e6a7723f2f
This will be useful when implementing mutex priority inheritance.
80 lines
2.1 KiB
C++
80 lines
2.1 KiB
C++
// Copyright 2014 Citra Emulator Project
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// Licensed under GPLv2 or any later version
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// Refer to the license.txt file included.
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#include <map>
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#include <vector>
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#include <boost/range/algorithm_ext/erase.hpp>
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#include "common/assert.h"
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#include "core/hle/kernel/kernel.h"
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#include "core/hle/kernel/mutex.h"
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#include "core/hle/kernel/thread.h"
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namespace Kernel {
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/**
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* Resumes a thread waiting for the specified mutex
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* @param mutex The mutex that some thread is waiting on
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*/
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static void ResumeWaitingThread(Mutex* mutex) {
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// Reset mutex lock thread handle, nothing is waiting
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mutex->lock_count = 0;
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mutex->holding_thread = nullptr;
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mutex->WakeupAllWaitingThreads();
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}
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void ReleaseThreadMutexes(Thread* thread) {
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for (auto& mtx : thread->held_mutexes) {
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ResumeWaitingThread(mtx.get());
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}
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thread->held_mutexes.clear();
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}
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Mutex::Mutex() {}
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Mutex::~Mutex() {}
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SharedPtr<Mutex> Mutex::Create(bool initial_locked, std::string name) {
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SharedPtr<Mutex> mutex(new Mutex);
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mutex->lock_count = 0;
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mutex->name = std::move(name);
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mutex->holding_thread = nullptr;
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// Acquire mutex with current thread if initialized as locked
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if (initial_locked)
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mutex->Acquire(GetCurrentThread());
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return mutex;
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}
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bool Mutex::ShouldWait(Thread* thread) const {
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return lock_count > 0 && thread != holding_thread;
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}
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void Mutex::Acquire(Thread* thread) {
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ASSERT_MSG(!ShouldWait(thread), "object unavailable!");
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// Actually "acquire" the mutex only if we don't already have it...
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if (lock_count == 0) {
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thread->held_mutexes.insert(this);
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holding_thread = std::move(thread);
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}
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lock_count++;
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}
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void Mutex::Release() {
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// Only release if the mutex is held...
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if (lock_count > 0) {
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lock_count--;
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// Yield to the next thread only if we've fully released the mutex...
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if (lock_count == 0) {
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holding_thread->held_mutexes.erase(this);
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ResumeWaitingThread(this);
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Core::System::GetInstance().PrepareReschedule();
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}
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}
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}
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} // namespace
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