ladybird/Kernel/Scheduler.h
Tom 60a559af7e Kernel: Avoid unnecessary context switch when no other thread is ready
If no other thread is ready to be run we don't need to switch to the
idle thread and wait for the next timer interrupt. We can just give
the thread another timeslice and keep it running.
2021-07-12 10:19:31 +02:00

54 lines
1.5 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/Assertions.h>
#include <AK/Function.h>
#include <AK/IntrusiveList.h>
#include <AK/Types.h>
#include <Kernel/Forward.h>
#include <Kernel/SpinLock.h>
#include <Kernel/Time/TimeManagement.h>
#include <Kernel/UnixTypes.h>
namespace Kernel {
struct RegisterState;
extern Thread* g_finalizer;
extern WaitQueue* g_finalizer_wait_queue;
extern Atomic<bool> g_finalizer_has_work;
extern RecursiveSpinLock g_scheduler_lock;
class Scheduler {
public:
static void initialize();
static Thread* create_ap_idle_thread(u32 cpu);
static void set_idle_thread(Thread* idle_thread);
static void timer_tick(const RegisterState&);
[[noreturn]] static void start();
static bool pick_next();
static bool yield();
static void yield_from_critical();
static bool context_switch(Thread*);
static void enter_current(Thread& prev_thread, bool is_first);
static void leave_on_first_switch(u32 flags);
static void prepare_after_exec();
static void prepare_for_idle_loop();
static Process* colonel();
static void idle_loop(void*);
static void invoke_async();
static void notify_finalizer();
static Thread& pull_next_runnable_thread();
static Thread* peek_next_runnable_thread();
static bool dequeue_runnable_thread(Thread&, bool = false);
static void queue_runnable_thread(Thread&);
static void dump_scheduler_state();
static bool is_initialized();
};
}