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https://github.com/LadybirdBrowser/ladybird.git
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a6bf253602
Before this change, we were hard-coding 4 KiB. This meant that systems with a 16 KiB native page size were wasting 12 KiB per HeapBlock on nothing, leading to worse locality and more mmap/madvise churn. We now query the system page size on startup and use that as the HeapBlock size. The only downside here is that some of the pointer math for finding the base of a HeapBlock now has to use a runtime computed value instead of a compile time constant. But that's a small price to pay for what we get.
53 lines
914 B
C++
53 lines
914 B
C++
/*
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* Copyright (c) 2020-2024, Andreas Kling <andreas@ladybird.org>
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* Copyright (c) 2020-2023, the SerenityOS developers.
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#pragma once
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#include <AK/Types.h>
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#include <LibJS/Forward.h>
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namespace JS {
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class HeapBase {
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AK_MAKE_NONCOPYABLE(HeapBase);
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AK_MAKE_NONMOVABLE(HeapBase);
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public:
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VM& vm() { return m_vm; }
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protected:
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HeapBase(VM& vm)
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: m_vm(vm)
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{
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}
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VM& m_vm;
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};
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class HeapBlockBase {
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AK_MAKE_NONMOVABLE(HeapBlockBase);
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AK_MAKE_NONCOPYABLE(HeapBlockBase);
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public:
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static size_t block_size;
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static HeapBlockBase* from_cell(Cell const* cell)
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{
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return reinterpret_cast<HeapBlockBase*>(bit_cast<FlatPtr>(cell) & ~(HeapBlockBase::block_size - 1));
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}
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Heap& heap() { return m_heap; }
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protected:
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HeapBlockBase(Heap& heap)
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: m_heap(heap)
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{
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}
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Heap& m_heap;
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};
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}
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