| /* |
| * Copyright (C) 2014-2019 Apple Inc. All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. 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 APPLE INC. ``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 APPLE INC. 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. |
| */ |
| |
| #include "HeapConstants.h" |
| #include <algorithm> |
| |
| namespace bmalloc { |
| |
| DEFINE_STATIC_PER_PROCESS_STORAGE(HeapConstants); |
| |
| HeapConstants::HeapConstants(const LockHolder&) |
| : m_vmPageSizePhysical { vmPageSizePhysical() } |
| { |
| RELEASE_BASSERT(m_vmPageSizePhysical >= smallPageSize); |
| RELEASE_BASSERT(vmPageSize() >= m_vmPageSizePhysical); |
| |
| initializeLineMetadata(); |
| initializePageMetadata(); |
| } |
| |
| template <class C> |
| constexpr void fillLineMetadata(C& container, size_t VMPageSize) |
| { |
| constexpr size_t clsCount = sizeClass(smallLineSize); |
| size_t lineCount = smallLineCount(VMPageSize); |
| |
| for (size_t cls = 0; cls < clsCount; ++cls) { |
| size_t size = objectSize(cls); |
| size_t baseIndex = cls * lineCount; |
| size_t object = 0; |
| while (object < VMPageSize) { |
| size_t line = object / smallLineSize; |
| size_t leftover = object % smallLineSize; |
| |
| auto objectCount = divideRoundingUp(smallLineSize - leftover, size); |
| |
| object += objectCount * size; |
| |
| // Don't allow the last object in a page to escape the page. |
| if (object > VMPageSize) { |
| BASSERT(objectCount); |
| --objectCount; |
| } |
| |
| container[baseIndex + line] = { static_cast<unsigned char>(leftover), static_cast<unsigned char>(objectCount) }; |
| } |
| } |
| } |
| |
| template <size_t VMPageSize> |
| constexpr auto computeLineMetadata() |
| { |
| std::array<LineMetadata, sizeClass(smallLineSize) * smallLineCount(VMPageSize)> result; |
| fillLineMetadata(result, VMPageSize); |
| return result; |
| } |
| |
| #if BUSE(PRECOMPUTED_CONSTANTS_VMPAGE4K) |
| constexpr auto kPrecalcuratedLineMetadata4k = computeLineMetadata<4 * kB>(); |
| #endif |
| |
| #if BUSE(PRECOMPUTED_CONSTANTS_VMPAGE16K) |
| constexpr auto kPrecalcuratedLineMetadata16k = computeLineMetadata<16 * kB>(); |
| #endif |
| |
| void HeapConstants::initializeLineMetadata() |
| { |
| #if BUSE(PRECOMPUTED_CONSTANTS_VMPAGE4K) |
| if (m_vmPageSizePhysical == 4 * kB) { |
| m_smallLineMetadata = &kPrecalcuratedLineMetadata4k[0]; |
| return; |
| } |
| #endif |
| |
| #if BUSE(PRECOMPUTED_CONSTANTS_VMPAGE16K) |
| if (m_vmPageSizePhysical == 16 * kB) { |
| m_smallLineMetadata = &kPrecalcuratedLineMetadata16k[0]; |
| return; |
| } |
| #endif |
| |
| size_t sizeClassCount = bmalloc::sizeClass(smallLineSize); |
| m_smallLineMetadataStorage.grow(sizeClassCount * smallLineCount()); |
| fillLineMetadata(m_smallLineMetadataStorage, m_vmPageSizePhysical); |
| m_smallLineMetadata = &m_smallLineMetadataStorage[0]; |
| } |
| |
| void HeapConstants::initializePageMetadata() |
| { |
| auto computePageSize = [&](size_t sizeClass) { |
| size_t size = objectSize(sizeClass); |
| if (sizeClass < bmalloc::sizeClass(smallLineSize)) |
| return m_vmPageSizePhysical; |
| |
| for (size_t pageSize = m_vmPageSizePhysical; pageSize < pageSizeMax; pageSize += m_vmPageSizePhysical) { |
| RELEASE_BASSERT(pageSize <= chunkSize / 2); |
| size_t waste = pageSize % size; |
| if (waste <= pageSize / pageSizeWasteFactor) |
| return pageSize; |
| } |
| |
| return pageSizeMax; |
| }; |
| |
| for (size_t i = 0; i < sizeClassCount; ++i) |
| m_pageClasses[i] = (computePageSize(i) - 1) / smallPageSize; |
| } |
| |
| } // namespace bmalloc |