yuzu/src/core/hle/kernel/scheduler.cpp
Lioncash fad20213e6 kernel/scheduler: Pass in system instance in constructor
Avoids directly relying on the global system instance and instead makes
an arbitrary system instance an explicit dependency on construction.

This also allows removing dependencies on some global accessor functions
as well.
2019-03-04 17:01:37 -05:00

249 lines
8.3 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/core_cpu.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::System& system, Core::ARM_Interface& cpu_core)
: cpu_core{cpu_core}, system{system} {}
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 = system.Kernel().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) {
system.Kernel().MakeCurrentProcess(thread_owner_process);
SetCurrentPageTable(&thread_owner_process->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 = system.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);
}
Thread* Scheduler::GetNextSuggestedThread(u32 core, u32 maximum_priority) const {
std::lock_guard<std::mutex> lock(scheduler_mutex);
const u32 mask = 1U << core;
return ready_queue.get_first_filter([mask, maximum_priority](Thread const* thread) {
return (thread->GetAffinityMask() & mask) != 0 && thread->GetPriority() < maximum_priority;
});
}
void Scheduler::YieldWithoutLoadBalancing(Thread* thread) {
ASSERT(thread != nullptr);
// Avoid yielding if the thread isn't even running.
ASSERT(thread->GetStatus() == ThreadStatus::Running);
// Sanity check that the priority is valid
ASSERT(thread->GetPriority() < THREADPRIO_COUNT);
// Yield this thread -- sleep for zero time and force reschedule to different thread
WaitCurrentThread_Sleep();
GetCurrentThread()->WakeAfterDelay(0);
}
void Scheduler::YieldWithLoadBalancing(Thread* thread) {
ASSERT(thread != nullptr);
const auto priority = thread->GetPriority();
const auto core = static_cast<u32>(thread->GetProcessorID());
// Avoid yielding if the thread isn't even running.
ASSERT(thread->GetStatus() == ThreadStatus::Running);
// Sanity check that the priority is valid
ASSERT(priority < THREADPRIO_COUNT);
// Sleep for zero time to be able to force reschedule to different thread
WaitCurrentThread_Sleep();
GetCurrentThread()->WakeAfterDelay(0);
Thread* suggested_thread = nullptr;
// Search through all of the cpu cores (except this one) for a suggested thread.
// Take the first non-nullptr one
for (unsigned cur_core = 0; cur_core < Core::NUM_CPU_CORES; ++cur_core) {
const auto res =
system.CpuCore(cur_core).Scheduler().GetNextSuggestedThread(core, priority);
// If scheduler provides a suggested thread
if (res != nullptr) {
// And its better than the current suggested thread (or is the first valid one)
if (suggested_thread == nullptr ||
suggested_thread->GetPriority() > res->GetPriority()) {
suggested_thread = res;
}
}
}
// If a suggested thread was found, queue that for this core
if (suggested_thread != nullptr)
suggested_thread->ChangeCore(core, suggested_thread->GetAffinityMask());
}
void Scheduler::YieldAndWaitForLoadBalancing(Thread* thread) {
UNIMPLEMENTED_MSG("Wait for load balancing thread yield type is not implemented!");
}
} // namespace Kernel