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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().
33 lines
960 B
C++
33 lines
960 B
C++
/*
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* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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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 <Kernel/Devices/CharacterDevice.h>
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namespace Kernel {
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class NullDevice final : public CharacterDevice {
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friend class DeviceManagement;
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public:
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virtual ~NullDevice() override;
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static NonnullRefPtr<NullDevice> must_initialize();
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private:
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NullDevice();
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// ^CharacterDevice
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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;
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virtual bool can_write(const OpenFileDescription&, size_t) const override { return true; }
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virtual bool can_read(const OpenFileDescription&, size_t) const override;
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virtual StringView class_name() const override { return "NullDevice"sv; }
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virtual bool is_seekable() const override { return true; }
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};
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}
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