0].concurrentStartBytes = SIZE_MAX; |
| hs->heaps[0].base = hs->heapBase; |
| hs->heaps[0].limit = hs->heapBase + hs->heaps[0].maximumSize; |
| hs->numHeaps = 1; |
| return true; |
| } |
| |
| /* |
| * Adds an additional heap to the heap source. Returns false if there |
| * are too many heaps or insufficient free space to add another heap. |
| */ |
| static bool addNewHeap(HeapSource *hs) |
| { |
| Heap heap; |
| |
| assert(hs != NULL); |
| if (hs->numHeaps >= HEAP_SOURCE_MAX_HEAP_COUNT) { |
| LOGE("Attempt to create too many heaps (%zd >= %zd)", |
| hs->numHeaps, HEAP_SOURCE_MAX_HEAP_COUNT); |
| dvmAbort(); |
| return false; |
| } |
| |
| memset(&heap, 0, sizeof(heap)); |
| |
| /* |
| * Heap storage comes from a common virtual memory reservation. |
| * The new heap will start on the page after the old heap. |
| */ |
| void *sbrk0 = contiguous_mspace_sbrk0(hs->heaps[0].msp); |
| char *base = (char *)ALIGN_UP_TO_PAGE_SIZE(sbrk0); |
| size_t overhead = base - hs->heaps[0].base; |
| assert(((size_t)hs->heaps[0].base & (SYSTEM_PAGE_SIZE - 1)) == 0); |
| |
| if (overhead + HEAP_MIN_FREE >= hs->maximumSize) { |
| LOGE_HEAP("No room to create any more heaps " |
| "(%zd overhead, %zd max)", |
| overhead, hs->maximumSize); |
| return false; |
| } |
| |
| heap.maximumSize = hs->growthLimit - overhead; |
| heap.concurrentStartBytes = HEAP_MIN_FREE - CONCURRENT_START; |
| heap.base = base; |
| heap.limit = heap.base + heap.maximumSize; |
| heap.msp = createMspace(base, HEAP_MIN_FREE, hs->maximumSize - overhead); |
| if (heap.msp == NULL) { |
| return false; |
| } |
| |
| /* Don't let the soon-to-be-old heap grow any further. |
| */ |
| hs->heaps[0].maximumSize = overhead; |
| hs->heaps[0].limit = base; |
| mspace msp = hs->heaps[0].msp; |
| mspace_set_max_allowed_footprint(msp, mspace_footprint(msp)); |
| |
| /* Put the new heap in the list, at heaps[0]. |
| * Shift existing heaps down. |
| */ |
| memmove(&hs->heaps[1], &hs->heaps[0], hs->numHeaps * sizeof(hs->heaps[0])); |
| hs->heaps[0] = heap; |
| hs->numHeaps++; |
| |
| return true; |
| } |
| |
| /* |
| * The garbage collection daemon. Initiates a concurrent collection |
| * when signaled. Also periodically trims the heaps when a few seconds |
| * have elapsed since the last concurrent GC. |
| */ |
| static void *gcDaemonThread(void* arg) |
| { |
| dvmChangeStatus(NULL, THREAD_VMWAIT); |
| dvmLockMutex(&gHs->gcThreadMutex); |
| while (gHs->gcThreadShutdown != true) { |
| bool trim = false; |
| if (gHs->gcThreadTrimNeeded) { |
| int result = dvmRelativeCondWait(&gHs->gcThreadCond, &gHs->gcThreadMutex, |
| HEAP_TRIM_IDLE_TIME_SECONDS, 0); |
| if (result == ETIMEDOUT) { |
| /* Timed out waiting for a GC request, schedule a heap trim. */ |
| trim = true; |
| } |
| } else { |
| dvmWaitCond(&gHs->gcThreadCond, &gHs->gcThreadMutex); |
| } |
| |
| dvmLockHeap(); |
| /* |
| * Another thread may have started a concurrent garbage |
| * collection before we were scheduled. Check for this |
| * condition before proceeding. |
| */ |
| if (!gDvm.gcHeap->gcRunning) { |
| dvmChangeStatus(NULL, THREAD_RUNNING); |
| if (trim) { |
| trimHeaps(); |
| gHs->gcThreadTrimNeeded = false; |
| } else { |
| dvmCollectGarbageInternal(GC_CONCURRENT); |
| gHs->gcThreadTrimNeeded = true; |
| } |
| dvmChangeStatus(NULL, THREAD_VMWAIT); |
| } |
| dvmUnlockHeap(); |
| } |
| dvmChangeStatus(NULL, THREAD_RUNNING); |
| return NULL; |
| } |
| |
| static bool gcDaemonStartup() |
| { |
| dvmInitMutex(&gHs->gcThreadMutex); |
| pthread_cond_init(&gHs->gcThreadCond, NULL); |
| gHs->gcThreadShutdown = false; |
| gHs->hasGcThread = dvmCreateInternalThread(&gHs->gcThread, "GC", |
| gcDaemonThread, NULL); |
| return gHs->hasGcThread; |
| } |
| |
| static void gcDaemonShutdown() |
| { |
| if (gHs->hasGcThread) { |
| dvmLockMutex(&gHs->gcThreadMutex); |
| gHs->gcThreadShutdown = true; |
| dvmSignalCond(&gHs->gcThreadCond); |
| dvmUnlockMutex(&gHs->gcThreadMutex); |
| pthread_join(gHs->gcThread, NULL); |
| } |
| } |
| |
| /* |
| * 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. |
| */ |
| static bool allocMarkStack(GcMarkStack *stack, size_t maximumSize) |
| { |
| const char *name = "dalvik-mark-stack"; |
| void *addr; |
| |
| assert(stack != NULL); |
| stack->length = maximumSize * sizeof(Object*) / |
| (sizeof(Object) + HEAP_SOURCE_CHUNK_OVERHEAD); |
| addr = dvmAllocRegion(stack->length, PROT_READ | PROT_WRITE, name); |
| if (addr == NULL) { |
| return false; |
| } |
| stack->base = (const Object **)addr; |
| stack->limit = (const Object **)((char *)addr + stack->length); |
| stack->top = NULL; |
| madvise(stack->base, stack->length, MADV_DONTNEED); |
| return true; |
| } |
| |
| static void freeMarkStack(GcMarkStack *stack) |
| { |
| assert(stack != NULL); |
| munmap(stack->base, stack->length); |
| memset(stack, 0, sizeof(*stack)); |
| } |
| |
| /* |
| * Initializes the heap source; must be called before any other |
| * dvmHeapSource*() functions. Returns a GcHeap structure |
| * allocated from the heap source. |
| */ |
| GcHeap* dvmHeapSourceStartup(size_t startSize, size_t maximumSize, |
| size_t growthLimit) |
| { |
| GcHeap *gcHeap; |
| HeapSource *hs; |
| mspace msp; |
| size_t length; |
| void *base; |
| |
| assert(gHs == NULL); |
| |
| if (!(startSize <= growthLimit && growthLimit <= maximumSize)) { |
| LOGE("Bad heap size parameters (start=%zd, max=%zd, limit=%zd)", |
| startSize, maximumSize, growthLimit); |
| return NULL; |
| } |
| |
| /* |
| * Allocate a contiguous region of virtual memory to subdivided |
| * among the heaps managed by the garbage collector. |
| */ |
| length = ALIGN_UP_TO_PAGE_SIZE(maximumSize); |
| base = dvmAllocRegion(length, PROT_NONE, "dalvik-heap"); |
| if (base == NULL) { |
| return NULL; |
| } |
| |
| /* Create an unlocked dlmalloc mspace to use as |
| * a heap source. |
| */ |
| msp = createMspace(base, startSize, maximumSize); |
| if (msp == NULL) { |
| goto fail; |
| } |
| |
| gcHeap = (GcHeap *)malloc(sizeof(*gcHeap)); |
| if (gcHeap == NULL) { |
| LOGE_HEAP("Can't allocate heap descriptor"); |
| goto fail; |
| } |
| memset(gcHeap, 0, sizeof(*gcHeap)); |
| |
| hs = (HeapSource *)malloc(sizeof(*hs)); |
| if (hs == NULL) { |
| LOGE_HEAP("Can't allocate heap source"); |
| free(gcHeap); |
| goto fail; |
| } |
| memset(hs, 0, sizeof(*hs)); |
| |
| hs->targetUtilization = DEFAULT_HEAP_UTILIZATION; |
| hs->startSize = startSize; |
| hs->maximumSize = maximumSize; |
| hs->growthLimit = growthLimit; |
| hs->idealSize = startSize; |
| hs->softLimit = SIZE_MAX; // no soft limit at first |
| hs->numHeaps = 0; |
| hs->sawZygote = gDvm.zygote; |
| hs->hasGcThread = false; |
| hs->heapBase = (char *)base; |
| hs->heapLength = length; |
| if (!addInitialHeap(hs, msp, growthLimit)) { |
| LOGE_HEAP("Can't add initial heap"); |
| goto fail; |
| } |
| if (!dvmHeapBitmapInit(&hs->liveBits, base, length, "dalvik-bitmap-1")) { |
| LOGE_HEAP("Can't create liveBits"); |
| goto fail; |
| } |
| if (!dvmHeapBitmapInit(&hs->markBits, base, length, "dalvik-bitmap-2")) { |
| LOGE_HEAP("Can't create markBits"); |
| dvmHeapBitmapDelete(&hs->liveBits); |
| goto fail; |
| } |
| if (!allocMarkStack(&gcHeap->markContext.stack, hs->maximumSize)) { |
| LOGE("Can't create markStack"); |
| dvmHeapBitmapDelete(&hs->markBits); |
| dvmHeapBitmapDelete(&hs->liveBits); |
| goto fail; |
| } |
| gcHeap->markContext.bitmap = &hs->markBits; |
| gcHeap->heapSource = hs; |
| |
| gHs = hs; |
| return gcHeap; |
| |
| fail: |
| munmap(base, length); |
| return NULL; |
| } |
| |
| bool dvmHeapSourceStartupAfterZygote() |
| { |
| return gDvm.concurrentMarkSweep ? gcDaemonStartup() : true; |
| } |
| |
| /* |
| * This is called while in zygote mode, right before we fork() for the |
| * first time. We create a heap for all future zygote process allocations, |
| * in an attempt to avoid touching pages in the zygote heap. (This would |
| * probably be unnecessary if we had a compacting GC -- the source of our |
| * troubles is small allocations filling in the gaps from larger ones.) |
| */ |
| bool dvmHeapSourceStartupBeforeFork() |
| { |
| HeapSource *hs = gHs; // use a local to avoid the implicit "volatile" |
| |
| HS_BOILERPLATE(); |
| |
| assert(gDvm.zygote); |
| |
| if (!gDvm.newZygoteHeapAllocated) { |
| /* Create a new heap for post-fork zygote allocations. We only |
| * try once, even if it fails. |
| */ |
| LOGV("Splitting out new zygote heap"); |
| gDvm.newZygoteHeapAllocated = true; |
| return addNewHeap(hs); |
| } |
| return true; |
| } |
| |
| void dvmHeapSourceThreadShutdown() |
| { |
| if (gDvm.gcHeap != NULL && gDvm.concurrentMarkSweep) { |
| gcDaemonShutdown(); |
| } |
| } |
| |
| /* |
| * Tears down the entire GcHeap structure and all of the substructures |
| * attached to it. This call has the side effect of setting the given |
| * gcHeap pointer and gHs to NULL. |
| */ |
| void dvmHeapSourceShutdown(GcHeap **gcHeap) |
| { |
| assert(gcHeap != NULL); |
| if (*gcHeap != NULL && (*gcHeap)->heapSource != NULL) { |
| HeapSource *hs = (*gcHeap)->heapSource; |
| dvmHeapBitmapDelete(&hs->liveBits); |
| dvmHeapBitmapDelete(&hs->markBits); |
| freeMarkStack(&(*gcHeap)->markContext.stack); |
| munmap(hs->heapBase, hs->heapLength); |
| free(hs); |
| gHs = NULL; |
| free(*gcHeap); |
| *gcHeap = NULL; |
| } |
| } |
| |
| /* |
| * Gets the begining of the allocation for the HeapSource. |
| */ |
| void *dvmHeapSourceGetBase() |
| { |
| return gHs->heapBase; |
| } |
| |
| /* |
| * Returns the requested value. If the per-heap stats are requested, fill |
| * them as well. |
| * |
| * Caller must hold the heap lock. |
| */ |
| size_t dvmHeapSourceGetValue(HeapSourceValueSpec spec, size_t perHeapStats[], |
| size_t arrayLen) |
| { |
| HeapSource *hs = gHs; |
| size_t value = 0; |
| size_t total = 0; |
| |
| HS_BOILERPLATE(); |
| |
| assert(arrayLen >= hs->numHeaps || perHeapStats == NULL); |
| for (size_t i = 0; i < hs->numHeaps; i++) { |
| Heap *const heap = &hs->heaps[i]; |
| |
| switch (spec) { |
| case HS_FOOTPRINT: |
| value = mspace_footprint(heap->msp); |
| break; |
| case HS_ALLOWED_FOOTPRINT: |
| value = mspace_max_allowed_footprint(heap->msp); |
| break; |
| case HS_BYTES_ALLOCATED: |
| value = heap->bytesAllocated; |
| break; |
| case HS_OBJECTS_ALLOCATED: |
| value = heap->objectsAllocated; |
| break; |
| default: |
| // quiet gcc |
| break; |
| } |
| if (perHeapStats) { |
| perHeapStats[i] = value; |
| } |
| total += value; |
| } |
| return total; |
| } |
| |
| void dvmHeapSourceGetRegions(uintptr_t *base, uintptr_t *max, size_t numHeaps) |
| { |
| HeapSource *hs = gHs; |
| |
| HS_BOILERPLATE(); |
| |
| assert(numHeaps <= hs->numHeaps); |
| for (size_t i = 0; i < numHeaps; ++i) { |
| base[i] = (uintptr_t)hs->heaps[i].base; |
| max[i] = MIN((uintptr_t)hs->heaps[i].limit - 1, hs->markBits.max); |
| } |
| } |
| |
| /* |
| * Get the bitmap representing all live objects. |
| */ |
| HeapBitmap *dvmHeapSourceGetLiveBits() |
| { |
| HS_BOILERPLATE(); |
| |
| return &gHs->liveBits; |
| } |
| |
| /* |
| * Get the bitmap representing all marked objects. |
| */ |
| HeapBitmap *dvmHeapSourceGetMarkBits() |
| { |
| HS_BOILERPLATE(); |
| |
| return &gHs->markBits; |
| } |
| |
| void dvmHeapSourceSwapBitmaps() |
| { |
| HeapBitmap tmp = gHs->liveBits; |
| gHs->liveBits = gHs->markBits; |
| gHs->markBits = tmp; |
| } |
| |
| void dvmHeapSourceZeroMarkBitmap() |
| { |
| HS_BOILERPLATE(); |
| |
| dvmHeapBitmapZero(&gHs->markBits); |
| } |
| |
| void dvmMarkImmuneObjects(const char *immuneLimit) |
| { |
| /* |
| * Copy the contents of the live bit vector for immune object |
| * range into the mark bit vector. |
| */ |
| /* The only values generated by dvmHeapSourceGetImmuneLimit() */ |
| assert(immuneLimit == gHs->heaps[0].base || |
| immuneLimit == NULL); |
| assert(gHs->liveBits.base == gHs->markBits.base); |
| assert(gHs->liveBits.bitsLen == gHs->markBits.bitsLen); |
| /* heap[0] is never immune */ |
| assert(gHs->heaps[0].base >= immuneLimit); |
| assert(gHs->heaps[0].limit > immuneLimit); |
| |
| for (size_t i = 1; i < gHs->numHeaps; ++i) { |
| if (gHs->heaps[i].base < immuneLimit) { |
| assert(gHs->heaps[i].limit <= immuneLimit); |
| /* Compute the number of words to copy in the bitmap. */ |
| size_t index = HB_OFFSET_TO_INDEX( |
| (uintptr_t)gHs->heaps[i].base - gHs->liveBits.base); |
| /* Compute the starting offset in the live and mark bits. */ |
| char *src = (char *)(gHs->liveBits.bits + index); |
| char *dst = (char *)(gHs->markBits.bits + index); |
| /* Compute the number of bytes of the live bitmap to copy. */ |
| size_t length = HB_OFFSET_TO_BYTE_INDEX( |
| gHs->heaps[i].limit - gHs->heaps[i].base); |
| /* Do the copy. */ |
| memcpy(dst, src, length); |
| /* Make sure max points to the address of the highest set bit. */ |
| if (gHs->markBits.max < (uintptr_t)gHs->heaps[i].limit) { |
| gHs->markBits.max = (uintptr_t)gHs->heaps[i].limit; |
| } |
| } |
| } |
| } |
| |
| /* |
| * 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; |
| } |
| |
| /* Remove any hard limits, try to allocate, and shrink back down. |
| * Last resort when trying to allocate an object. |
| */ |
| static void* heapAllocAndGrow(HeapSource *hs, Heap *heap, size_t n) |
| { |
| /* Grow as much as possible, but don't let the real footprint |
| * go over the absolute max. |
| */ |
| size_t max = heap->maximumSize; |
| |
| mspace_set_max_allowed_footprint(heap->msp, max); |
| void* ptr = dvmHeapSourceAlloc(n); |
| |
| /* Shrink back down as small as possible. Our caller may |
| * readjust max_allowed to a more appropriate value. |
| */ |
| mspace_set_max_allowed_footprint(heap->msp, |
| mspace_footprint(heap->msp)); |
| return ptr; |
| } |
| |
| /* |
| * Allocates <n> bytes of zeroed data, growing as much as possible |
| * if necessary. |
| */ |
| void* dvmHeapSourceAllocAndGrow(size_t n) |
| { |
| HS_BOILERPLATE(); |
| |
| HeapSource *hs = gHs; |
| Heap* heap = hs2heap(hs); |
| void* ptr = dvmHeapSourceAlloc(n); |
| if (ptr != NULL) { |
| return ptr; |
| } |
| |
| size_t oldIdealSize = hs->idealSize; |
| if (isSoftLimited(hs)) { |
| /* We're soft-limited. Try removing the soft limit to |
| * see if we can allocate without actually growing. |
| */ |
| hs->softLimit = SIZE_MAX; |
| ptr = dvmHeapSourceAlloc(n); |
| if (ptr != NULL) { |
| /* Removing the soft limit worked; fix things up to |
| * reflect the new effective ideal size. |
| */ |
| snapIdealFootprint(); |
| return ptr; |
| } |
| // softLimit intentionally left at SIZE_MAX. |
| } |
| |
| /* We're not soft-limited. Grow the heap to satisfy the request. |
| * If this call fails, no footprints will have changed. |
| */ |
| ptr = heapAllocAndGrow(hs, heap, n); |
| if (ptr != NULL) { |
| /* The allocation succeeded. Fix up the ideal size to |
| * reflect any footprint modifications that had to happen. |
| */ |
| snapIdealFootprint(); |
| } else { |
| /* We just couldn't do it. Restore the original ideal size, |
| * fixing up softLimit if necessary. |
| */ |
| setIdealFootprint(oldIdealSize); |
| } |
| return ptr; |
| } |
| |
| /* |
| * Frees the first numPtrs objects in the ptrs list and returns the |
| * amount of reclaimed storage. The list must contain addresses all in |
| * the same mspace, and must be in increasing order. This implies that |
| * there are no duplicates, and no entries are NULL. |
| */ |
| size_t dvmHeapSourceFreeList(size_t numPtrs, void **ptrs) |
| { |
| HS_BOILERPLATE(); |
| |
| if (numPtrs == 0) { |
| return 0; |
| } |
| |
| assert(ptrs != NULL); |
| assert(*ptrs != NULL); |
| Heap* heap = ptr2heap(gHs, *ptrs); |
| size_t numBytes = 0; |
| if (heap != NULL) { |
| mspace msp = heap->msp; |
| // Calling mspace_free on shared heaps disrupts sharing too |
| // much. For heap[0] -- the 'active heap' -- we call |
| // mspace_free, but on the other heaps we only do some |
| // accounting. |
| if (heap == gHs->heaps) { |
| // mspace_merge_objects takes two allocated objects, and |
| // if the second immediately follows the first, will merge |
| // them, returning a larger object occupying the same |
| // memory. This is a local operation, and doesn't require |
| // dlmalloc to manipulate any freelists. It's pretty |
| // inexpensive compared to free(). |
| |
| // ptrs is an array of objects all in memory order, and if |
| // client code has been allocating lots of short-lived |
| // objects, this is likely to contain runs of objects all |
| // now garbage, and thus highly amenable to this optimization. |
| |
| // Unroll the 0th iteration around the loop below, |
| // countFree ptrs[0] and initializing merged. |
| assert(ptrs[0] != NULL); |
| assert(ptr2heap(gHs, ptrs[0]) == heap); |
| countFree(heap, ptrs[0], &numBytes); |
| void *merged = ptrs[0]; |
| for (size_t i = 1; i < numPtrs; i++) { |
| assert(merged != NULL); |
| assert(ptrs[i] != NULL); |
| assert((intptr_t)merged < (intptr_t)ptrs[i]); |
| assert(ptr2heap(gHs, ptrs[i]) == heap); |
| countFree(heap, ptrs[i], &numBytes); |
| // Try to merge. If it works, merged now includes the |
| // memory of ptrs[i]. If it doesn't, free merged, and |
| // see if ptrs[i] starts a new run of adjacent |
| // objects to merge. |
| if (mspace_merge_objects(msp, merged, ptrs[i]) == NULL) { |
| mspace_free(msp, merged); |
| merged = ptrs[i]; |
| } |
| } |
| assert(merged != NULL); |
| mspace_free(msp, merged); |
| } else { |
| // This is not an 'active heap'. Only do the accounting. |
| for (size_t i = 0; i < numPtrs; i++) { |
| assert(ptrs[i] != NULL); |
| assert(ptr2heap(gHs, ptrs[i]) == heap); |
| countFree(heap, ptrs[i], &numBytes); |
| } |
| } |
| } |
| return numBytes; |
| } |
| |
| /* |
| * Returns true iff <ptr> is in the heap source. |
| */ |
| bool dvmHeapSourceContainsAddress(const void *ptr) |
| { |
| HS_BOILERPLATE(); |
| |
| return (dvmHeapBitmapCoversAddress(&gHs->liveBits, ptr)); |
| } |
| |
| /* |
| * Returns true iff <ptr> was allocated from the heap source. |
| */ |
| bool dvmHeapSourceContains(const void *ptr) |
| { |
| HS_BOILERPLATE(); |
| |
| if (dvmHeapSourceContainsAddress(ptr)) { |
| return dvmHeapBitmapIsObjectBitSet(&gHs->liveBits, ptr) != 0; |
| } |
| return false; |
| } |
| |
| bool dvmIsZygoteObject(const Object* obj) |
| { |
| HeapSource *hs = gHs; |
| |
| HS_BOILERPLATE(); |
| |
| if (dvmHeapSourceContains(obj) && hs->sawZygote) { |
| Heap *heap = ptr2heap(hs, obj); |
| if (heap != NULL) { |
| /* If the object is not in the active heap, we assume that |
| * it was allocated as part of zygote. |
| */ |
| return heap != hs->heaps; |
| } |
| } |
| /* The pointer is outside of any known heap, or we are not |
| * running in zygote mode. |
| */ |
| return false; |
| } |
| |
| /* |
| * Returns the number of usable bytes in an allocated chunk; the size |
| * may be larger than the size passed to dvmHeapSourceAlloc(). |
| */ |
| size_t dvmHeapSourceChunkSize(const void *ptr) |
| { |
| HS_BOILERPLATE(); |
| |
| Heap* heap = ptr2heap(gHs, ptr); |
| if (heap != NULL) { |
| return mspace_usable_size(heap->msp, ptr); |
| } |
| return 0; |
| } |
| |
| /* |
| * Returns the number of bytes that the heap source has allocated |
| * from the system using sbrk/mmap, etc. |
| * |
| * Caller must hold the heap lock. |
| */ |
| size_t dvmHeapSourceFootprint() |
| { |
| HS_BOILERPLATE(); |
| |
| //TODO: include size of bitmaps? |
| return oldHeapOverhead(gHs, true); |
| } |
| |
| static size_t getMaximumSize(const HeapSource *hs) |
| { |
| return hs->growthLimit; |
| } |
| |
| /* |
| * Returns the current maximum size of the heap source respecting any |
| * growth limits. |
| */ |
| size_t dvmHeapSourceGetMaximumSize() |
| { |
| HS_BOILERPLATE(); |
| return getMaximumSize(gHs); |
| } |
| |
| /* |
| * 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(); |
| } |
| |
| /* |
| * Return the real bytes used by old heaps plus the soft usage of the |
| * current heap. When a soft limit is in effect, this is effectively |
| * what it's compared against (though, in practice, it only looks at |
| * the current heap). |
| */ |
| static size_t getSoftFootprint(bool includeActive) |
| { |
| HS_BOILERPLATE(); |
| |
| HeapSource *hs = gHs; |
| size_t ret = oldHeapOverhead(hs, false); |
| if (includeActive) { |
| ret += hs->heaps[0].bytesAllocated; |
| } |
| |
| return ret; |
| } |
| |
| /* |
| * Gets the maximum number of bytes that the heap source is allowed |
| * to allocate from the system. |
| */ |
| size_t dvmHeapSourceGetIdealFootprint() |
| { |
| HeapSource *hs = gHs; |
| |
| HS_BOILERPLATE(); |
| |
| return hs->idealSize; |
| } |
| |
| /* |
| * Sets the soft limit, handling any necessary changes to the allowed |
| * footprint of the active heap. |
| */ |
| static void setSoftLimit(HeapSource *hs, size_t softLimit) |
| { |
| /* Compare against the actual footprint, rather than the |
| * max_allowed, because the heap may not have grown all the |
| * way to the allowed size yet. |
| */ |
| mspace msp = hs->heaps[0].msp; |
| size_t currentHeapSize = mspace_footprint(msp); |
| if (softLimit < currentHeapSize) { |
| /* Don't let the heap grow any more, and impose a soft limit. |
| */ |
| mspace_set_max_allowed_footprint(msp, currentHeapSize); |
| hs->softLimit = softLimit; |
| } else { |
| /* Let the heap grow to the requested max, and remove any |
| * soft limit, if set. |
| */ |
| mspace_set_max_allowed_footprint(msp, softLimit); |
| hs->softLimit = SIZE_MAX; |
| } |
| } |
| |
| /* |
| * Sets the maximum number of bytes that the heap source is allowed |
| * to allocate from the system. Clamps to the appropriate maximum |
| * value. |
| */ |
| static void setIdealFootprint(size_t max) |
| { |
| HS_BOILERPLATE(); |
| |
| HeapSource *hs = gHs; |
| size_t maximumSize = getMaximumSize(hs); |
| if (max > maximumSize) { |
| LOGI_HEAP("Clamp target GC heap from %zd.%03zdMB to %u.%03uMB", |
| FRACTIONAL_MB(max), |
| FRACTIONAL_MB(maximumSize)); |
| max = maximumSize; |
| } |
| |
| /* Convert max into a size that applies to the active heap. |
| * Old heaps will count against the ideal size. |
| */ |
| size_t overhead = getSoftFootprint(false); |
| size_t activeMax; |
| if (overhead < max) { |
| activeMax = max - overhead; |
| } else { |
| activeMax = 0; |
| } |
| |
| setSoftLimit(hs, activeMax); |
| hs->idealSize = max; |
| } |
| |
| /* |
| * Make the ideal footprint equal to the current footprint. |
| */ |
| static void snapIdealFootprint() |
| { |
| HS_BOILERPLATE(); |
| |
| setIdealFootprint(getSoftFootprint(true)); |
| } |
| |
| /* |
| * Gets the current ideal heap utilization, represented as a number |
| * between zero and one. |
| */ |
| float dvmGetTargetHeapUtilization() |
| { |
| HeapSource *hs = gHs; |
| |
| HS_BOILERPLATE(); |
| |
| return (float)hs->targetUtilization / (float)HEAP_UTILIZATION_MAX; |
| } |
| |
| /* |
| * Sets the new ideal heap utilization, represented as a number |
| * between zero and one. |
| */ |
| void dvmSetTargetHeapUtilization(float newTarget) |
| { |
| HeapSource *hs = gHs; |
| |
| HS_BOILERPLATE(); |
| |
| /* Clamp it to a reasonable range. |
| */ |
| // TODO: This may need some tuning. |
| if (newTarget < 0.2) { |
| newTarget = 0.2; |
| } else if (newTarget > 0.8) { |
| newTarget = 0.8; |
| } |
| |
| hs->targetUtilization = |
| (size_t)(newTarget * (float)HEAP_UTILIZATION_MAX); |
| LOGV("Set heap target utilization to %zd/%d (%f)", |
| hs->targetUtilization, HEAP_UTILIZATION_MAX, newTarget); |
| } |
| |
| /* |
| * Given the size of a live set, returns the ideal heap size given |
| * the current target utilization and MIN/MAX values. |
| * |
| * targetUtilization is in the range 1..HEAP_UTILIZATION_MAX. |
| */ |
| static size_t getUtilizationTarget(size_t liveSize, size_t targetUtilization) |
| { |
| /* Use the current target utilization ratio to determine the |
| * ideal heap size based on the size of the live set. |
| */ |
| size_t targetSize = (liveSize / targetUtilization) * HEAP_UTILIZATION_MAX; |
| |
| /* Cap the amount of free space, though, so we don't end up |
| * with, e.g., 8MB of free space when the live set size hits 8MB. |
| */ |
| if (targetSize > liveSize + HEAP_IDEAL_FREE) { |
| targetSize = liveSize + HEAP_IDEAL_FREE; |
| } else if (targetSize < liveSize + HEAP_MIN_FREE) { |
| targetSize = liveSize + HEAP_MIN_FREE; |
| } |
| return targetSize; |
| } |
| |
| /* |
| * Given the current contents of the active heap, increase the allowed |
| * heap footprint to match the target utilization ratio. This |
| * should only be called immediately after a full mark/sweep. |
| */ |
| void dvmHeapSourceGrowForUtilization() |
| { |
| HS_BOILERPLATE(); |
| |
| HeapSource *hs = gHs; |
| Heap* heap = hs2heap(hs); |
| |
| /* Use the current target utilization ratio to determine the |
| * ideal heap size based on the size of the live set. |
| * Note that only the active heap plays any part in this. |
| * |
| * Avoid letting the old heaps influence the target free size, |
| * because they may be full of objects that aren't actually |
| * in the working set. Just look at the allocated size of |
| * the current heap. |
| */ |
| size_t currentHeapUsed = heap->bytesAllocated; |
| size_t targetHeapSize = |
| getUtilizationTarget(currentHeapUsed, hs->targetUtilization); |
| |
| /* The ideal size includes the old heaps; add overhead so that |
| * it can be immediately subtracted again in setIdealFootprint(). |
| * If the target heap size would exceed the max, setIdealFootprint() |
| * will clamp it to a legal value. |
| */ |
| size_t overhead = getSoftFootprint(false); |
| setIdealFootprint(targetHeapSize + overhead); |
| |
| size_t freeBytes = getAllocLimit(hs); |
| if (freeBytes < CONCURRENT_MIN_FREE) { |
| /* Not enough free memory to allow a concurrent GC. */ |
| heap->concurrentStartBytes = SIZE_MAX; |
| } else { |
| heap->concurrentStartBytes = freeBytes - CONCURRENT_START; |
| } |
| } |
| |
| /* |
| * Return free pages to the system. |
| * TODO: move this somewhere else, especially the native heap part. |
| */ |
| static void releasePagesInRange(void *start, void *end, void *nbytes) |
| { |
| /* Linux requires that the madvise() start address is page-aligned. |
| * We also align the end address. |
| */ |
| start = (void *)ALIGN_UP_TO_PAGE_SIZE(start); |
| end = (void *)((size_t)end & ~(SYSTEM_PAGE_SIZE - 1)); |
| if (start < end) { |
| size_t length = (char *)end - (char *)start; |
| madvise(start, length, MADV_DONTNEED); |
| *(size_t *)nbytes += length; |
| } |
| } |
| |
| /* |
| * Return unused memory to the system if possible. |
| */ |
| static void trimHeaps() |
| { |
| HS_BOILERPLATE(); |
| |
| HeapSource *hs = gHs; |
| size_t heapBytes = 0; |
| for (size_t i = 0; i < hs->numHeaps; i++) { |
| Heap *heap = &hs->heaps[i]; |
| |
| /* Return the wilderness chunk to the system. |
| */ |
| mspace_trim(heap->msp, 0); |
| |
| /* Return any whole free pages to the system. |
| */ |
| mspace_walk_free_pages(heap->msp, releasePagesInRange, &heapBytes); |
| } |
| |
| /* Same for the native heap. |
| */ |
| dlmalloc_trim(0); |
| size_t nativeBytes = 0; |
| dlmalloc_walk_free_pages(releasePagesInRange, &nativeBytes); |
| |
| LOGD_HEAP("madvised %zd (GC) + %zd (native) = %zd total bytes", |
| heapBytes, nativeBytes, heapBytes + nativeBytes); |
| } |
| |
| /* |
| * Walks over the heap source and passes every allocated and |
| * free chunk to the callback. |
| */ |
| void dvmHeapSourceWalk(void(*callback)(const void *chunkptr, size_t chunklen, |
| const void *userptr, size_t userlen, |
| void *arg), |
| void *arg) |
| { |
| HS_BOILERPLATE(); |
| |
| /* Walk the heaps from oldest to newest. |
| */ |
| //TODO: do this in address order |
| HeapSource *hs = gHs; |
| for (size_t i = hs->numHeaps; i > 0; --i) { |
| mspace_walk_heap(hs->heaps[i-1].msp, callback, arg); |
| } |
| } |
| |
| /* |
| * Gets the number of heaps available in the heap source. |
| * |
| * Caller must hold the heap lock, because gHs caches a field |
| * in gDvm.gcHeap. |
| */ |
| size_t dvmHeapSourceGetNumHeaps() |
| { |
| HS_BOILERPLATE(); |
| |
| return gHs->numHeaps; |
| } |
| |
| void *dvmHeapSourceGetImmuneLimit(bool isPartial) |
| { |
| if (isPartial) { |
| return hs2heap(gHs)->base; |
| } else { |
| return NULL; |
| } |
| } |