// Copyright 2020 yuzu Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
// This file references various implementation details from Atmosphere, an open-source firmware for
// the Nintendo Switch. Copyright 2018-2020 Atmosphere-NX.
#include "common/assert.h"
#include "common/bit_util.h"
#include "common/fiber.h"
#include "common/logging/log.h"
#include "core/arm/arm_interface.h"
#include "core/core.h"
#include "core/core_timing.h"
#include "core/cpu_manager.h"
#include "core/hle/kernel/k_scheduler.h"
#include "core/hle/kernel/kernel.h"
#include "core/hle/kernel/physical_core.h"
#include "core/hle/kernel/process.h"
#include "core/hle/kernel/thread.h"
#include "core/hle/kernel/time_manager.h"
namespace Kernel {
static void IncrementScheduledCount(Kernel::Thread* thread) {
if (auto process = thread->GetOwnerProcess(); process) {
process->IncrementScheduledCount();
}
}
/*static*/ void KScheduler::RescheduleCores(KernelCore& kernel, u64 cores_pending_reschedule,
Core::EmuThreadHandle global_thread) {
u32 current_core = global_thread.host_handle;
bool must_context_switch = global_thread.guest_handle != InvalidHandle &&
(current_core < Core::Hardware::NUM_CPU_CORES);
while (cores_pending_reschedule != 0) {
u32 core = Common::CountTrailingZeroes64(cores_pending_reschedule);
ASSERT(core < Core::Hardware::NUM_CPU_CORES);
if (!must_context_switch || core != current_core) {
auto& phys_core = kernel.PhysicalCore(core);
phys_core.Interrupt();
} else {
must_context_switch = true;
}
cores_pending_reschedule &= ~(1ULL << core);
}
if (must_context_switch) {
auto core_scheduler = kernel.CurrentScheduler();
kernel.ExitSVCProfile();
core_scheduler->RescheduleCurrentCore();
kernel.EnterSVCProfile();
}
}
u64 KScheduler::UpdateHighestPriorityThread(Thread* highest_thread) {
std::scoped_lock lock{guard};
if (Thread* prev_highest_thread = this->state.highest_priority_thread;
prev_highest_thread != highest_thread) {
if (prev_highest_thread != nullptr) {
IncrementScheduledCount(prev_highest_thread);
prev_highest_thread->SetLastScheduledTick(system.CoreTiming().GetCPUTicks());
}
if (this->state.should_count_idle) {
if (highest_thread != nullptr) {
// if (Process* process = highest_thread->GetOwnerProcess(); process != nullptr) {
// process->SetRunningThread(this->core_id, highest_thread,
// this->state.idle_count);
//}
} else {
this->state.idle_count++;
}
}
this->state.highest_priority_thread = highest_thread;
this->state.needs_scheduling = true;
return (1ULL << this->core_id);
} else {
return 0;
}
}
/*static*/ u64 KScheduler::UpdateHighestPriorityThreadsImpl(KernelCore& kernel) {
ASSERT(kernel.GlobalSchedulerContext().IsLocked());
/* Clear that we need to update. */
ClearSchedulerUpdateNeeded(kernel);
u64 cores_needing_scheduling = 0, idle_cores = 0;
Thread* top_threads[Core::Hardware::NUM_CPU_CORES];
auto& priority_queue = GetPriorityQueue(kernel);
/* We want to go over all cores, finding the highest priority thread and determining if
* scheduling is needed for that core. */
for (size_t core_id = 0; core_id < Core::Hardware::NUM_CPU_CORES; core_id++) {
Thread* top_thread = priority_queue.GetScheduledFront((s32)core_id);
if (top_thread != nullptr) {
///* If the thread has no waiters, we need to check if the process has a thread pinned.
///*/
// if (top_thread->GetNumKernelWaiters() == 0) {
// if (Process* parent = top_thread->GetOwnerProcess(); parent != nullptr) {
// if (Thread* pinned = parent->GetPinnedThread(core_id);
// pinned != nullptr && pinned != top_thread) {
// /* We prefer our parent's pinned thread if possible. However, we also
// don't
// * want to schedule un-runnable threads. */
// if (pinned->GetRawState() == Thread::ThreadState_Runnable) {
// top_thread = pinned;
// } else {
// top_thread = nullptr;
// }
// }
// }
//}
} else {
idle_cores |= (1ULL << core_id);
}
top_threads[core_id] = top_thread;
cores_needing_scheduling |=
kernel.Scheduler(core_id).UpdateHighestPriorityThread(top_threads[core_id]);
}
/* Idle cores are bad. We're going to try to migrate threads to each idle core in turn. */
while (idle_cores != 0) {
u32 core_id = Common::CountTrailingZeroes64(idle_cores);
if (Thread* suggested = priority_queue.GetSuggestedFront(core_id); suggested != nullptr) {
s32 migration_candidates[Core::Hardware::NUM_CPU_CORES];
size_t num_candidates = 0;
/* While we have a suggested thread, try to migrate it! */
while (suggested != nullptr) {
/* Check if the suggested thread is the top thread on its core. */
const s32 suggested_core = suggested->GetActiveCore();
if (Thread* top_thread =
(suggested_core >= 0) ? top_threads[suggested_core] : nullptr;
top_thread != suggested) {
/* Make sure we're not dealing with threads too high priority for migration. */
if (top_thread != nullptr &&
top_thread->GetPriority() < HighestCoreMigrationAllowedPriority) {
break;
}
/* The suggested thread isn't bound to its core, so we can migrate it! */
suggested->SetActiveCore(core_id);
priority_queue.ChangeCore(suggested_core, suggested);
top_threads[core_id] = suggested;
cores_needing_scheduling |=
kernel.Scheduler(core_id).UpdateHighestPriorityThread(top_threads[core_id]);
break;
}
/* Note this core as a candidate for migration. */
ASSERT(num_candidates < Core::Hardware::NUM_CPU_CORES);
migration_candidates[num_candidates++] = suggested_core;
suggested = priority_queue.GetSuggestedNext(core_id, suggested);
}
/* If suggested is nullptr, we failed to migrate a specific thread. So let's try all our
* candidate cores' top threads. */
if (suggested == nullptr) {
for (size_t i = 0; i < num_candidates; i++) {
/* Check if there's some other thread that can run on the candidate core. */
const s32 candidate_core = migration_candidates[i];
suggested = top_threads[candidate_core];
if (Thread* next_on_candidate_core =
priority_queue.GetScheduledNext(candidate_core, suggested);
next_on_candidate_core != nullptr) {
/* The candidate core can run some other thread! We'll migrate its current
* top thread to us. */
top_threads[candidate_core] = next_on_candidate_core;
cores_needing_scheduling |=
kernel.Scheduler(candidate_core)
.UpdateHighestPriorityThread(top_threads[candidate_core]);
/* Perform the migration. */
suggested->SetActiveCore(core_id);
priority_queue.ChangeCore(candidate_core, suggested);
top_threads[core_id] = suggested;
cores_needing_scheduling |=
kernel.Scheduler(core_id).UpdateHighestPriorityThread(
top_threads[core_id]);
break;
}
}
}
}
idle_cores &= ~(1ULL << core_id);
}
return cores_needing_scheduling;
}
/*static*/ void KScheduler::OnThreadStateChanged(KernelCore& kernel, Thread* thread,
u32 old_state) {
ASSERT(kernel.GlobalSchedulerContext().IsLocked());
/* Check if the state has changed, because if it hasn't there's nothing to do. */
const auto cur_state = thread->scheduling_state;
if (cur_state == old_state) {
return;
}
/* Update the priority queues. */
if (old_state == static_cast<u32>(ThreadSchedStatus::Runnable)) {
/* If we were previously runnable, then we're not runnable now, and we should remove. */
GetPriorityQueue(kernel).Remove(thread);
IncrementScheduledCount(thread);
SetSchedulerUpdateNeeded(kernel);
} else if (cur_state == static_cast<u32>(ThreadSchedStatus::Runnable)) {
/* If we're now runnable, then we weren't previously, and we should add. */
GetPriorityQueue(kernel).PushBack(thread);
IncrementScheduledCount(thread);
SetSchedulerUpdateNeeded(kernel);
}
}
/*static*/ void KScheduler::OnThreadPriorityChanged(KernelCore& kernel, Thread* thread,
Thread* current_thread, u32 old_priority) {
ASSERT(kernel.GlobalSchedulerContext().IsLocked());
/* If the thread is runnable, we want to change its priority in the queue. */
if (thread->scheduling_state == static_cast<u32>(ThreadSchedStatus::Runnable)) {
GetPriorityQueue(kernel).ChangePriority(
old_priority, thread == kernel.CurrentScheduler()->GetCurrentThread(), thread);
IncrementScheduledCount(thread);
SetSchedulerUpdateNeeded(kernel);
}
}
/*static*/ void KScheduler::OnThreadAffinityMaskChanged(KernelCore& kernel, Thread* thread,
const KAffinityMask& old_affinity,
s32 old_core) {
ASSERT(kernel.GlobalSchedulerContext().IsLocked());
/* If the thread is runnable, we want to change its affinity in the queue. */
if (thread->scheduling_state == static_cast<u32>(ThreadSchedStatus::Runnable)) {
GetPriorityQueue(kernel).ChangeAffinityMask(old_core, old_affinity, thread);
IncrementScheduledCount(thread);
SetSchedulerUpdateNeeded(kernel);
}
}
void KScheduler::RotateScheduledQueue(s32 core_id, s32 priority) {
ASSERT(system.GlobalSchedulerContext().IsLocked());
/* Get a reference to the priority queue. */
auto& kernel = system.Kernel();
auto& priority_queue = GetPriorityQueue(kernel);
/* Rotate the front of the queue to the end. */
Thread* top_thread = priority_queue.GetScheduledFront(core_id, priority);
Thread* next_thread = nullptr;
if (top_thread != nullptr) {
next_thread = priority_queue.MoveToScheduledBack(top_thread);
if (next_thread != top_thread) {
IncrementScheduledCount(top_thread);
IncrementScheduledCount(next_thread);
}
}
/* While we have a suggested thread, try to migrate it! */
{
Thread* suggested = priority_queue.GetSuggestedFront(core_id, priority);
while (suggested != nullptr) {
/* Check if the suggested thread is the top thread on its core. */
const s32 suggested_core = suggested->GetActiveCore();
if (Thread* top_on_suggested_core =
(suggested_core >= 0) ? priority_queue.GetScheduledFront(suggested_core)
: nullptr;
top_on_suggested_core != suggested) {
/* If the next thread is a new thread that has been waiting longer than our
* suggestion, we prefer it to our suggestion. */
if (top_thread != next_thread && next_thread != nullptr &&
next_thread->GetLastScheduledTick() < suggested->GetLastScheduledTick()) {
suggested = nullptr;
break;
}
/* If we're allowed to do a migration, do one. */
/* NOTE: Unlike migrations in UpdateHighestPriorityThread, this moves the suggestion
* to the front of the queue. */
if (top_on_suggested_core == nullptr ||
top_on_suggested_core->GetPriority() >= HighestCoreMigrationAllowedPriority) {
suggested->SetActiveCore(core_id);
priority_queue.ChangeCore(suggested_core, suggested, true);
IncrementScheduledCount(suggested);
break;
}
}
/* Get the next suggestion. */
suggested = priority_queue.GetSamePriorityNext(core_id, suggested);
}
}
/* Now that we might have migrated a thread with the same priority, check if we can do better.
*/
{
Thread* best_thread = priority_queue.GetScheduledFront(core_id);
if (best_thread == GetCurrentThread()) {
best_thread = priority_queue.GetScheduledNext(core_id, best_thread);
}
/* If the best thread we can choose has a priority the same or worse than ours, try to
* migrate a higher priority thread. */
if (best_thread != nullptr && best_thread->GetPriority() >= static_cast<u32>(priority)) {
Thread* suggested = priority_queue.GetSuggestedFront(core_id);
while (suggested != nullptr) {
/* If the suggestion's priority is the same as ours, don't bother. */
if (suggested->GetPriority() >= best_thread->GetPriority()) {
break;
}
/* Check if the suggested thread is the top thread on its core. */
const s32 suggested_core = suggested->GetActiveCore();
if (Thread* top_on_suggested_core =
(suggested_core >= 0) ? priority_queue.GetScheduledFront(suggested_core)
: nullptr;
top_on_suggested_core != suggested) {
/* If we're allowed to do a migration, do one. */
/* NOTE: Unlike migrations in UpdateHighestPriorityThread, this moves the
* suggestion to the front of the queue. */
if (top_on_suggested_core == nullptr ||
top_on_suggested_core->GetPriority() >=
HighestCoreMigrationAllowedPriority) {
suggested->SetActiveCore(core_id);
priority_queue.ChangeCore(suggested_core, suggested, true);
IncrementScheduledCount(suggested);
break;
}
}
/* Get the next suggestion. */
suggested = priority_queue.GetSuggestedNext(core_id, suggested);
}
}
}
/* After a rotation, we need a scheduler update. */
SetSchedulerUpdateNeeded(kernel);
}
/*static*/ bool KScheduler::CanSchedule(KernelCore& kernel) {
return kernel.CurrentScheduler()->GetCurrentThread()->GetDisableDispatchCount() <= 1;
}
/*static*/ bool KScheduler::IsSchedulerUpdateNeeded(const KernelCore& kernel) {
return kernel.GlobalSchedulerContext().scheduler_update_needed.load(std::memory_order_acquire);
}
/*static*/ void KScheduler::SetSchedulerUpdateNeeded(KernelCore& kernel) {
kernel.GlobalSchedulerContext().scheduler_update_needed.store(true, std::memory_order_release);
}
/*static*/ void KScheduler::ClearSchedulerUpdateNeeded(KernelCore& kernel) {
kernel.GlobalSchedulerContext().scheduler_update_needed.store(false, std::memory_order_release);
}
/*static*/ void KScheduler::DisableScheduling(KernelCore& kernel) {
if (auto* scheduler = kernel.CurrentScheduler(); scheduler) {
ASSERT(scheduler->GetCurrentThread()->GetDisableDispatchCount() >= 0);
scheduler->GetCurrentThread()->DisableDispatch();
}
}
/*static*/ void KScheduler::EnableScheduling(KernelCore& kernel, u64 cores_needing_scheduling,
Core::EmuThreadHandle global_thread) {
if (auto* scheduler = kernel.CurrentScheduler(); scheduler) {
scheduler->GetCurrentThread()->EnableDispatch();
}
RescheduleCores(kernel, cores_needing_scheduling, global_thread);
}
/*static*/ u64 KScheduler::UpdateHighestPriorityThreads(KernelCore& kernel) {
if (IsSchedulerUpdateNeeded(kernel)) {
return UpdateHighestPriorityThreadsImpl(kernel);
} else {
return 0;
}
}
/*static*/ KSchedulerPriorityQueue& KScheduler::GetPriorityQueue(KernelCore& kernel) {
return kernel.GlobalSchedulerContext().priority_queue;
}
void KScheduler::YieldWithoutCoreMigration() {
auto& kernel = system.Kernel();
/* Validate preconditions. */
ASSERT(CanSchedule(kernel));
ASSERT(kernel.CurrentProcess() != nullptr);
/* Get the current thread and process. */
Thread& cur_thread = *GetCurrentThread();
Process& cur_process = *kernel.CurrentProcess();
/* If the thread's yield count matches, there's nothing for us to do. */
if (cur_thread.GetYieldScheduleCount() == cur_process.GetScheduledCount()) {
return;
}
/* Get a reference to the priority queue. */
auto& priority_queue = GetPriorityQueue(kernel);
/* Perform the yield. */
{
SchedulerLock lock(kernel);
const auto cur_state = cur_thread.scheduling_state;
if (cur_state == static_cast<u32>(ThreadSchedStatus::Runnable)) {
/* Put the current thread at the back of the queue. */
Thread* next_thread = priority_queue.MoveToScheduledBack(std::addressof(cur_thread));
IncrementScheduledCount(std::addressof(cur_thread));
/* If the next thread is different, we have an update to perform. */
if (next_thread != std::addressof(cur_thread)) {
SetSchedulerUpdateNeeded(kernel);
} else {
/* Otherwise, set the thread's yield count so that we won't waste work until the
* process is scheduled again. */
cur_thread.SetYieldScheduleCount(cur_process.GetScheduledCount());
}
}
}
}
void KScheduler::YieldWithCoreMigration() {
auto& kernel = system.Kernel();
/* Validate preconditions. */
ASSERT(CanSchedule(kernel));
ASSERT(kernel.CurrentProcess() != nullptr);
/* Get the current thread and process. */
Thread& cur_thread = *GetCurrentThread();
Process& cur_process = *kernel.CurrentProcess();
/* If the thread's yield count matches, there's nothing for us to do. */
if (cur_thread.GetYieldScheduleCount() == cur_process.GetScheduledCount()) {
return;
}
/* Get a reference to the priority queue. */
auto& priority_queue = GetPriorityQueue(kernel);
/* Perform the yield. */
{
SchedulerLock lock(kernel);
const auto cur_state = cur_thread.scheduling_state;
if (cur_state == static_cast<u32>(ThreadSchedStatus::Runnable)) {
/* Get the current active core. */
const s32 core_id = cur_thread.GetActiveCore();
/* Put the current thread at the back of the queue. */
Thread* next_thread = priority_queue.MoveToScheduledBack(std::addressof(cur_thread));
IncrementScheduledCount(std::addressof(cur_thread));
/* While we have a suggested thread, try to migrate it! */
bool recheck = false;
Thread* suggested = priority_queue.GetSuggestedFront(core_id);
while (suggested != nullptr) {
/* Check if the suggested thread is the thread running on its core. */
const s32 suggested_core = suggested->GetActiveCore();
if (Thread* running_on_suggested_core =
(suggested_core >= 0)
? kernel.Scheduler(suggested_core).state.highest_priority_thread
: nullptr;
running_on_suggested_core != suggested) {
/* If the current thread's priority is higher than our suggestion's we prefer
* the next thread to the suggestion. */
/* We also prefer the next thread when the current thread's priority is equal to
* the suggestions, but the next thread has been waiting longer. */
if ((suggested->GetPriority() > cur_thread.GetPriority()) ||
(suggested->GetPriority() == cur_thread.GetPriority() &&
next_thread != std::addressof(cur_thread) &&
next_thread->GetLastScheduledTick() < suggested->GetLastScheduledTick())) {
suggested = nullptr;
break;
}
/* If we're allowed to do a migration, do one. */
/* NOTE: Unlike migrations in UpdateHighestPriorityThread, this moves the
* suggestion to the front of the queue. */
if (running_on_suggested_core == nullptr ||
running_on_suggested_core->GetPriority() >=
HighestCoreMigrationAllowedPriority) {
suggested->SetActiveCore(core_id);
priority_queue.ChangeCore(suggested_core, suggested, true);
IncrementScheduledCount(suggested);
break;
} else {
/* We couldn't perform a migration, but we should check again on a future
* yield. */
recheck = true;
}
}
/* Get the next suggestion. */
suggested = priority_queue.GetSuggestedNext(core_id, suggested);
}
/* If we still have a suggestion or the next thread is different, we have an update to
* perform. */
if (suggested != nullptr || next_thread != std::addressof(cur_thread)) {
SetSchedulerUpdateNeeded(kernel);
} else if (!recheck) {
/* Otherwise if we don't need to re-check, set the thread's yield count so that we
* won't waste work until the process is scheduled again. */
cur_thread.SetYieldScheduleCount(cur_process.GetScheduledCount());
}
}
}
}
void KScheduler::YieldToAnyThread() {
auto& kernel = system.Kernel();
/* Validate preconditions. */
ASSERT(CanSchedule(kernel));
ASSERT(kernel.CurrentProcess() != nullptr);
/* Get the current thread and process. */
Thread& cur_thread = *GetCurrentThread();
Process& cur_process = *kernel.CurrentProcess();
/* If the thread's yield count matches, there's nothing for us to do. */
if (cur_thread.GetYieldScheduleCount() == cur_process.GetScheduledCount()) {
return;
}
/* Get a reference to the priority queue. */
auto& priority_queue = GetPriorityQueue(kernel);
/* Perform the yield. */
{
SchedulerLock lock(kernel);
const auto cur_state = cur_thread.scheduling_state;
if (cur_state == static_cast<u32>(ThreadSchedStatus::Runnable)) {
/* Get the current active core. */
const s32 core_id = cur_thread.GetActiveCore();
/* Migrate the current thread to core -1. */
cur_thread.SetActiveCore(-1);
priority_queue.ChangeCore(core_id, std::addressof(cur_thread));
IncrementScheduledCount(std::addressof(cur_thread));
/* If there's nothing scheduled, we can try to perform a migration. */
if (priority_queue.GetScheduledFront(core_id) == nullptr) {
/* While we have a suggested thread, try to migrate it! */
Thread* suggested = priority_queue.GetSuggestedFront(core_id);
while (suggested != nullptr) {
/* Check if the suggested thread is the top thread on its core. */
const s32 suggested_core = suggested->GetActiveCore();
if (Thread* top_on_suggested_core =
(suggested_core >= 0) ? priority_queue.GetScheduledFront(suggested_core)
: nullptr;
top_on_suggested_core != suggested) {
/* If we're allowed to do a migration, do one. */
if (top_on_suggested_core == nullptr ||
top_on_suggested_core->GetPriority() >=
HighestCoreMigrationAllowedPriority) {
suggested->SetActiveCore(core_id);
priority_queue.ChangeCore(suggested_core, suggested);
IncrementScheduledCount(suggested);
}
/* Regardless of whether we migrated, we had a candidate, so we're done. */
break;
}
/* Get the next suggestion. */
suggested = priority_queue.GetSuggestedNext(core_id, suggested);
}
/* If the suggestion is different from the current thread, we need to perform an
* update. */
if (suggested != std::addressof(cur_thread)) {
SetSchedulerUpdateNeeded(kernel);
} else {
/* Otherwise, set the thread's yield count so that we won't waste work until the
* process is scheduled again. */
cur_thread.SetYieldScheduleCount(cur_process.GetScheduledCount());
}
} else {
/* Otherwise, we have an update to perform. */
SetSchedulerUpdateNeeded(kernel);
}
}
}
}
KScheduler::KScheduler(Core::System& system, std::size_t core_id)
: system(system), core_id(core_id) {
switch_fiber = std::make_shared<Common::Fiber>(std::function<void(void*)>(OnSwitch), this);
this->state.needs_scheduling = true;
this->state.interrupt_task_thread_runnable = false;
this->state.should_count_idle = false;
this->state.idle_count = 0;
this->state.idle_thread_stack = nullptr;
this->state.highest_priority_thread = nullptr;
}
KScheduler::~KScheduler() = default;
Thread* KScheduler::GetCurrentThread() const {
if (current_thread) {
return current_thread;
}
return idle_thread;
}
u64 KScheduler::GetLastContextSwitchTicks() const {
return last_context_switch_time;
}
void KScheduler::RescheduleCurrentCore() {
ASSERT(GetCurrentThread()->GetDisableDispatchCount() == 1);
auto& phys_core = system.Kernel().PhysicalCore(core_id);
if (phys_core.IsInterrupted()) {
phys_core.ClearInterrupt();
}
guard.lock();
if (this->state.needs_scheduling) {
Schedule();
} else {
guard.unlock();
}
}
void KScheduler::OnThreadStart() {
SwitchContextStep2();
}
void KScheduler::Unload(Thread* thread) {
if (thread) {
thread->SetIsRunning(false);
if (thread->IsContinuousOnSVC() && !thread->IsHLEThread()) {
system.ArmInterface(core_id).ExceptionalExit();
thread->SetContinuousOnSVC(false);
}
if (!thread->IsHLEThread() && !thread->HasExited()) {
Core::ARM_Interface& cpu_core = system.ArmInterface(core_id);
cpu_core.SaveContext(thread->GetContext32());
cpu_core.SaveContext(thread->GetContext64());
// Save the TPIDR_EL0 system register in case it was modified.
thread->SetTPIDR_EL0(cpu_core.GetTPIDR_EL0());
cpu_core.ClearExclusiveState();
}
thread->context_guard.unlock();
}
}
void KScheduler::Reload(Thread* thread) {
if (thread) {
ASSERT_MSG(thread->GetSchedulingStatus() == ThreadSchedStatus::Runnable,
"Thread must be runnable.");
// Cancel any outstanding wakeup events for this thread
thread->SetIsRunning(true);
thread->SetWasRunning(false);
auto* const thread_owner_process = thread->GetOwnerProcess();
if (thread_owner_process != nullptr) {
system.Kernel().MakeCurrentProcess(thread_owner_process);
}
if (!thread->IsHLEThread()) {
Core::ARM_Interface& cpu_core = system.ArmInterface(core_id);
cpu_core.LoadContext(thread->GetContext32());
cpu_core.LoadContext(thread->GetContext64());
cpu_core.SetTlsAddress(thread->GetTLSAddress());
cpu_core.SetTPIDR_EL0(thread->GetTPIDR_EL0());
cpu_core.ClearExclusiveState();
}
}
}
void KScheduler::SwitchContextStep2() {
// Load context of new thread
Reload(current_thread);
RescheduleCurrentCore();
}
void KScheduler::ScheduleImpl() {
Thread* previous_thread = current_thread;
current_thread = state.highest_priority_thread;
this->state.needs_scheduling = false;
if (current_thread == previous_thread) {
guard.unlock();
return;
}
Process* const previous_process = system.Kernel().CurrentProcess();
UpdateLastContextSwitchTime(previous_thread, previous_process);
// Save context for previous thread
Unload(previous_thread);
std::shared_ptr<Common::Fiber>* old_context;
if (previous_thread != nullptr) {
old_context = &previous_thread->GetHostContext();
} else {
old_context = &idle_thread->GetHostContext();
}
guard.unlock();
Common::Fiber::YieldTo(*old_context, switch_fiber);
/// When a thread wakes up, the scheduler may have changed to other in another core.
auto& next_scheduler = *system.Kernel().CurrentScheduler();
next_scheduler.SwitchContextStep2();
}
void KScheduler::OnSwitch(void* this_scheduler) {
KScheduler* sched = static_cast<KScheduler*>(this_scheduler);
sched->SwitchToCurrent();
}
void KScheduler::SwitchToCurrent() {
while (true) {
{
std::scoped_lock lock{guard};
current_thread = state.highest_priority_thread;
this->state.needs_scheduling = false;
}
const auto is_switch_pending = [this] {
std::scoped_lock lock{guard};
return !!this->state.needs_scheduling;
};
do {
if (current_thread != nullptr && !current_thread->IsHLEThread()) {
current_thread->context_guard.lock();
if (!current_thread->IsRunnable()) {
current_thread->context_guard.unlock();
break;
}
if (static_cast<u32>(current_thread->GetProcessorID()) != core_id) {
current_thread->context_guard.unlock();
break;
}
}
std::shared_ptr<Common::Fiber>* next_context;
if (current_thread != nullptr) {
next_context = ¤t_thread->GetHostContext();
} else {
next_context = &idle_thread->GetHostContext();
}
Common::Fiber::YieldTo(switch_fiber, *next_context);
} while (!is_switch_pending());
}
}
void KScheduler::UpdateLastContextSwitchTime(Thread* thread, Process* process) {
const u64 prev_switch_ticks = last_context_switch_time;
const u64 most_recent_switch_ticks = system.CoreTiming().GetCPUTicks();
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 KScheduler::Initialize() {
std::string name = "Idle Thread Id:" + std::to_string(core_id);
std::function<void(void*)> init_func = Core::CpuManager::GetIdleThreadStartFunc();
void* init_func_parameter = system.GetCpuManager().GetStartFuncParamater();
ThreadType type = static_cast<ThreadType>(THREADTYPE_KERNEL | THREADTYPE_HLE | THREADTYPE_IDLE);
auto thread_res = Thread::Create(system, type, name, 0, 64, 0, static_cast<u32>(core_id), 0,
nullptr, std::move(init_func), init_func_parameter);
idle_thread = thread_res.Unwrap().get();
{
KScopedSchedulerLock lock{system.Kernel()};
idle_thread->SetStatus(ThreadStatus::Ready);
}
}
SchedulerLock::SchedulerLock(KernelCore& kernel) : kernel{kernel} {
kernel.GlobalSchedulerContext().Lock();
}
SchedulerLock::~SchedulerLock() {
kernel.GlobalSchedulerContext().Unlock();
}
SchedulerLockAndSleep::SchedulerLockAndSleep(KernelCore& kernel, Handle& event_handle,
Thread* time_task, s64 nanoseconds)
: SchedulerLock{kernel}, event_handle{event_handle}, time_task{time_task}, nanoseconds{
nanoseconds} {
event_handle = InvalidHandle;
}
SchedulerLockAndSleep::~SchedulerLockAndSleep() {
if (sleep_cancelled) {
return;
}
auto& time_manager = kernel.TimeManager();
time_manager.ScheduleTimeEvent(event_handle, time_task, nanoseconds);
}
void SchedulerLockAndSleep::Release() {
if (sleep_cancelled) {
return;
}
auto& time_manager = kernel.TimeManager();
time_manager.ScheduleTimeEvent(event_handle, time_task, nanoseconds);
sleep_cancelled = true;
}
} // namespace Kernel
