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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 "config.h"
#include "LinearAllocator.h"
#include "AndroidLog.h"
namespace WebCore {
// The ideal size of a page allocation (these need to be multiples of 4)
#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)
#define ALIGN(x) (x + (x % sizeof(int)))
#if LOG_NDEBUG
#define ADD_ALLOCATION(size)
#define RM_ALLOCATION(size)
#else
#include <utils/Thread.h>
static size_t s_totalAllocations = 0;
static double s_lastLogged = 0;
static android::Mutex s_mutex;
static void _logUsageLocked() {
double now = currentTimeMS();
if (now - s_lastLogged > 5) {
s_lastLogged = now;
ALOGV("Total memory usage: %d 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
class LinearAllocator::Page {
public:
Page* next() { return m_nextPage; }
void setNext(Page* next) { m_nextPage = next; }
Page()
: m_nextPage(0)
{}
void* start()
{
return (void*) (((unsigned)this) + sizeof(LinearAllocator::Page));
}
void* end(int pageSize)
{
return (void*) (((unsigned)start()) + pageSize);
}
private:
Page(const Page& other) {}
Page* m_nextPage;
};
LinearAllocator::LinearAllocator()
: m_pageSize(INITIAL_PAGE_SIZE)
, m_maxAllocSize(MAX_WASTE_SIZE)
, m_next(0)
, m_currentPage(0)
, m_pages(0)
, m_totalAllocated(0)
, m_wastedSpace(0)
, m_pageCount(0)
, m_dedicatedPageCount(0)
{
}
LinearAllocator::~LinearAllocator(void)
{
Page* p = m_pages;
while (p) {
Page* next = p->next();
delete p;
RM_ALLOCATION(m_pageSize);
p = next;
}
}
void* LinearAllocator::start(Page* p)
{
return ((char*)p) + sizeof(Page);
}
void* LinearAllocator::end(Page* p)
{
return ((char*)p) + m_pageSize;
}
bool LinearAllocator::fitsInCurrentPage(size_t size)
{
return m_next && ((char*)m_next + size) <= end(m_currentPage);
}
void LinearAllocator::ensureNext(size_t size)
{
if (fitsInCurrentPage(size))
return;
if (m_currentPage && m_pageSize < MAX_PAGE_SIZE) {
m_pageSize = std::min(MAX_PAGE_SIZE, m_pageSize * 2);
m_pageSize = ALIGN(m_pageSize);
}
m_wastedSpace += m_pageSize;
Page* p = newPage(m_pageSize);
if (m_currentPage)
m_currentPage->setNext(p);
m_currentPage = p;
if (!m_pages)
m_pages = m_currentPage;
m_next = start(m_currentPage);
}
void* LinearAllocator::alloc(size_t size)
{
size = ALIGN(size);
if (size > m_maxAllocSize && !fitsInCurrentPage(size)) {
ALOGV("Exceeded max size %d > %d", size, m_maxAllocSize);
// Allocation is too large, create a dedicated page for the allocation
Page* page = newPage(size);
m_dedicatedPageCount++;
page->setNext(m_pages);
m_pages = page;
if (!m_currentPage)
m_currentPage = m_pages;
return start(page);
}
ensureNext(size);
void* ptr = m_next;
m_next = ((char*)m_next) + size;
m_wastedSpace -= size;
return ptr;
}
void LinearAllocator::rewindIfLastAlloc(void* ptr, size_t allocSize)
{
// Don't bother rewinding across pages
if (ptr >= start(m_currentPage) && ptr < end(m_currentPage)
&& ptr == ((char*)m_next - allocSize)) {
m_totalAllocated -= allocSize;
m_wastedSpace += allocSize;
m_next = ptr;
}
}
LinearAllocator::Page* LinearAllocator::newPage(size_t pageSize)
{
pageSize += sizeof(LinearAllocator::Page);
ADD_ALLOCATION(pageSize);
m_totalAllocated += pageSize;
m_pageCount++;
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(m_totalAllocated, prettySize);
ALOGD("%sTotal allocated: %.2f%s", prefix, prettySize, prettySuffix);
prettySuffix = toSize(m_wastedSpace, prettySize);
ALOGD("%sWasted space: %.2f%s (%.1f%%)", prefix, prettySize, prettySuffix,
(float) m_wastedSpace / (float) m_totalAllocated * 100.0f);
ALOGD("%sPages %d (dedicated %d)", prefix, m_pageCount, m_dedicatedPageCount);
}
} // namespace WebCore
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