ladybird/Libraries/LibGC/BlockAllocator.h

/*
 * Copyright (c) 2021-2023, Andreas Kling <andreas@ladybird.org>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#pragma once

#include <AK/Vector.h>
#include <LibGC/Forward.h>

namespace GC {

class BlockAllocator {
public:
    BlockAllocator() = default;
    ~BlockAllocator();

    void* allocate_block(char const* name);
    void deallocate_block(void*);

private:
    Vector<void*> m_blocks;
};

}
LibJS: Recycle up to 64 HeapBlocks to improve performance :^) This patch adds a BlockAllocator to the GC heap where we now cache up to 64 HeapBlock-sized mmap's that get recycled when allocating HeapBlocks. This improves test-js runtime performance by ~35%, pretty cool! :^) 2021-05-27 17:01:26 +00:00			`/*`
Meta: Update my e-mail address everywhere 2024-10-04 11:19:50 +00:00			`* Copyright (c) 2021-2023, Andreas Kling <andreas@ladybird.org>`
LibJS: Recycle up to 64 HeapBlocks to improve performance :^) This patch adds a BlockAllocator to the GC heap where we now cache up to 64 HeapBlock-sized mmap's that get recycled when allocating HeapBlocks. This improves test-js runtime performance by ~35%, pretty cool! :^) 2021-05-27 17:01:26 +00:00			`*`
			`* SPDX-License-Identifier: BSD-2-Clause`
			`*/`

			`#pragma once`

			`#include <AK/Vector.h>`
LibGC+Everywhere: Factor out a LibGC from LibJS Resulting in a massive rename across almost everywhere! Alongside the namespace change, we now have the following names: * JS::NonnullGCPtr -> GC::Ref * JS::GCPtr -> GC::Ptr * JS::HeapFunction -> GC::Function * JS::CellImpl -> GC::Cell * JS::Handle -> GC::Root 2024-11-14 15:01:23 +00:00			`#include <LibGC/Forward.h>`
LibJS: Recycle up to 64 HeapBlocks to improve performance :^) This patch adds a BlockAllocator to the GC heap where we now cache up to 64 HeapBlock-sized mmap's that get recycled when allocating HeapBlocks. This improves test-js runtime performance by ~35%, pretty cool! :^) 2021-05-27 17:01:26 +00:00
LibGC+Everywhere: Factor out a LibGC from LibJS Resulting in a massive rename across almost everywhere! Alongside the namespace change, we now have the following names: * JS::NonnullGCPtr -> GC::Ref * JS::GCPtr -> GC::Ptr * JS::HeapFunction -> GC::Function * JS::CellImpl -> GC::Cell * JS::Handle -> GC::Root 2024-11-14 15:01:23 +00:00			`namespace GC {`
LibJS: Recycle up to 64 HeapBlocks to improve performance :^) This patch adds a BlockAllocator to the GC heap where we now cache up to 64 HeapBlock-sized mmap's that get recycled when allocating HeapBlocks. This improves test-js runtime performance by ~35%, pretty cool! :^) 2021-05-27 17:01:26 +00:00
			`class BlockAllocator {`
			`public:`
Libraries: Use default constructors/destructors in LibJS https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#cother-other-default-operation-rules "The compiler is more likely to get the default semantics right and you cannot implement these functions better than the compiler." 2022-03-14 16:25:06 +00:00			`BlockAllocator() = default;`
LibJS: Recycle up to 64 HeapBlocks to improve performance :^) This patch adds a BlockAllocator to the GC heap where we now cache up to 64 HeapBlock-sized mmap's that get recycled when allocating HeapBlocks. This improves test-js runtime performance by ~35%, pretty cool! :^) 2021-05-27 17:01:26 +00:00			`~BlockAllocator();`

			`void* allocate_block(char const* name);`
			`void deallocate_block(void*);`

			`private:`
LibJS: Never give back virtual memory once it belongs to a cell type Instead of returning HeapBlock memory to the kernel (or a non-type specific shared cache), we now keep a BlockAllocator per CellAllocator and implement "deallocation" by basically informing the kernel that we don't need the physical memory right now. This is done with MADV_FREE or MADV_DONTNEED if available, but for other platforms (including SerenityOS) we munmap and then re-mmap the memory to achieve the same effect. It's definitely clunky, so I've added a FIXME about implementing the madvise options on SerenityOS too. The important outcome of this change is that GC types that use a type-specific allocator become immune to use-after-free type confusion attacks, since their virtual addresses will only ever be re-used for the same exact type again and again. Fixes #22274 2023-12-31 10:36:18 +00:00			`Vector<void*> m_blocks;`
LibJS: Recycle up to 64 HeapBlocks to improve performance :^) This patch adds a BlockAllocator to the GC heap where we now cache up to 64 HeapBlock-sized mmap's that get recycled when allocating HeapBlocks. This improves test-js runtime performance by ~35%, pretty cool! :^) 2021-05-27 17:01:26 +00:00			`};`

			`}`