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ac7ce12123
This was a premature optimization from the early days of SerenityOS. The eternal heap was a simple bump pointer allocator over a static byte array. My original idea was to avoid heap fragmentation and improve data locality, but both ideas were rooted in cargo culting, not data. We would reserve 4 MiB at boot and only ended up using ~256 KiB, wasting the rest. This patch replaces all kmalloc_eternal() usage by regular kmalloc().
40 lines
1.3 KiB
C++
40 lines
1.3 KiB
C++
/*
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* Copyright (c) 2021, Liav A. <liavalb@hotmail.co.il>
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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 <Kernel/Devices/CharacterDevice.h>
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#include <Kernel/PhysicalAddress.h>
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namespace Kernel {
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class MemoryDevice final : public CharacterDevice {
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friend class DeviceManagement;
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public:
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static NonnullRefPtr<MemoryDevice> must_create();
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~MemoryDevice();
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virtual ErrorOr<Memory::Region*> mmap(Process&, OpenFileDescription&, Memory::VirtualRange const&, u64 offset, int prot, bool shared) override;
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private:
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MemoryDevice();
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virtual StringView class_name() const override { return "MemoryDevice"sv; }
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virtual bool can_read(const OpenFileDescription&, size_t) const override { return true; }
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virtual bool can_write(const OpenFileDescription&, size_t) const override { return false; }
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virtual bool is_seekable() const override { return true; }
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virtual ErrorOr<size_t> read(OpenFileDescription&, u64, UserOrKernelBuffer&, size_t) override;
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virtual ErrorOr<size_t> write(OpenFileDescription&, u64, const UserOrKernelBuffer&, size_t) override { return EINVAL; }
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virtual void did_seek(OpenFileDescription&, off_t) override;
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bool is_allowed_range(PhysicalAddress, Memory::VirtualRange const&) const;
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};
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}
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