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/*
* 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 <stdlib.h>
#include <utils/LinearAllocator.h>
#include <utils/Log.h>
// 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 <utils/Thread.h>
#include <utils/Timers.h>
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
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