Add LinearAllocator

Moving from external/webkit/Source/WebCore/platform/graphics/android/utils/

Change-Id: If91830aa9b207dbc8692b2ca7c4a0b76778addd5

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 <stddef.h>
+
+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

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

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 <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