diff --git a/include/utils/LinearAllocator.h b/include/utils/LinearAllocator.h new file mode 100644 index 000000000..4772bc8f7 --- /dev/null +++ b/include/utils/LinearAllocator.h @@ -0,0 +1,97 @@ +/* + * Copyright 2012, The Android Open Source Project + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * * Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ``AS IS'' AND ANY + * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR + * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR + * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, + * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, + * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR + * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY + * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#ifndef ANDROID_LINEARALLOCATOR_H +#define ANDROID_LINEARALLOCATOR_H + +#include + +namespace android { + +/** + * A memory manager that internally allocates multi-kbyte buffers for placing objects in. It avoids + * the overhead of malloc when many objects are allocated. It is most useful when creating many + * small objects with a similar lifetime, and doesn't add significant overhead for large + * allocations. + */ +class LinearAllocator { +public: + LinearAllocator(); + ~LinearAllocator(); + + /** + * Reserves and returns a region of memory of at least size 'size', aligning as needed. + * Typically this is used in an object's overridden new() method or as a replacement for malloc. + * + * The lifetime of the returned buffers is tied to that of the LinearAllocator. If calling + * delete() on an object stored in a buffer is needed, it should be overridden to use + * rewindIfLastAlloc() + */ + void* alloc(size_t size); + + /** + * Attempt to deallocate the given buffer, with the LinearAllocator attempting to rewind its + * state if possible. No destructors are called. + */ + void rewindIfLastAlloc(void* ptr, size_t allocSize); + + /** + * Dump memory usage statistics to the log (allocated and wasted space) + */ + void dumpMemoryStats(const char* prefix = ""); + + /** + * The number of bytes used for buffers allocated in the LinearAllocator (does not count space + * wasted) + */ + size_t usedSize() const { return mTotalAllocated - mWastedSpace; } + +private: + LinearAllocator(const LinearAllocator& other); + + class Page; + + Page* newPage(size_t pageSize); + bool fitsInCurrentPage(size_t size); + void ensureNext(size_t size); + void* start(Page *p); + void* end(Page* p); + + size_t mPageSize; + size_t mMaxAllocSize; + void* mNext; + Page* mCurrentPage; + Page* mPages; + + // Memory usage tracking + size_t mTotalAllocated; + size_t mWastedSpace; + size_t mPageCount; + size_t mDedicatedPageCount; +}; + +}; // namespace android + +#endif // ANDROID_LINEARALLOCATOR_H diff --git a/libs/utils/Android.mk b/libs/utils/Android.mk index 73a98d5f8..cbfe7bdce 100644 --- a/libs/utils/Android.mk +++ b/libs/utils/Android.mk @@ -26,6 +26,7 @@ commonSources:= \ FileMap.cpp \ Flattenable.cpp \ JenkinsHash.cpp \ + LinearAllocator.cpp \ LinearTransform.cpp \ Log.cpp \ PropertyMap.cpp \ @@ -112,6 +113,10 @@ ifeq ($(TARGET_OS),linux) LOCAL_LDLIBS += -lrt -ldl endif +ifeq ($(TARGET_ARCH),mips) +LOCAL_CFLAGS += -DALIGN_DOUBLE +endif + LOCAL_C_INCLUDES += \ bionic/libc/private \ external/zlib diff --git a/libs/utils/LinearAllocator.cpp b/libs/utils/LinearAllocator.cpp new file mode 100644 index 000000000..a07a2916e --- /dev/null +++ b/libs/utils/LinearAllocator.cpp @@ -0,0 +1,227 @@ +/* + * Copyright 2012, The Android Open Source Project + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * * Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ``AS IS'' AND ANY + * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR + * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR + * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, + * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, + * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR + * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY + * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#define LOG_TAG "LinearAllocator" +#define LOG_NDEBUG 1 + +#include +#include +#include + + +// The ideal size of a page allocation (these need to be multiples of 8) +#define INITIAL_PAGE_SIZE ((size_t)4096) // 4kb +#define MAX_PAGE_SIZE ((size_t)131072) // 128kb + +// The maximum amount of wasted space we can have per page +// Allocations exceeding this will have their own dedicated page +// If this is too low, we will malloc too much +// Too high, and we may waste too much space +// Must be smaller than INITIAL_PAGE_SIZE +#define MAX_WASTE_SIZE ((size_t)1024) + +#if ALIGN_DOUBLE +#define ALIGN_SZ (sizeof(double)) +#else +#define ALIGN_SZ (sizeof(int)) +#endif + +#define ALIGN(x) ((x + ALIGN_SZ - 1 ) & ~(ALIGN_SZ - 1)) +#define ALIGN_PTR(p) ((void*)(ALIGN((size_t)p))) + +#if LOG_NDEBUG +#define ADD_ALLOCATION(size) +#define RM_ALLOCATION(size) +#else +#include +#include +static size_t s_totalAllocations = 0; +static nsecs_t s_nextLog = 0; +static android::Mutex s_mutex; + +static void _logUsageLocked() { + nsecs_t now = systemTime(SYSTEM_TIME_MONOTONIC); + if (now > s_nextLog) { + s_nextLog = now + milliseconds_to_nanoseconds(10); + ALOGV("Total memory usage: %zu kb", s_totalAllocations / 1024); + } +} + +static void _addAllocation(size_t size) { + android::AutoMutex lock(s_mutex); + s_totalAllocations += size; + _logUsageLocked(); +} + +#define ADD_ALLOCATION(size) _addAllocation(size); +#define RM_ALLOCATION(size) _addAllocation(-size); +#endif + +#define min(x,y) (((x) < (y)) ? (x) : (y)) + +namespace android { + +class LinearAllocator::Page { +public: + Page* next() { return mNextPage; } + void setNext(Page* next) { mNextPage = next; } + + Page() + : mNextPage(0) + {} + + void* operator new(size_t size, void* buf) { return buf; } + + void* start() { + return (void*) (((size_t)this) + sizeof(Page)); + } + + void* end(int pageSize) { + return (void*) (((size_t)start()) + pageSize); + } + +private: + Page(const Page& other) {} + Page* mNextPage; +}; + +LinearAllocator::LinearAllocator() + : mPageSize(INITIAL_PAGE_SIZE) + , mMaxAllocSize(MAX_WASTE_SIZE) + , mNext(0) + , mCurrentPage(0) + , mPages(0) + , mTotalAllocated(0) + , mWastedSpace(0) + , mPageCount(0) + , mDedicatedPageCount(0) {} + +LinearAllocator::~LinearAllocator(void) { + Page* p = mPages; + while (p) { + Page* next = p->next(); + p->~Page(); + free(p); + RM_ALLOCATION(mPageSize); + p = next; + } +} + +void* LinearAllocator::start(Page* p) { + return ALIGN_PTR(((size_t*)p) + sizeof(Page)); +} + +void* LinearAllocator::end(Page* p) { + return ((char*)p) + mPageSize; +} + +bool LinearAllocator::fitsInCurrentPage(size_t size) { + return mNext && ((char*)mNext + size) <= end(mCurrentPage); +} + +void LinearAllocator::ensureNext(size_t size) { + if (fitsInCurrentPage(size)) return; + + if (mCurrentPage && mPageSize < MAX_PAGE_SIZE) { + mPageSize = min(MAX_PAGE_SIZE, mPageSize * 2); + mPageSize = ALIGN(mPageSize); + } + mWastedSpace += mPageSize; + Page* p = newPage(mPageSize); + if (mCurrentPage) { + mCurrentPage->setNext(p); + } + mCurrentPage = p; + if (!mPages) { + mPages = mCurrentPage; + } + mNext = start(mCurrentPage); +} + +void* LinearAllocator::alloc(size_t size) { + size = ALIGN(size); + if (size > mMaxAllocSize && !fitsInCurrentPage(size)) { + ALOGV("Exceeded max size %zu > %zu", size, mMaxAllocSize); + // Allocation is too large, create a dedicated page for the allocation + Page* page = newPage(size); + mDedicatedPageCount++; + page->setNext(mPages); + mPages = page; + if (!mCurrentPage) + mCurrentPage = mPages; + return start(page); + } + ensureNext(size); + void* ptr = mNext; + mNext = ((char*)mNext) + size; + mWastedSpace -= size; + return ptr; +} + +void LinearAllocator::rewindIfLastAlloc(void* ptr, size_t allocSize) { + // Don't bother rewinding across pages + allocSize = ALIGN(allocSize); + if (ptr >= start(mCurrentPage) && ptr < end(mCurrentPage) + && ptr == ((char*)mNext - allocSize)) { + mTotalAllocated -= allocSize; + mWastedSpace += allocSize; + mNext = ptr; + } +} + +LinearAllocator::Page* LinearAllocator::newPage(size_t pageSize) { + pageSize = ALIGN(pageSize + sizeof(LinearAllocator::Page)); + ADD_ALLOCATION(pageSize); + mTotalAllocated += pageSize; + mPageCount++; + void* buf = malloc(pageSize); + return new (buf) Page(); +} + +static const char* toSize(size_t value, float& result) { + if (value < 2000) { + result = value; + return "B"; + } + if (value < 2000000) { + result = value / 1024.0f; + return "KB"; + } + result = value / 1048576.0f; + return "MB"; +} + +void LinearAllocator::dumpMemoryStats(const char* prefix) { + float prettySize; + const char* prettySuffix; + prettySuffix = toSize(mTotalAllocated, prettySize); + ALOGD("%sTotal allocated: %.2f%s", prefix, prettySize, prettySuffix); + prettySuffix = toSize(mWastedSpace, prettySize); + ALOGD("%sWasted space: %.2f%s (%.1f%%)", prefix, prettySize, prettySuffix, + (float) mWastedSpace / (float) mTotalAllocated * 100.0f); + ALOGD("%sPages %zu (dedicated %zu)", prefix, mPageCount, mDedicatedPageCount); +} + +}; // namespace android