PoolAlloc.cpp

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Author : Tobin Ehlis
Date : 2019-01-17 12:25:54
Hash : 5546fb4f
Message : Vulkan:Adding custom pool allocator Migrated pool allocator used by compiler to common. Planning to use this for ANGLE custom command buffers so this some refactoring in preparation for that work. Added a unit test to check PoolAllocator functionality. Bug: angleproject:2951 Reviewed-on: https://chromium-review.googlesource.com/c/1476953 Reviewed-by: Jamie Madill <jmadill@google.com> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Commit-Queue: Tobin Ehlis <tobine@google.com> Change-Id: I0b4f3d55ea1799e35c9799c221f7129233f30b24 Reviewed-on: https://chromium-review.googlesource.com/c/1492972
src/common/PoolAlloc.cpp
//
// Copyright 2019 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//
// PoolAlloc.cpp:
//    Implements the class methods for PoolAllocator and Allocation classes.
//

#include "common/PoolAlloc.h"

#include <assert.h>
#include <stdint.h>
#include <stdio.h>

#include "common/angleutils.h"
#include "common/debug.h"
#include "common/platform.h"
#include "common/tls.h"

namespace angle
{

//
// Implement the functionality of the PoolAllocator class, which
// is documented in PoolAlloc.h.
//
PoolAllocator::PoolAllocator(int growthIncrement, int allocationAlignment)
    : mAlignment(allocationAlignment),
#if !defined(ANGLE_DISABLE_POOL_ALLOC)
      mPageSize(growthIncrement),
      mFreeList(0),
      mInUseList(0),
      mNumCalls(0),
      mTotalBytes(0),
#endif
      mLocked(false)
{
    //
    // Adjust mAlignment to be at least pointer aligned and
    // power of 2.
    //
    size_t minAlign = sizeof(void *);
    mAlignment &= ~(minAlign - 1);
    if (mAlignment < minAlign)
        mAlignment = minAlign;
    size_t a = 1;
    while (a < mAlignment)
        a <<= 1;
    mAlignment     = a;
    mAlignmentMask = a - 1;

#if !defined(ANGLE_DISABLE_POOL_ALLOC)
    //
    // Don't allow page sizes we know are smaller than all common
    // OS page sizes.
    //
    if (mPageSize < 4 * 1024)
        mPageSize = 4 * 1024;

    //
    // A large mCurrentPageOffset indicates a new page needs to
    // be obtained to allocate memory.
    //
    mCurrentPageOffset = mPageSize;

    //
    // Align header skip
    //
    mHeaderSkip = minAlign;
    if (mHeaderSkip < sizeof(Header))
    {
        mHeaderSkip = (sizeof(Header) + mAlignmentMask) & ~mAlignmentMask;
    }
#else  // !defined(ANGLE_DISABLE_POOL_ALLOC)
    mStack.push_back({});
#endif
}

PoolAllocator::~PoolAllocator()
{
#if !defined(ANGLE_DISABLE_POOL_ALLOC)
    while (mInUseList)
    {
        Header *next = mInUseList->nextPage;
        mInUseList->~Header();
        delete[] reinterpret_cast<char *>(mInUseList);
        mInUseList = next;
    }
    // We should not check the guard blocks
    // here, because we did it already when the block was
    // placed into the free list.
    //
    while (mFreeList)
    {
        Header *next = mFreeList->nextPage;
        delete[] reinterpret_cast<char *>(mFreeList);
        mFreeList = next;
    }
#else  // !defined(ANGLE_DISABLE_POOL_ALLOC)
    for (auto &allocs : mStack)
    {
        for (auto alloc : allocs)
        {
            free(alloc);
        }
    }
    mStack.clear();
#endif
}

//
// Check a single guard block for damage
//
void Allocation::checkGuardBlock(unsigned char *blockMem,
                                 unsigned char val,
                                 const char *locText) const
{
#if defined(ANGLE_POOL_ALLOC_GUARD_BLOCKS)
    for (size_t x = 0; x < kGuardBlockSize; x++)
    {
        if (blockMem[x] != val)
        {
            char assertMsg[80];
            // We don't print the assert message.  It's here just to be helpful.
            snprintf(assertMsg, sizeof(assertMsg),
                     "PoolAlloc: Damage %s %zu byte allocation at 0x%p\n", locText, mSize, data());
            assert(0 && "PoolAlloc: Damage in guard block");
        }
    }
#endif
}

void PoolAllocator::push()
{
#if !defined(ANGLE_DISABLE_POOL_ALLOC)
    AllocState state = {mCurrentPageOffset, mInUseList};

    mStack.push_back(state);

    //
    // Indicate there is no current page to allocate from.
    //
    mCurrentPageOffset = mPageSize;
#else  // !defined(ANGLE_DISABLE_POOL_ALLOC)
    mStack.push_back({});
#endif
}

//
// Do a mass-deallocation of all the individual allocations
// that have occurred since the last push(), or since the
// last pop(), or since the object's creation.
//
// The deallocated pages are saved for future allocations.
//
void PoolAllocator::pop()
{
    if (mStack.size() < 1)
        return;

#if !defined(ANGLE_DISABLE_POOL_ALLOC)
    Header *page       = mStack.back().page;
    mCurrentPageOffset = mStack.back().offset;

    while (mInUseList != page)
    {
        // invoke destructor to free allocation list
        mInUseList->~Header();

        Header *nextInUse = mInUseList->nextPage;
        if (mInUseList->pageCount > 1)
            delete[] reinterpret_cast<char *>(mInUseList);
        else
        {
            mInUseList->nextPage = mFreeList;
            mFreeList            = mInUseList;
        }
        mInUseList = nextInUse;
    }

    mStack.pop_back();
#else  // !defined(ANGLE_DISABLE_POOL_ALLOC)
    for (auto &alloc : mStack.back())
    {
        free(alloc);
    }
    mStack.pop_back();
#endif
}

//
// Do a mass-deallocation of all the individual allocations
// that have occurred.
//
void PoolAllocator::popAll()
{
    while (mStack.size() > 0)
        pop();
}

void *PoolAllocator::allocate(size_t numBytes)
{
    ASSERT(!mLocked);

#if !defined(ANGLE_DISABLE_POOL_ALLOC)
    //
    // Just keep some interesting statistics.
    //
    ++mNumCalls;
    mTotalBytes += numBytes;

    // If we are using guard blocks, all allocations are bracketed by
    // them: [guardblock][allocation][guardblock].  numBytes is how
    // much memory the caller asked for.  allocationSize is the total
    // size including guard blocks.  In release build,
    // kGuardBlockSize=0 and this all gets optimized away.
    size_t allocationSize = Allocation::AllocationSize(numBytes) + mAlignment;
    // Detect integer overflow.
    if (allocationSize < numBytes)
        return 0;

    //
    // Do the allocation, most likely case first, for efficiency.
    // This step could be moved to be inline sometime.
    //
    if (allocationSize <= mPageSize - mCurrentPageOffset)
    {
        //
        // Safe to allocate from mCurrentPageOffset.
        //
        unsigned char *memory = reinterpret_cast<unsigned char *>(mInUseList) + mCurrentPageOffset;
        mCurrentPageOffset += allocationSize;
        mCurrentPageOffset = (mCurrentPageOffset + mAlignmentMask) & ~mAlignmentMask;

        return initializeAllocation(mInUseList, memory, numBytes);
    }

    if (allocationSize > mPageSize - mHeaderSkip)
    {
        //
        // Do a multi-page allocation.  Don't mix these with the others.
        // The OS is efficient in allocating and freeing multiple pages.
        //
        size_t numBytesToAlloc = allocationSize + mHeaderSkip;
        // Detect integer overflow.
        if (numBytesToAlloc < allocationSize)
            return 0;

        Header *memory = reinterpret_cast<Header *>(::new char[numBytesToAlloc]);
        if (memory == 0)
            return 0;

        // Use placement-new to initialize header
        new (memory) Header(mInUseList, (numBytesToAlloc + mPageSize - 1) / mPageSize);
        mInUseList = memory;

        mCurrentPageOffset = mPageSize;  // make next allocation come from a new page

        // No guard blocks for multi-page allocations (yet)
        void *unalignedPtr =
            reinterpret_cast<void *>(reinterpret_cast<uintptr_t>(memory) + mHeaderSkip);
        return std::align(mAlignment, numBytes, unalignedPtr, allocationSize);
    }

    //
    // Need a simple page to allocate from.
    //
    Header *memory;
    if (mFreeList)
    {
        memory    = mFreeList;
        mFreeList = mFreeList->nextPage;
    }
    else
    {
        memory = reinterpret_cast<Header *>(::new char[mPageSize]);
        if (memory == 0)
            return 0;
    }

    // Use placement-new to initialize header
    new (memory) Header(mInUseList, 1);
    mInUseList = memory;

    unsigned char *ret = reinterpret_cast<unsigned char *>(mInUseList) + mHeaderSkip;
    mCurrentPageOffset = (mHeaderSkip + allocationSize + mAlignmentMask) & ~mAlignmentMask;
    return initializeAllocation(mInUseList, ret, numBytes);
#else  // !defined(ANGLE_DISABLE_POOL_ALLOC)
    void *alloc = malloc(numBytes + mAlignmentMask);
    mStack.back().push_back(alloc);

    intptr_t intAlloc = reinterpret_cast<intptr_t>(alloc);
    intAlloc          = (intAlloc + mAlignmentMask) & ~mAlignmentMask;
    return reinterpret_cast<void *>(intAlloc);
#endif
}

void PoolAllocator::lock()
{
    ASSERT(!mLocked);
    mLocked = true;
}

void PoolAllocator::unlock()
{
    ASSERT(mLocked);
    mLocked = false;
}

//
// Check all allocations in a list for damage by calling check on each.
//
void Allocation::checkAllocList() const
{
    for (const Allocation *alloc = this; alloc != 0; alloc = alloc->mPrevAlloc)
        alloc->check();
}

}  // namespace angle
kc3-lang/angle/src/common/PoolAlloc.cpp

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kc3-lang/angle /src/common/PoolAlloc.cpp
