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kern: kill the interrupt task manager thread

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This commit is contained in:
Michael Scire 2021-09-17 16:12:01 -07:00 committed by SciresM
parent 29cc3d1c09
commit cb28150912
9 changed files with 112 additions and 140 deletions
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4
libraries/libmesosphere/include/mesosphere/arch/arm64/kern_assembly_offsets.h
View file

@ -157,6 +157,8 @@
/* ams::kern::KScheduler (::SchedulingState), https://github.com/Atmosphere-NX/Atmosphere/blob/master/libraries/libmesosphere/include/mesosphere/kern_k_scheduler.hpp */
/* NOTE: Due to constraints on ldarb relative offsets, KSCHEDULER_NEEDS_SCHEDULING cannot trivially be changed, and will require assembly edits. */
#define KSCHEDULER_NEEDS_SCHEDULING 0x00
#define KSCHEDULER_INTERRUPT_TASK_THREAD_RUNNABLE 0x01
#define KSCHEDULER_INTERRUPT_TASK_RUNNABLE 0x01
#define KSCHEDULER_HIGHEST_PRIORITY_THREAD 0x10
#define KSCHEDULER_IDLE_THREAD_STACK 0x18
#define KSCHEDULER_PREVIOUS_THREAD 0x20
#define KSCHEDULER_INTERRUPT_TASK_MANAGER 0x28

19
libraries/libmesosphere/include/mesosphere/kern_k_interrupt_task_manager.hpp
View file

@ -27,28 +27,25 @@ namespace ams::kern {
KInterruptTask *m_head;
KInterruptTask *m_tail;
public:
constexpr TaskQueue() : m_head(nullptr), m_tail(nullptr) { /* ... */ }
constexpr ALWAYS_INLINE TaskQueue() : m_head(nullptr), m_tail(nullptr) { /* ... */ }
constexpr KInterruptTask *GetHead() { return m_head; }
constexpr bool IsEmpty() const { return m_head == nullptr; }
constexpr void Clear() { m_head = nullptr; m_tail = nullptr; }
constexpr ALWAYS_INLINE KInterruptTask *GetHead() { return m_head; }
constexpr ALWAYS_INLINE bool IsEmpty() const { return m_head == nullptr; }
constexpr ALWAYS_INLINE void Clear() { m_head = nullptr; m_tail = nullptr; }
void Enqueue(KInterruptTask *task);
void Dequeue();
};
private:
TaskQueue m_task_queue;
KThread *m_thread;
private:
static void ThreadFunction(uintptr_t arg);
void ThreadFunctionImpl();
s64 m_cpu_time;
public:
constexpr KInterruptTaskManager() : m_task_queue(), m_thread(nullptr) { /* ... */ }
constexpr KInterruptTaskManager() : m_task_queue(), m_cpu_time(0) { /* ... */ }
constexpr KThread *GetThread() const { return m_thread; }
constexpr ALWAYS_INLINE s64 GetCpuTime() const { return m_cpu_time; }
NOINLINE void Initialize();
void EnqueueTask(KInterruptTask *task);
void DoTasks();
};
}

46
libraries/libmesosphere/include/mesosphere/kern_k_scheduler.hpp
View file

@ -17,6 +17,7 @@
#include <mesosphere/kern_select_cpu.hpp>
#include <mesosphere/kern_k_thread.hpp>
#include <mesosphere/kern_k_priority_queue.hpp>
#include <mesosphere/kern_k_interrupt_task_manager.hpp>
#include <mesosphere/kern_k_scheduler_lock.hpp>
namespace ams::kern {
@ -39,11 +40,13 @@ namespace ams::kern {
struct SchedulingState {
std::atomic<u8> needs_scheduling;
bool interrupt_task_thread_runnable;
bool interrupt_task_runnable;
bool should_count_idle;
u64 idle_count;
KThread *highest_priority_thread;
void *idle_thread_stack;
KThread *prev_thread;
KInterruptTaskManager *interrupt_task_manager;
};
private:
friend class KScopedSchedulerLock;
@ -53,27 +56,28 @@ namespace ams::kern {
SchedulingState m_state;
bool m_is_active;
s32 m_core_id;
KThread *m_prev_thread;
s64 m_last_context_switch_time;
KThread *m_idle_thread;
std::atomic<KThread *> m_current_thread;
public:
constexpr KScheduler()
: m_state(), m_is_active(false), m_core_id(0), m_prev_thread(nullptr), m_last_context_switch_time(0), m_idle_thread(nullptr), m_current_thread(nullptr)
: m_state(), m_is_active(false), m_core_id(0), m_last_context_switch_time(0), m_idle_thread(nullptr), m_current_thread(nullptr)
{
m_state.needs_scheduling = true;
m_state.interrupt_task_thread_runnable = false;
m_state.interrupt_task_runnable = false;
m_state.should_count_idle = false;
m_state.idle_count = 0;
m_state.idle_thread_stack = nullptr;
m_state.highest_priority_thread = nullptr;
m_state.prev_thread = nullptr;
m_state.interrupt_task_manager = nullptr;
}
NOINLINE void Initialize(KThread *idle_thread);
NOINLINE void Activate();
ALWAYS_INLINE void SetInterruptTaskRunnable() {
m_state.interrupt_task_thread_runnable = true;
m_state.interrupt_task_runnable = true;
m_state.needs_scheduling = true;
}
@ -94,7 +98,7 @@ namespace ams::kern {
}
ALWAYS_INLINE KThread *GetPreviousThread() const {
return m_prev_thread;
return m_state.prev_thread;
}
ALWAYS_INLINE KThread *GetSchedulerCurrentThread() const {
@ -108,8 +112,6 @@ namespace ams::kern {
/* Static private API. */
static ALWAYS_INLINE KSchedulerPriorityQueue &GetPriorityQueue() { return s_priority_queue; }
static NOINLINE u64 UpdateHighestPriorityThreadsImpl();
static NOINLINE void InterruptTaskThreadToRunnable();
public:
/* Static public API. */
static ALWAYS_INLINE bool CanSchedule() { return GetCurrentThread().GetDisableDispatchCount() == 0; }
@ -124,13 +126,14 @@ namespace ams::kern {
GetCurrentThread().DisableDispatch();
}
static NOINLINE void EnableScheduling(u64 cores_needing_scheduling) {
static ALWAYS_INLINE void EnableScheduling(u64 cores_needing_scheduling) {
MESOSPHERE_ASSERT(GetCurrentThread().GetDisableDispatchCount() >= 1);
GetCurrentScheduler().RescheduleOtherCores(cores_needing_scheduling);
if (GetCurrentThread().GetDisableDispatchCount() > 1) {
GetCurrentThread().EnableDispatch();
} else {
GetCurrentScheduler().RescheduleOtherCores(cores_needing_scheduling);
GetCurrentScheduler().RescheduleCurrentCore();
}
}
@ -176,15 +179,24 @@ namespace ams::kern {
ALWAYS_INLINE void RescheduleCurrentCore() {
MESOSPHERE_ASSERT(GetCurrentThread().GetDisableDispatchCount() == 1);
{
/* Disable interrupts, and then context switch. */
KScopedInterruptDisable intr_disable;
ON_SCOPE_EXIT { GetCurrentThread().EnableDispatch(); };
GetCurrentThread().EnableDispatch();
if (m_state.needs_scheduling.load()) {
Schedule();
/* Disable interrupts, and then check again if rescheduling is needed. */
KScopedInterruptDisable intr_disable;
GetCurrentScheduler().RescheduleCurrentCoreImpl();
}
}
ALWAYS_INLINE void RescheduleCurrentCoreImpl() {
/* Check that scheduling is needed. */
if (AMS_LIKELY(m_state.needs_scheduling.load())) {
GetCurrentThread().DisableDispatch();
this->Schedule();
GetCurrentThread().EnableDispatch();
}
}
NOINLINE u64 UpdateHighestPriorityThread(KThread *thread);
@ -200,9 +212,11 @@ namespace ams::kern {
consteval bool KScheduler::ValidateAssemblyOffsets() {
static_assert(__builtin_offsetof(KScheduler, m_state.needs_scheduling) == KSCHEDULER_NEEDS_SCHEDULING);
static_assert(__builtin_offsetof(KScheduler, m_state.interrupt_task_thread_runnable) == KSCHEDULER_INTERRUPT_TASK_THREAD_RUNNABLE);
static_assert(__builtin_offsetof(KScheduler, m_state.interrupt_task_runnable) == KSCHEDULER_INTERRUPT_TASK_RUNNABLE);
static_assert(__builtin_offsetof(KScheduler, m_state.highest_priority_thread) == KSCHEDULER_HIGHEST_PRIORITY_THREAD);
static_assert(__builtin_offsetof(KScheduler, m_state.idle_thread_stack) == KSCHEDULER_IDLE_THREAD_STACK);
static_assert(__builtin_offsetof(KScheduler, m_state.prev_thread) == KSCHEDULER_PREVIOUS_THREAD);
static_assert(__builtin_offsetof(KScheduler, m_state.interrupt_task_manager) == KSCHEDULER_INTERRUPT_TASK_MANAGER);
return true;
}

4
libraries/libmesosphere/include/mesosphere/kern_k_scheduler_lock.hpp
View file

@ -45,7 +45,7 @@ namespace ams::kern {
return m_owner_thread == GetCurrentThreadPointer();
}
void Lock() {
NOINLINE void Lock() {
MESOSPHERE_ASSERT_THIS();
if (this->IsLockedByCurrentThread()) {
@ -67,7 +67,7 @@ namespace ams::kern {
}
}
void Unlock() {
NOINLINE void Unlock() {
MESOSPHERE_ASSERT_THIS();
MESOSPHERE_ASSERT(this->IsLockedByCurrentThread());
MESOSPHERE_ASSERT(m_lock_count > 0);

64
libraries/libmesosphere/source/kern_k_interrupt_task_manager.cpp
View file

@ -59,50 +59,6 @@ namespace ams::kern {
#endif
}
void KInterruptTaskManager::ThreadFunction(uintptr_t arg) {
reinterpret_cast<KInterruptTaskManager *>(arg)->ThreadFunctionImpl();
}
void KInterruptTaskManager::ThreadFunctionImpl() {
MESOSPHERE_ASSERT_THIS();
while (true) {
/* Get a task. */
KInterruptTask *task = nullptr;
{
KScopedInterruptDisable di;
task = m_task_queue.GetHead();
if (task == nullptr) {
m_thread->SetState(KThread::ThreadState_Waiting);
continue;
}
m_task_queue.Dequeue();
}
/* Do the task. */
task->DoTask();
/* Destroy any objects we may need to close. */
m_thread->DestroyClosedObjects();
}
}
void KInterruptTaskManager::Initialize() {
/* Reserve a thread from the system limit. */
MESOSPHERE_ABORT_UNLESS(Kernel::GetSystemResourceLimit().Reserve(ams::svc::LimitableResource_ThreadCountMax, 1));
/* Create and initialize the thread. */
m_thread = KThread::Create();
MESOSPHERE_ABORT_UNLESS(m_thread != nullptr);
MESOSPHERE_R_ABORT_UNLESS(KThread::InitializeHighPriorityThread(m_thread, ThreadFunction, reinterpret_cast<uintptr_t>(this)));
KThread::Register(m_thread);
/* Run the thread. */
m_thread->Run();
}
void KInterruptTaskManager::EnqueueTask(KInterruptTask *task) {
MESOSPHERE_ASSERT(!KInterruptManager::AreInterruptsEnabled());
@ -111,4 +67,24 @@ namespace ams::kern {
Kernel::GetScheduler().SetInterruptTaskRunnable();
}
void KInterruptTaskManager::DoTasks() {
/* Execute pending tasks. */
const s64 start_time = KHardwareTimer::GetTick();
for (KInterruptTask *task = m_task_queue.GetHead(); task != nullptr; task = m_task_queue.GetHead()) {
/* Dequeue the task. */
m_task_queue.Dequeue();
/* Do the task with interrupts temporarily enabled. */
{
KScopedInterruptEnable ei;
task->DoTask();
}
}
const s64 end_time = KHardwareTimer::GetTick();
/* Increment the time we've spent executing. */
m_cpu_time += end_time - start_time;
}
}

25
libraries/libmesosphere/source/kern_k_scheduler.cpp
View file

@ -55,10 +55,11 @@ namespace ams::kern {
}
void KScheduler::Initialize(KThread *idle_thread) {
/* Set core ID and idle thread. */
/* Set core ID/idle thread/interrupt task manager. */
m_core_id = GetCurrentCoreId();
m_idle_thread = idle_thread;
m_state.idle_thread_stack = m_idle_thread->GetStackTop();
m_state.interrupt_task_manager = std::addressof(Kernel::GetInterruptTaskManager());
/* Insert the main thread into the priority queue. */
{
@ -212,19 +213,9 @@ namespace ams::kern {
return cores_needing_scheduling;
}
void KScheduler::InterruptTaskThreadToRunnable() {
MESOSPHERE_ASSERT(GetCurrentThread().GetDisableDispatchCount() == 1);
KThread *task_thread = Kernel::GetInterruptTaskManager().GetThread();
{
KScopedSchedulerLock sl;
task_thread->SetState(KThread::ThreadState_Runnable);
}
}
void KScheduler::SwitchThread(KThread *next_thread) {
KProcess *cur_process = GetCurrentProcessPointer();
KThread *cur_thread = GetCurrentThreadPointer();
KProcess * const cur_process = GetCurrentProcessPointer();
KThread * const cur_thread = GetCurrentThreadPointer();
/* We never want to schedule a null thread, so use the idle thread if we don't have a next. */
if (next_thread == nullptr) {
@ -257,12 +248,10 @@ namespace ams::kern {
if (cur_process != nullptr) {
/* NOTE: Combining this into AMS_LIKELY(!... && ...) triggers an internal compiler error: Segmentation fault in GCC 9.2.0. */
if (AMS_LIKELY(!cur_thread->IsTerminationRequested()) && AMS_LIKELY(cur_thread->GetActiveCore() == m_core_id)) {
m_prev_thread = cur_thread;
m_state.prev_thread = cur_thread;
} else {
m_prev_thread = nullptr;
m_state.prev_thread = nullptr;
}
} else if (cur_thread == m_idle_thread) {
m_prev_thread = nullptr;
}
MESOSPHERE_KTRACE_THREAD_SWITCH(next_thread);
@ -284,7 +273,7 @@ namespace ams::kern {
MESOSPHERE_ASSERT(IsSchedulerLockedByCurrentThread());
for (size_t i = 0; i < cpu::NumCores; ++i) {
/* Get an atomic reference to the core scheduler's previous thread. */
std::atomic_ref<KThread *> prev_thread(Kernel::GetScheduler(static_cast<s32>(i)).m_prev_thread);
std::atomic_ref<KThread *> prev_thread(Kernel::GetScheduler(static_cast<s32>(i)).m_state.prev_thread);
static_assert(std::atomic_ref<KThread *>::is_always_lock_free);
/* Atomically clear the previous thread if it's our target. */

1
libraries/libmesosphere/source/kern_main.cpp
View file

@ -99,7 +99,6 @@ namespace ams::kern {
DoOnEachCoreInOrder(core_id, [=]() ALWAYS_INLINE_LAMBDA {
KThread::Register(std::addressof(Kernel::GetMainThread(core_id)));
KThread::Register(std::addressof(Kernel::GetIdleThread(core_id)));
Kernel::GetInterruptTaskManager().Initialize();
});
/* Activate the scheduler and enable interrupts. */

2
libraries/libmesosphere/source/svc/kern_svc_info.cpp
View file

@ -189,7 +189,7 @@ namespace ams::kern::svc {
R_UNLESS(core_valid, svc::ResultInvalidCombination());
/* Get the idle tick count. */
*out = Kernel::GetScheduler().GetIdleThread()->GetCpuTime();
*out = Kernel::GetScheduler().GetIdleThread()->GetCpuTime() - Kernel::GetInterruptTaskManager().GetCpuTime();
}
break;
case ams::svc::InfoType_RandomEntropy:

55
mesosphere/kernel/source/arch/arm64/kern_k_scheduler_asm.s
View file

@ -112,29 +112,16 @@ _ZN3ams4kern10KScheduler12ScheduleImplEv:
/* KScheduler layout has state at +0x0, this is guaranteed statically by assembly offsets. */
mov x1, x0
/* First thing we want to do is check whether the interrupt task thread is runnable. */
ldrb w3, [x1, #(KSCHEDULER_INTERRUPT_TASK_THREAD_RUNNABLE)]
cbz w3, 0f
/* If it is, we want to call KScheduler::InterruptTaskThreadToRunnable() to change its state to runnable. */
stp x0, x1, [sp, #-16]!
stp x30, xzr, [sp, #-16]!
bl _ZN3ams4kern10KScheduler29InterruptTaskThreadToRunnableEv
ldp x30, xzr, [sp], 16
ldp x0, x1, [sp], 16
/* Clear the interrupt task thread as runnable. */
strb wzr, [x1, #(KSCHEDULER_INTERRUPT_TASK_THREAD_RUNNABLE)]
0: /* Interrupt task thread runnable checked. */
/* Now we want to check if there's any scheduling to do. */
/* First, clear the need's scheduling bool (and dmb ish after, as it's an atomic). */
/* TODO: Should this be a stlrb? Nintendo does not do one. */
strb wzr, [x1]
dmb ish
/* Check if the highest priority thread is the same as the current thread. */
/* Check whether there are runnable interrupt tasks. */
ldrb w8, [x1, #(KSCHEDULER_INTERRUPT_TASK_RUNNABLE)]
cbnz w8, 0f
/* If it isn't, we want to check if the highest priority thread is the same as the current thread. */
ldr x7, [x1, #(KSCHEDULER_HIGHEST_PRIORITY_THREAD)]
cmp x7, x18
b.ne 1f
@ -142,6 +129,10 @@ _ZN3ams4kern10KScheduler12ScheduleImplEv:
/* If they're the same, then we can just return as there's nothing to do. */
ret
0: /* The interrupt task thread is runnable. */
/* We want to switch to the interrupt task/idle thread. */
mov x7, #0
1: /* The highest priority thread is not the same as the current thread. */
/* Get a reference to the current thread's stack parameters. */
add x2, sp, #0x1000
@ -271,12 +262,19 @@ _ZN3ams4kern10KScheduler12ScheduleImplEv:
/* Call ams::kern::KScheduler::SwitchThread(ams::kern::KThread *) */
bl _ZN3ams4kern10KScheduler12SwitchThreadEPNS0_7KThreadE
12: /* We've switched to the idle thread, so we want to loop until we schedule a non-idle thread. */
/* Check if we need scheduling. */
ldarb w3, [x20] // ldarb w3, [x20, #(KSCHEDULER_NEEDS_SCHEDULING)]
12: /* We've switched to the idle thread, so we want to process interrupt tasks until we schedule a non-idle thread. */
/* Check whether there are runnable interrupt tasks. */
ldrb w3, [x20, #(KSCHEDULER_INTERRUPT_TASK_RUNNABLE)]
cbnz w3, 13f
/* If we don't, wait for an interrupt and check again. */
/* Check if we need scheduling. */
ldarb w3, [x20] // ldarb w3, [x20, #(KSCHEDULER_NEEDS_SCHEDULING)]
cbnz w3, 4b
/* Clear the previous thread. */
str xzr, [x20, #(KSCHEDULER_PREVIOUS_THREAD)]
/* Wait for an interrupt and check again. */
wfi
msr daifclr, #2
@ -284,16 +282,13 @@ _ZN3ams4kern10KScheduler12ScheduleImplEv:
b 12b
13: /* We need scheduling again! */
/* Check whether the interrupt task thread needs to be set runnable. */
ldrb w3, [x20, #(KSCHEDULER_INTERRUPT_TASK_THREAD_RUNNABLE)]
cbz w3, 4b
/* It does, so do so. We're using the idle thread stack so no register state preserve needed. */
bl _ZN3ams4kern10KScheduler29InterruptTaskThreadToRunnableEv
13: /* We have interrupt tasks to execute! */
/* Execute any pending interrupt tasks. */
ldr x0, [x20, #(KSCHEDULER_INTERRUPT_TASK_MANAGER)]
bl _ZN3ams4kern21KInterruptTaskManager7DoTasksEv
/* Clear the interrupt task thread as runnable. */
strb wzr, [x20, #(KSCHEDULER_INTERRUPT_TASK_THREAD_RUNNABLE)]
strb wzr, [x20, #(KSCHEDULER_INTERRUPT_TASK_RUNNABLE)]
/* Retry the scheduling loop. */
b 4b