serenity/Kernel/TTY/PTYMultiplexer.h
Andreas Kling ac7ce12123 Kernel: Remove the kmalloc_eternal heap :^)
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().
2021-12-28 21:02:38 +01:00

43 lines
1.3 KiB
C++

/*
* Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/Badge.h>
#include <Kernel/Devices/CharacterDevice.h>
#include <Kernel/Locking/Mutex.h>
namespace Kernel {
class MasterPTY;
class PTYMultiplexer final : public CharacterDevice {
public:
PTYMultiplexer();
virtual ~PTYMultiplexer() override;
static void initialize();
static PTYMultiplexer& the();
// ^CharacterDevice
virtual ErrorOr<NonnullRefPtr<OpenFileDescription>> open(int options) override;
virtual ErrorOr<size_t> read(OpenFileDescription&, u64, UserOrKernelBuffer&, size_t) override { return 0; }
virtual ErrorOr<size_t> write(OpenFileDescription&, u64, const UserOrKernelBuffer&, size_t) override { return 0; }
virtual bool can_read(const OpenFileDescription&, size_t) const override { return true; }
virtual bool can_write(const OpenFileDescription&, size_t) const override { return true; }
void notify_master_destroyed(Badge<MasterPTY>, unsigned index);
private:
// ^CharacterDevice
virtual StringView class_name() const override { return "PTYMultiplexer"sv; }
static constexpr size_t max_pty_pairs = 64;
MutexProtected<Vector<unsigned, max_pty_pairs>> m_freelist;
};
}