suyu/src/core/hle/kernel/scheduler.cpp
Lioncash 5c0408596f kernel/thread: Use a regular pointer for the owner/current process
There's no real need to use a shared pointer in these cases, and only
makes object management more fragile in terms of how easy it would be to
introduce cycles. Instead, just do the simple thing of using a regular
pointer. Much of this is just a hold-over from citra anyways.

It also doesn't make sense from a behavioral point of view for a
process' thread to prolong the lifetime of the process itself (the
process is supposed to own the thread, not the other way around).
2018-10-10 02:04:55 -04:00

160 lines
5.1 KiB
C++

// Copyright 2018 yuzu emulator team
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#include <algorithm>
#include <utility>
#include "common/assert.h"
#include "common/logging/log.h"
#include "core/arm/arm_interface.h"
#include "core/core.h"
#include "core/hle/kernel/kernel.h"
#include "core/hle/kernel/process.h"
#include "core/hle/kernel/scheduler.h"
namespace Kernel {
std::mutex Scheduler::scheduler_mutex;
Scheduler::Scheduler(Core::ARM_Interface& cpu_core) : cpu_core(cpu_core) {}
Scheduler::~Scheduler() {
for (auto& thread : thread_list) {
thread->Stop();
}
}
bool Scheduler::HaveReadyThreads() const {
std::lock_guard<std::mutex> lock(scheduler_mutex);
return ready_queue.get_first() != nullptr;
}
Thread* Scheduler::GetCurrentThread() const {
return current_thread.get();
}
Thread* Scheduler::PopNextReadyThread() {
Thread* next = nullptr;
Thread* thread = GetCurrentThread();
if (thread && thread->GetStatus() == ThreadStatus::Running) {
// We have to do better than the current thread.
// This call returns null when that's not possible.
next = ready_queue.pop_first_better(thread->GetPriority());
if (!next) {
// Otherwise just keep going with the current thread
next = thread;
}
} else {
next = ready_queue.pop_first();
}
return next;
}
void Scheduler::SwitchContext(Thread* new_thread) {
Thread* previous_thread = GetCurrentThread();
// Save context for previous thread
if (previous_thread) {
cpu_core.SaveContext(previous_thread->GetContext());
// Save the TPIDR_EL0 system register in case it was modified.
previous_thread->SetTPIDR_EL0(cpu_core.GetTPIDR_EL0());
if (previous_thread->GetStatus() == ThreadStatus::Running) {
// This is only the case when a reschedule is triggered without the current thread
// yielding execution (i.e. an event triggered, system core time-sliced, etc)
ready_queue.push_front(previous_thread->GetPriority(), previous_thread);
previous_thread->SetStatus(ThreadStatus::Ready);
}
}
// Load context of new thread
if (new_thread) {
ASSERT_MSG(new_thread->GetStatus() == ThreadStatus::Ready,
"Thread must be ready to become running.");
// Cancel any outstanding wakeup events for this thread
new_thread->CancelWakeupTimer();
auto* const previous_process = Core::CurrentProcess();
current_thread = new_thread;
ready_queue.remove(new_thread->GetPriority(), new_thread);
new_thread->SetStatus(ThreadStatus::Running);
auto* const thread_owner_process = current_thread->GetOwnerProcess();
if (previous_process != thread_owner_process) {
Core::System::GetInstance().Kernel().MakeCurrentProcess(thread_owner_process);
SetCurrentPageTable(&Core::CurrentProcess()->VMManager().page_table);
}
cpu_core.LoadContext(new_thread->GetContext());
cpu_core.SetTlsAddress(new_thread->GetTLSAddress());
cpu_core.SetTPIDR_EL0(new_thread->GetTPIDR_EL0());
cpu_core.ClearExclusiveState();
} else {
current_thread = nullptr;
// Note: We do not reset the current process and current page table when idling because
// technically we haven't changed processes, our threads are just paused.
}
}
void Scheduler::Reschedule() {
std::lock_guard<std::mutex> lock(scheduler_mutex);
Thread* cur = GetCurrentThread();
Thread* next = PopNextReadyThread();
if (cur && next) {
LOG_TRACE(Kernel, "context switch {} -> {}", cur->GetObjectId(), next->GetObjectId());
} else if (cur) {
LOG_TRACE(Kernel, "context switch {} -> idle", cur->GetObjectId());
} else if (next) {
LOG_TRACE(Kernel, "context switch idle -> {}", next->GetObjectId());
}
SwitchContext(next);
}
void Scheduler::AddThread(SharedPtr<Thread> thread, u32 priority) {
std::lock_guard<std::mutex> lock(scheduler_mutex);
thread_list.push_back(std::move(thread));
ready_queue.prepare(priority);
}
void Scheduler::RemoveThread(Thread* thread) {
std::lock_guard<std::mutex> lock(scheduler_mutex);
thread_list.erase(std::remove(thread_list.begin(), thread_list.end(), thread),
thread_list.end());
}
void Scheduler::ScheduleThread(Thread* thread, u32 priority) {
std::lock_guard<std::mutex> lock(scheduler_mutex);
ASSERT(thread->GetStatus() == ThreadStatus::Ready);
ready_queue.push_back(priority, thread);
}
void Scheduler::UnscheduleThread(Thread* thread, u32 priority) {
std::lock_guard<std::mutex> lock(scheduler_mutex);
ASSERT(thread->GetStatus() == ThreadStatus::Ready);
ready_queue.remove(priority, thread);
}
void Scheduler::SetThreadPriority(Thread* thread, u32 priority) {
std::lock_guard<std::mutex> lock(scheduler_mutex);
// If thread was ready, adjust queues
if (thread->GetStatus() == ThreadStatus::Ready)
ready_queue.move(thread, thread->GetPriority(), priority);
else
ready_queue.prepare(priority);
}
} // namespace Kernel