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// 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/core_timing.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();
}
u64 Scheduler::GetLastContextSwitchTicks() const {
return last_context_switch_time;
}
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* const previous_thread = GetCurrentThread();
Process* const previous_process = Core::CurrentProcess();
UpdateLastContextSwitchTime(previous_thread, previous_process);
// 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();
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::UpdateLastContextSwitchTime(Thread* thread, Process* process) {
const u64 prev_switch_ticks = last_context_switch_time;
const u64 most_recent_switch_ticks = CoreTiming::GetTicks();
const u64 update_ticks = most_recent_switch_ticks - prev_switch_ticks;
if (thread != nullptr) {
thread->UpdateCPUTimeTicks(update_ticks);
}
if (process != nullptr) {
process->UpdateCPUTimeTicks(update_ticks);
}
last_context_switch_time = most_recent_switch_ticks;
}
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
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