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Implement PI-Mutexes + Optimize InsertThread

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◱ PixelyIon 2020-12-16 00:24:08 +05:30 committed by ◱ Mark
parent 7ba7cd2394
commit 7079f11add
7 changed files with 215 additions and 130 deletions
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66
app/src/main/cpp/skyline/kernel/scheduler.cpp
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@ -30,7 +30,6 @@ namespace skyline::kernel {
if (!currentCore->queue.empty() && thread->affinityMask.count() != 1) { if (!currentCore->queue.empty() && thread->affinityMask.count() != 1) {
// Select core where the current thread will be scheduled the earliest based off average timeslice durations for resident threads // Select core where the current thread will be scheduled the earliest based off average timeslice durations for resident threads
// There's a preference for the current core as migration isn't free // There's a preference for the current core as migration isn't free
size_t minTimeslice{}; size_t minTimeslice{};
CoreContext *optimalCore{}; CoreContext *optimalCore{};
for (auto &candidateCore : cores) { for (auto &candidateCore : cores) {
@ -63,7 +62,7 @@ namespace skyline::kernel {
if (optimalCore != currentCore) { if (optimalCore != currentCore) {
std::unique_lock coreLock(currentCore->mutex); std::unique_lock coreLock(currentCore->mutex);
currentCore->queue.erase(std::remove(currentCore->queue.begin(), currentCore->queue.end(), thread), currentCore->queue.end()); currentCore->queue.erase(std::remove(currentCore->queue.begin(), currentCore->queue.end(), thread), currentCore->queue.end());
currentCore->mutateCondition.notify_all(); currentCore->frontCondition.notify_all();
thread->coreId = optimalCore->id; thread->coreId = optimalCore->id;
@ -80,11 +79,14 @@ namespace skyline::kernel {
return *currentCore; return *currentCore;
} }
void Scheduler::InsertThread(bool loadBalance) { void Scheduler::InsertThread(const std::shared_ptr<type::KThread> &thread, bool loadBalance) {
auto &thread{state.thread};
auto &core{loadBalance ? LoadBalance() : cores.at(thread->coreId)}; auto &core{loadBalance ? LoadBalance() : cores.at(thread->coreId)};
thread_local bool signalHandlerSetup{};
if (!signalHandlerSetup) {
signal::SetSignalHandler({YieldSignal}, SignalHandler); signal::SetSignalHandler({YieldSignal}, SignalHandler);
signalHandlerSetup = true;
}
if (!thread->preemptionTimer) { if (!thread->preemptionTimer) {
struct sigevent event{ struct sigevent event{
@ -92,19 +94,34 @@ namespace skyline::kernel {
.sigev_notify = SIGEV_THREAD_ID, .sigev_notify = SIGEV_THREAD_ID,
.sigev_notify_thread_id = gettid(), .sigev_notify_thread_id = gettid(),
}; };
timer_create(CLOCK_THREAD_CPUTIME_ID, &event, &*thread->preemptionTimer); timer_t timer;
if (timer_create(CLOCK_THREAD_CPUTIME_ID, &event, &timer))
throw exception("timer_create has failed with '{}'", strerror(errno));
thread->preemptionTimer.emplace(timer);
} }
std::unique_lock lock(core.mutex); std::unique_lock lock(core.mutex);
auto nextThread{std::find_if(core.queue.begin(), core.queue.end(), [&](const std::shared_ptr<type::KThread> &it) { return it->priority > thread->priority; })}; auto nextThread{std::upper_bound(core.queue.begin(), core.queue.end(), thread->priority.load(), type::KThread::IsHigherPriority)};
if (nextThread == core.queue.begin() && nextThread != core.queue.end()) { if (nextThread == core.queue.begin()) {
if (nextThread != core.queue.end()) {
// If the inserted thread has a higher priority than the currently running thread (and the queue isn't empty) // If the inserted thread has a higher priority than the currently running thread (and the queue isn't empty)
core.queue.front()->SendSignal(YieldSignal); // We need to interrupt the currently scheduled thread and put this thread at the front instead
core.queue.insert(std::next(core.queue.begin()), thread); core.queue.insert(std::next(core.queue.begin()), thread);
if (state.thread != core.queue.front())
core.queue.front()->SendSignal(YieldSignal);
else
YieldPending = true;
} else {
core.queue.push_front(thread);
}
if (thread != state.thread) {
lock.unlock(); // We should unlock this prior to waking all threads to not cause contention on the core lock
core.frontCondition.notify_all(); // We only want to trigger the conditional variable if the current thread isn't inserting itself
}
} else { } else {
core.queue.insert(nextThread, thread); core.queue.insert(nextThread, thread);
core.mutateCondition.notify_all(); // We only want to trigger the conditional variable if the current thread isn't going to be scheduled next
} }
thread->needsReorder = true; // We need to reorder the thread from back to align it with other threads of it's priority and ensure strict ordering amongst priorities thread->needsReorder = true; // We need to reorder the thread from back to align it with other threads of it's priority and ensure strict ordering amongst priorities
} }
@ -115,13 +132,13 @@ namespace skyline::kernel {
std::shared_lock lock(core->mutex); std::shared_lock lock(core->mutex);
if (thread->affinityMask.count() > 1) { if (thread->affinityMask.count() > 1) {
std::chrono::milliseconds loadBalanceThreshold{PreemptiveTimeslice * 2}; //!< The amount of time that needs to pass unscheduled for a thread to attempt load balancing std::chrono::milliseconds loadBalanceThreshold{PreemptiveTimeslice * 2}; //!< The amount of time that needs to pass unscheduled for a thread to attempt load balancing
while (!core->mutateCondition.wait_for(lock, loadBalanceThreshold, [&]() { return core->queue.front() == thread; })) { while (!core->frontCondition.wait_for(lock, loadBalanceThreshold, [&]() { return !core->queue.empty() && core->queue.front() == thread; })) {
lock.unlock(); lock.unlock();
LoadBalance(); LoadBalance();
if (thread->coreId == core->id) { if (thread->coreId == core->id) {
lock.lock(); lock.lock();
} else { } else {
InsertThread(false); InsertThread(state.thread, false);
core = &cores.at(thread->coreId); core = &cores.at(thread->coreId);
lock = std::shared_lock(core->mutex); lock = std::shared_lock(core->mutex);
} }
@ -129,7 +146,7 @@ namespace skyline::kernel {
loadBalanceThreshold *= 2; // We double the duration required for future load balancing for this invocation to minimize pointless load balancing loadBalanceThreshold *= 2; // We double the duration required for future load balancing for this invocation to minimize pointless load balancing
} }
} else { } else {
core->mutateCondition.wait(lock, [&]() { return core->queue.front() == thread; }); core->frontCondition.wait(lock, [&]() { return !core->queue.empty() && core->queue.front() == thread; });
} }
if (thread->priority == core->preemptionPriority) { if (thread->priority == core->preemptionPriority) {
@ -160,14 +177,15 @@ namespace skyline::kernel {
auto foldingPoint{std::find_if(std::next(core.queue.begin()), core.queue.end(), [&](const std::shared_ptr<type::KThread> &it) { auto foldingPoint{std::find_if(std::next(core.queue.begin()), core.queue.end(), [&](const std::shared_ptr<type::KThread> &it) {
return lastPriority > it->priority ? true : lastPriority = it->priority, false; return lastPriority > it->priority ? true : lastPriority = it->priority, false;
})}; })};
core.queue.insert(std::find_if(foldingPoint, core.queue.end(), [&](const std::shared_ptr<type::KThread> &it) { return it->priority > thread->priority; }), thread); core.queue.insert(std::upper_bound(foldingPoint, core.queue.end(), thread->priority.load(), type::KThread::IsHigherPriority), thread);
thread->needsReorder = false; thread->needsReorder = false;
} else { } else {
core.queue.push_back(thread); core.queue.push_back(thread);
thread->needsReorder = false; thread->needsReorder = false;
} }
core.mutateCondition.notify_all(); lock.unlock();
core.frontCondition.notify_all();
if (cooperative && thread->isPreempted) { if (cooperative && thread->isPreempted) {
// If a preemptive thread did a cooperative yield then we need to disarm the preemptive timer // If a preemptive thread did a cooperative yield then we need to disarm the preemptive timer
@ -178,7 +196,7 @@ namespace skyline::kernel {
} }
} }
void Scheduler::UpdatePriority(const std::shared_ptr<type::KThread>& thread) { void Scheduler::UpdatePriority(const std::shared_ptr<type::KThread> &thread) {
std::lock_guard migrationLock(thread->coreMigrationMutex); std::lock_guard migrationLock(thread->coreMigrationMutex);
auto *core{&cores.at(thread->coreId)}; auto *core{&cores.at(thread->coreId)};
std::unique_lock coreLock(core->mutex); std::unique_lock coreLock(core->mutex);
@ -188,12 +206,18 @@ namespace skyline::kernel {
// If the thread isn't in the queue then the new priority will be handled automatically on insertion // If the thread isn't in the queue then the new priority will be handled automatically on insertion
return; return;
if (currentIt == core->queue.begin()) { if (currentIt == core->queue.begin()) {
// Alternatively, if it's currently running then we'd just want to update after it rotates // Alternatively, if it's currently running then we'd just want to reorder after it rotates
if (!thread->isPreempted && thread->priority == core->preemptionPriority) {
// If the thread needs to be preempted due to the new priority then arm it's preemption timer
struct itimerspec spec{.it_value = {.tv_nsec = std::chrono::duration_cast<std::chrono::nanoseconds>(PreemptiveTimeslice).count()}};
timer_settime(*thread->preemptionTimer, 0, &spec, nullptr);
thread->isPreempted = true;
}
thread->needsReorder = true; thread->needsReorder = true;
return; return;
} }
auto targetIt{std::find_if(core->queue.begin(), core->queue.end(), [&](const std::shared_ptr<type::KThread> &it) { return it->priority > thread->priority; })}; auto targetIt{std::upper_bound(core->queue.begin(), core->queue.end(), thread->priority.load(), type::KThread::IsHigherPriority)};
if (currentIt == targetIt) if (currentIt == targetIt)
// If this thread's position isn't affected by the priority change then we have nothing to do // If this thread's position isn't affected by the priority change then we have nothing to do
return; return;
@ -206,13 +230,12 @@ namespace skyline::kernel {
thread->isPreempted = false; thread->isPreempted = false;
} }
targetIt = std::find_if(core->queue.begin(), core->queue.end(), [&](const std::shared_ptr<type::KThread> &it) { return it->priority > thread->priority; }); // Iterator invalidation targetIt = std::upper_bound(core->queue.begin(), core->queue.end(), thread->priority.load(), type::KThread::IsHigherPriority); // Iterator invalidation
if (targetIt == core->queue.begin() && targetIt != core->queue.end()) { if (targetIt == core->queue.begin() && targetIt != core->queue.end()) {
core->queue.front()->SendSignal(YieldSignal);
core->queue.insert(std::next(core->queue.begin()), thread); core->queue.insert(std::next(core->queue.begin()), thread);
core->queue.front()->SendSignal(YieldSignal);
} else { } else {
core->queue.insert(targetIt, thread); core->queue.insert(targetIt, thread);
core->mutateCondition.notify_all();
} }
thread->needsReorder = true; thread->needsReorder = true;
} }
@ -221,8 +244,11 @@ namespace skyline::kernel {
auto &thread{state.thread}; auto &thread{state.thread};
auto &core{cores.at(thread->coreId)}; auto &core{cores.at(thread->coreId)};
{
std::unique_lock lock(core.mutex); std::unique_lock lock(core.mutex);
core.queue.erase(std::remove(core.queue.begin(), core.queue.end(), thread), core.queue.end()); core.queue.erase(std::remove(core.queue.begin(), core.queue.end(), thread), core.queue.end());
}
core.frontCondition.notify_all(); // We need to notify any threads in line to be scheduled
if (thread->isPreempted) { if (thread->isPreempted) {
struct itimerspec spec{}; struct itimerspec spec{};

7
app/src/main/cpp/skyline/kernel/scheduler.h
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@ -46,7 +46,7 @@ namespace skyline {
u8 id; u8 id;
u8 preemptionPriority; //!< The priority at which this core becomes preemptive as opposed to cooperative u8 preemptionPriority; //!< The priority at which this core becomes preemptive as opposed to cooperative
std::shared_mutex mutex; //!< Synchronizes all operations on the queue std::shared_mutex mutex; //!< Synchronizes all operations on the queue
std::condition_variable_any mutateCondition; //!< A conditional variable which is signalled on every mutation of the queue std::condition_variable_any frontCondition; //!< A conditional variable which is signalled when the front of the queue has changed
std::deque<std::shared_ptr<type::KThread>> queue; //!< A queue of threads which are running or to be run on this core std::deque<std::shared_ptr<type::KThread>> queue; //!< A queue of threads which are running or to be run on this core
CoreContext(u8 id, u8 preemptionPriority); CoreContext(u8 id, u8 preemptionPriority);
@ -74,10 +74,11 @@ namespace skyline {
CoreContext& LoadBalance(); CoreContext& LoadBalance();
/** /**
* @brief Inserts the calling thread into the scheduler queue at the appropriate location based on it's priority * @brief Inserts the specified thread into the scheduler queue at the appropriate location based on it's priority
* @param loadBalance If to load balance or use the thread's current core (KThread::coreId) * @param loadBalance If to load balance or use the thread's current core (KThread::coreId)
* @note It isn't supported to load balance if the supplied thread isn't the calling thread, it'll lead to UB
*/ */
void InsertThread(bool loadBalance = true); void InsertThread(const std::shared_ptr<type::KThread>& thread, bool loadBalance = true);
/** /**
* @brief Wait for the current thread to be scheduled on it's resident core * @brief Wait for the current thread to be scheduled on it's resident core

42
app/src/main/cpp/skyline/kernel/svc.cpp
View File

@ -276,7 +276,7 @@ namespace skyline::kernel::svc {
} }
void ExitThread(const DeviceState &state) { void ExitThread(const DeviceState &state) {
state.logger->Debug("svcExitThread: Exiting current thread: {}", state.thread->id); state.logger->Debug("svcExitThread: Exiting current thread");
std::longjmp(state.thread->originalCtx, true); std::longjmp(state.thread->originalCtx, true);
} }
@ -330,9 +330,11 @@ namespace skyline::kernel::svc {
} }
try { try {
auto thread{state.process->GetHandle<type::KThread>(handle)}; auto thread{state.process->GetHandle<type::KThread>(handle)};
state.logger->Debug("svcSetThreadPriority: Setting thread priority to {}", thread->id, priority); state.logger->Debug("svcSetThreadPriority: Setting thread priority to {}", priority);
if (thread->priority != priority) {
thread->priority = priority; thread->priority = priority;
state.scheduler->UpdatePriority(thread); state.scheduler->UpdatePriority(thread);
}
state.ctx->gpr.w0 = Result{}; state.ctx->gpr.w0 = Result{};
} catch (const std::out_of_range &) { } catch (const std::out_of_range &) {
state.logger->Warn("svcSetThreadPriority: 'handle' invalid: 0x{:X}", handle); state.logger->Warn("svcSetThreadPriority: 'handle' invalid: 0x{:X}", handle);
@ -346,7 +348,7 @@ namespace skyline::kernel::svc {
auto thread{state.process->GetHandle<type::KThread>(handle)}; auto thread{state.process->GetHandle<type::KThread>(handle)};
auto idealCore{thread->idealCore}; auto idealCore{thread->idealCore};
auto affinityMask{thread->affinityMask}; auto affinityMask{thread->affinityMask};
state.logger->Debug("svcGetThreadCoreMask: Writing thread #{}'s Ideal Core ({}) + Affinity Mask ({})", thread->id, idealCore, affinityMask); state.logger->Debug("svcGetThreadCoreMask: Setting Ideal Core ({}) + Affinity Mask ({})", idealCore, affinityMask);
state.ctx->gpr.x2 = affinityMask.to_ullong(); state.ctx->gpr.x2 = affinityMask.to_ullong();
state.ctx->gpr.w1 = idealCore; state.ctx->gpr.w1 = idealCore;
@ -386,7 +388,7 @@ namespace skyline::kernel::svc {
return; return;
} }
state.logger->Debug("svcSetThreadCoreMask: Setting thread #{}'s Ideal Core ({}) + Affinity Mask ({})", thread->id, idealCore, affinityMask); state.logger->Debug("svcSetThreadCoreMask: Setting Ideal Core ({}) + Affinity Mask ({})", idealCore, affinityMask);
thread->idealCore = idealCore; thread->idealCore = idealCore;
thread->affinityMask = affinityMask; thread->affinityMask = affinityMask;
@ -396,7 +398,8 @@ namespace skyline::kernel::svc {
state.scheduler->RemoveThread(); state.scheduler->RemoveThread();
thread->coreId = idealCore; thread->coreId = idealCore;
state.scheduler->InsertThread(false); state.scheduler->InsertThread(state.thread, false);
state.scheduler->WaitSchedule();
} }
state.ctx->gpr.w0 = Result{}; state.ctx->gpr.w0 = Result{};
@ -407,8 +410,9 @@ namespace skyline::kernel::svc {
} }
void GetCurrentProcessorNumber(const DeviceState &state) { void GetCurrentProcessorNumber(const DeviceState &state) {
state.logger->Debug("svcGetCurrentProcessorNumber: Writing current core for thread #{}: {}", state.thread->id, state.thread->coreId); auto coreId{state.thread->coreId};
state.ctx->gpr.w0 = state.thread->coreId; state.logger->Debug("svcGetCurrentProcessorNumber: Writing current core: {}", coreId);
state.ctx->gpr.w0 = coreId;
} }
void ClearEvent(const DeviceState &state) { void ClearEvent(const DeviceState &state) {
@ -611,12 +615,15 @@ namespace skyline::kernel::svc {
state.logger->Debug("svcArbitrateLock: Locking mutex at 0x{:X}", pointer); state.logger->Debug("svcArbitrateLock: Locking mutex at 0x{:X}", pointer);
if (state.process->MutexLock(pointer, ownerHandle)) auto result{state.process->MutexLock(pointer, ownerHandle)};
if (result == Result{})
state.logger->Debug("svcArbitrateLock: Locked mutex at 0x{:X}", pointer); state.logger->Debug("svcArbitrateLock: Locked mutex at 0x{:X}", pointer);
else else if (result == result::InvalidHandle)
state.logger->Warn("svcArbitrateLock: 'handle' invalid: 0x{:X}", ownerHandle);
else if (result == result::InvalidCurrentMemory)
state.logger->Debug("svcArbitrateLock: Owner handle did not match current owner for mutex or didn't have waiter flag at 0x{:X}", pointer); state.logger->Debug("svcArbitrateLock: Owner handle did not match current owner for mutex or didn't have waiter flag at 0x{:X}", pointer);
state.ctx->gpr.w0 = Result{}; state.ctx->gpr.w0 = result;
} }
void ArbitrateUnlock(const DeviceState &state) { void ArbitrateUnlock(const DeviceState &state) {
@ -629,13 +636,10 @@ namespace skyline::kernel::svc {
state.logger->Debug("svcArbitrateUnlock: Unlocking mutex at 0x{:X}", mutex); state.logger->Debug("svcArbitrateUnlock: Unlocking mutex at 0x{:X}", mutex);
if (state.process->MutexUnlock(mutex)) { state.process->MutexUnlock(mutex);
state.logger->Debug("svcArbitrateUnlock: Unlocked mutex at 0x{:X}", mutex); state.logger->Debug("svcArbitrateUnlock: Unlocked mutex at 0x{:X}", mutex);
state.ctx->gpr.w0 = Result{}; state.ctx->gpr.w0 = Result{};
} else {
state.logger->Debug("svcArbitrateUnlock: A non-owner thread tried to release a mutex at 0x{:X}", mutex);
state.ctx->gpr.w0 = result::InvalidAddress;
}
} }
void WaitProcessWideKeyAtomic(const DeviceState &state) { void WaitProcessWideKeyAtomic(const DeviceState &state) {
@ -651,11 +655,7 @@ namespace skyline::kernel::svc {
if (handle != state.thread->handle) if (handle != state.thread->handle)
throw exception("svcWaitProcessWideKeyAtomic: Handle doesn't match current thread: 0x{:X} for thread 0x{:X}", handle, state.thread->handle); throw exception("svcWaitProcessWideKeyAtomic: Handle doesn't match current thread: 0x{:X} for thread 0x{:X}", handle, state.thread->handle);
if (!state.process->MutexUnlock(mutex)) { state.process->MutexUnlock(mutex);
state.logger->Debug("WaitProcessWideKeyAtomic: A non-owner thread tried to release a mutex at 0x{:X}", mutex);
state.ctx->gpr.w0 = result::InvalidAddress;
return;
}
u64 timeout{state.ctx->gpr.x3}; u64 timeout{state.ctx->gpr.x3};
state.logger->Debug("svcWaitProcessWideKeyAtomic: Mutex: 0x{:X}, Conditional-Variable: 0x{:X}, Timeout: {} ns", mutex, conditional, timeout); state.logger->Debug("svcWaitProcessWideKeyAtomic: Mutex: 0x{:X}, Conditional-Variable: 0x{:X}, Timeout: {} ns", mutex, conditional, timeout);
@ -731,7 +731,7 @@ namespace skyline::kernel::svc {
if (debug.back() == '\n') if (debug.back() == '\n')
debug.remove_suffix(1); debug.remove_suffix(1);
state.logger->Info("Debug Output: {}", debug); state.logger->Info("svcOutputDebugString: {}", debug);
state.ctx->gpr.w0 = Result{}; state.ctx->gpr.w0 = Result{};
} }

156
app/src/main/cpp/skyline/kernel/types/KProcess.cpp
View File

@ -3,13 +3,10 @@
#include <nce.h> #include <nce.h>
#include <os.h> #include <os.h>
#include <kernel/results.h>
#include "KProcess.h" #include "KProcess.h"
namespace skyline::kernel::type { namespace skyline::kernel::type {
KProcess::WaitStatus::WaitStatus(u8 priority, KHandle handle) : priority(priority), handle(handle) {}
KProcess::WaitStatus::WaitStatus(u8 priority, KHandle handle, u32 *mutex) : priority(priority), handle(handle), mutex(mutex) {}
KProcess::TlsPage::TlsPage(const std::shared_ptr<KPrivateMemory> &memory) : memory(memory) {} KProcess::TlsPage::TlsPage(const std::shared_ptr<KPrivateMemory> &memory) : memory(memory) {}
u8 *KProcess::TlsPage::ReserveSlot() { u8 *KProcess::TlsPage::ReserveSlot() {
@ -112,72 +109,135 @@ namespace skyline::kernel::type {
return std::nullopt; return std::nullopt;
} }
bool KProcess::MutexLock(u32 *mutex, KHandle owner) { constexpr u32 HandleWaitMask{0x40000000}; //!< A mask of a bit which denotes if the handle has waiters or not
std::unique_lock lock(mutexLock);
auto &mtxWaiters{mutexes[reinterpret_cast<u64>(mutex)]};
if (mtxWaiters.empty()) { Result KProcess::MutexLock(u32 *mutex, KHandle ownerHandle) {
u32 mtxExpected{}; std::shared_ptr<KThread> owner;
if (__atomic_compare_exchange_n(mutex, &mtxExpected, (constant::MtxOwnerMask & state.thread->handle), false, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST)) try {
return true; owner = GetHandle<KThread>(ownerHandle & ~HandleWaitMask);
} catch (const std::out_of_range &) {
return result::InvalidHandle;
} }
if (__atomic_load_n(mutex, __ATOMIC_SEQ_CST) != (owner | ~constant::MtxOwnerMask)) bool isHighestPriority;
return false; {
std::lock_guard lock(owner->waiterMutex);
std::shared_ptr<WaitStatus> status; u32 value{};
for (auto it{mtxWaiters.begin()};; it++) { if (__atomic_compare_exchange_n(mutex, &value, (HandleWaitMask & state.thread->handle), false, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST))
if (it != mtxWaiters.end() && (*it)->priority >= state.thread->priority) // We try to do a CAS to get ownership of the mutex in the case that it's unoccupied
return {};
if (value != (ownerHandle | HandleWaitMask))
// We ensure that the mutex's value is the handle with the waiter bit set
return result::InvalidCurrentMemory;
auto &waiters{owner->waiters};
isHighestPriority = waiters.insert(std::upper_bound(waiters.begin(), waiters.end(), state.thread->priority.load(), KThread::IsHigherPriority), state.thread) == waiters.begin();
state.scheduler->RemoveThread();
std::atomic_store(&state.thread->waitThread, owner);
state.thread->waitKey = mutex;
}
if (isHighestPriority) {
// If we were the highest priority thread then we need to inherit priorities for all threads we're waiting on recursively
do {
u8 priority, ownerPriority;
do {
// Try to CAS the priority of the owner with the current thread
// If they're equivalent then we don't need to CAS as the priority won't be inherited
ownerPriority = owner->priority.load();
priority = std::min(ownerPriority, state.thread->priority.load());
} while (ownerPriority != priority && owner->priority.compare_exchange_strong(ownerPriority, priority));
if (ownerPriority != priority) {
auto waitThread{std::atomic_load(&owner->waitThread)};
while (waitThread) {
std::lock_guard lock(waitThread->waiterMutex);
auto currentWaitThread{std::atomic_load(&owner->waitThread)};
if (waitThread != currentWaitThread) {
waitThread = currentWaitThread;
continue; continue;
}
status = std::make_shared<WaitStatus>(state.thread->priority, state.thread->handle); // We need to update the location of the owner thread in the waiter queue of the thread it's waiting on
mtxWaiters.insert(it, status); auto &waiters{waitThread->waiters};
waiters.erase(std::find(waiters.begin(), waiters.end(), waitThread));
waiters.insert(std::upper_bound(waiters.begin(), waiters.end(), state.thread->priority.load(), KThread::IsHigherPriority), owner);
break; break;
} }
lock.unlock(); state.scheduler->UpdatePriority(owner);
while (!status->flag);
lock.lock();
status->flag = false;
for (auto it{mtxWaiters.begin()}; it != mtxWaiters.end(); it++) { owner = waitThread;
if ((*it)->handle == state.thread->handle) { } else {
mtxWaiters.erase(it);
break; break;
} }
} while (owner);
} }
return true; state.scheduler->WaitSchedule();
return {};
} }
bool KProcess::MutexUnlock(u32 *mutex) { void KProcess::MutexUnlock(u32 *mutex) {
std::unique_lock lock(mutexLock); std::lock_guard lock(state.thread->waiterMutex);
auto &waiters{state.thread->waiters};
auto nextOwnerIt{std::find_if(waiters.begin(), waiters.end(), [mutex](const std::shared_ptr<KThread> &thread) { return thread->waitKey == mutex; })};
if (nextOwnerIt != waiters.end()) {
auto nextOwner{*nextOwnerIt};
std::lock_guard nextLock(nextOwner->waiterMutex);
std::atomic_store(&nextOwner->waitThread, std::shared_ptr<KThread>{nullptr});
nextOwner->waitKey = nullptr;
auto &mtxWaiters{mutexes[reinterpret_cast<u64>(mutex)]}; // Move all threads waiting on this key to the next owner's waiter list
u32 mtxDesired{}; std::shared_ptr<KThread> nextWaiter{};
if (!mtxWaiters.empty()) for (auto it{waiters.erase(nextOwnerIt)}; it != waiters.end(); it++) {
mtxDesired = (*mtxWaiters.begin())->handle | ((mtxWaiters.size() > 1) ? ~constant::MtxOwnerMask : 0); if ((*it)->waitKey == mutex) {
nextOwner->waiters.splice(std::upper_bound(nextOwner->waiters.begin(), nextOwner->waiters.end(), (*it)->priority.load(), KThread::IsHigherPriority), waiters, it);
u32 mtxExpected{(constant::MtxOwnerMask & state.thread->handle) | ~constant::MtxOwnerMask}; std::atomic_store(&(*it)->waitThread, nextOwner);
if (!__atomic_compare_exchange_n(mutex, &mtxExpected, mtxDesired, false, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST)) { if (!nextWaiter)
mtxExpected &= constant::MtxOwnerMask; nextWaiter = *it;
}
if (!__atomic_compare_exchange_n(mutex, &mtxExpected, mtxDesired, false, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST))
return false;
} }
if (mtxDesired) { if (!waiters.empty()) {
auto status{(*mtxWaiters.begin())}; // If there are threads still waiting on us then try to inherit their priority
status->flag = true; auto highestPriority{waiters.front()};
lock.unlock(); u8 priority, ownerPriority;
while (status->flag); do {
lock.lock(); ownerPriority = state.thread->priority.load();
priority = std::min(ownerPriority, highestPriority->priority.load());
} while (ownerPriority != priority && nextOwner->priority.compare_exchange_strong(ownerPriority, priority));
state.scheduler->UpdatePriority(state.thread);
} }
return true; if (nextWaiter) {
// If there is a waiter on the new owner then try to inherit it's priority
u8 priority, ownerPriority;
do {
ownerPriority = nextOwner->priority.load();
priority = std::min(ownerPriority, nextWaiter->priority.load());
} while (ownerPriority != priority && nextOwner->priority.compare_exchange_strong(ownerPriority, priority));
__atomic_store_n(mutex, nextOwner->handle | HandleWaitMask, __ATOMIC_SEQ_CST);
} else {
__atomic_store_n(mutex, nextOwner->handle, __ATOMIC_SEQ_CST);
}
// Finally, schedule the next owner accordingly
state.scheduler->InsertThread(nextOwner, false);
} else {
__atomic_store_n(mutex, 0, __ATOMIC_SEQ_CST);
return;
}
} }
bool KProcess::ConditionalVariableWait(void *conditional, u32 *mutex, u64 timeout) { bool KProcess::ConditionalVariableWait(void *conditional, u32 *mutex, u64 timeout) {
/* FIXME
std::unique_lock lock(conditionalLock); std::unique_lock lock(conditionalLock);
auto &condWaiters{conditionals[reinterpret_cast<u64>(conditional)]}; auto &condWaiters{conditionals[reinterpret_cast<u64>(conditional)]};
@ -216,9 +276,12 @@ namespace skyline::kernel::type {
lock.unlock(); lock.unlock();
return !timedOut; return !timedOut;
*/
return false;
} }
void KProcess::ConditionalVariableSignal(void *conditional, u64 amount) { void KProcess::ConditionalVariableSignal(void *conditional, u64 amount) {
/* FIXME
std::unique_lock condLock(conditionalLock); std::unique_lock condLock(conditionalLock);
auto &condWaiters{conditionals[reinterpret_cast<u64>(conditional)]}; auto &condWaiters{conditionals[reinterpret_cast<u64>(conditional)]};
@ -282,5 +345,6 @@ namespace skyline::kernel::type {
while (thread->flag); while (thread->flag);
condLock.lock(); condLock.lock();
} }
*/
} }
} }

29
app/src/main/cpp/skyline/kernel/types/KProcess.h
View File

@ -15,7 +15,6 @@ namespace skyline {
constexpr u16 TlsSlotSize{0x200}; //!< The size of a single TLS slot constexpr u16 TlsSlotSize{0x200}; //!< The size of a single TLS slot
constexpr u8 TlsSlots{PAGE_SIZE / TlsSlotSize}; //!< The amount of TLS slots in a single page constexpr u8 TlsSlots{PAGE_SIZE / TlsSlotSize}; //!< The amount of TLS slots in a single page
constexpr KHandle BaseHandleIndex{0xD000}; //!< The index of the base handle constexpr KHandle BaseHandleIndex{0xD000}; //!< The index of the base handle
constexpr u32 MtxOwnerMask{0xBFFFFFFF}; //!< The mask of values which contain the owner of a mutex
} }
namespace kernel::type { namespace kernel::type {
@ -27,22 +26,6 @@ namespace skyline {
MemoryManager memory; MemoryManager memory;
private: private:
struct WaitStatus {
std::atomic_bool flag{false};
u8 priority;
KHandle handle;
u32 *mutex{};
WaitStatus(u8 priority, KHandle handle);
WaitStatus(u8 priority, KHandle handle, u32 *mutex);
};
std::unordered_map<u64, std::vector<std::shared_ptr<WaitStatus>>> mutexes; //!< A map from a mutex's address to a vector of Mutex objects for threads waiting on it
std::unordered_map<u64, std::list<std::shared_ptr<WaitStatus>>> conditionals; //!< A map from a conditional variable's address to a vector of threads waiting on it
std::mutex mutexLock;
std::mutex conditionalLock;
std::mutex threadMutex; //!< Synchronizes thread creation to prevent a race between thread creation and thread killing std::mutex threadMutex; //!< Synchronizes thread creation to prevent a race between thread creation and thread killing
bool disableThreadCreation{}; //!< If to disable thread creation, we use this to prevent thread creation after all threads have been killed bool disableThreadCreation{}; //!< If to disable thread creation, we use this to prevent thread creation after all threads have been killed
std::vector<std::shared_ptr<KThread>> threads; std::vector<std::shared_ptr<KThread>> threads;
@ -208,17 +191,15 @@ namespace skyline {
} }
/** /**
* @brief Locks the Mutex at the specified address * @brief Locks the mutex at the specified address
* @param owner The handle of the current mutex owner * @param ownerHandle The psuedo-handle of the current mutex owner
* @return If the mutex was successfully locked
*/ */
bool MutexLock(u32 *mutex, KHandle owner); Result MutexLock(u32 *mutex, KHandle ownerHandle);
/** /**
* @brief Unlocks the Mutex at the specified address * @brief Unlocks the mutex at the specified address
* @return If the mutex was successfully unlocked
*/ */
bool MutexUnlock(u32 *mutex); void MutexUnlock(u32 *mutex);
/** /**
* @param timeout The amount of time to wait for the conditional variable * @param timeout The amount of time to wait for the conditional variable

2
app/src/main/cpp/skyline/kernel/types/KThread.cpp
View File

@ -58,7 +58,7 @@ namespace skyline::kernel::type {
signal::SetSignalHandler({SIGINT, SIGILL, SIGTRAP, SIGBUS, SIGFPE, SIGSEGV}, nce::NCE::SignalHandler); signal::SetSignalHandler({SIGINT, SIGILL, SIGTRAP, SIGBUS, SIGFPE, SIGSEGV}, nce::NCE::SignalHandler);
try { try {
state.scheduler->InsertThread(); state.scheduler->InsertThread(state.thread);
state.scheduler->WaitSchedule(); state.scheduler->WaitSchedule();
asm volatile( asm volatile(

15
app/src/main/cpp/skyline/kernel/types/KThread.h
View File

@ -3,6 +3,7 @@
#pragma once #pragma once
#include <list>
#include <csetjmp> #include <csetjmp>
#include <nce/guest.h> #include <nce/guest.h>
#include <kernel/scheduler.h> #include <kernel/scheduler.h>
@ -38,16 +39,21 @@ namespace skyline {
u64 entryArgument; u64 entryArgument;
void *stackTop; void *stackTop;
std::atomic<u8> basePriority; //!< The priority of the thread for the scheduler without any priority-inheritance
std::atomic<u8> priority; //!< The priority of the thread for the scheduler std::atomic<u8> priority; //!< The priority of the thread for the scheduler
i8 idealCore; //!< The ideal CPU core for this thread to run on i8 idealCore; //!< The ideal CPU core for this thread to run on
i8 coreId; //!< The CPU core on which this thread is running i8 coreId; //!< The CPU core on which this thread is running
CoreMask affinityMask{}; //!< A mask of CPU cores this thread is allowed to run on CoreMask affinityMask{}; //!< A mask of CPU cores this thread is allowed to run on
std::mutex coreMigrationMutex; //!< Synchronizes operations which depend on which core the thread is running on
u64 timesliceStart{}; //!< Start of the scheduler timeslice u64 timesliceStart{}; //!< Start of the scheduler timeslice
u64 averageTimeslice{}; //!< A weighted average of the timeslice duration for this thread u64 averageTimeslice{}; //!< A weighted average of the timeslice duration for this thread
std::optional<timer_t> preemptionTimer{}; //!< A kernel timer used for preemption interrupts std::optional<timer_t> preemptionTimer{}; //!< A kernel timer used for preemption interrupts
bool isPreempted{}; //!< If the preemption timer has been armed and will fire bool isPreempted{}; //!< If the preemption timer has been armed and will fire
bool needsReorder{}; //!< If the thread needs to reorder itself during scheduler rotation bool needsReorder{}; //!< If the thread needs to reorder itself during scheduler rotation
std::mutex coreMigrationMutex; //!< Synchronizes operations which depend on which core the thread is running on std::mutex waiterMutex; //!< Synchronizes operations on mutation of the waiter members
u32* waitKey; //!< The key on which this thread is waiting on
std::shared_ptr<KThread> waitThread; //!< The thread which this thread is waiting on
std::list<std::shared_ptr<type::KThread>> waiters; //!< A queue of threads waiting on this thread sorted by priority
KThread(const DeviceState &state, KHandle handle, KProcess *parent, size_t id, void *entry, u64 argument, void *stackTop, u8 priority, i8 idealCore); KThread(const DeviceState &state, KHandle handle, KProcess *parent, size_t id, void *entry, u64 argument, void *stackTop, u8 priority, i8 idealCore);
@ -69,6 +75,13 @@ namespace skyline {
* @brief Sends a host OS signal to the thread which is running this KThread * @brief Sends a host OS signal to the thread which is running this KThread
*/ */
void SendSignal(int signal); void SendSignal(int signal);
/**
* @return If the supplied priority value is higher than the current thread
*/
static constexpr bool IsHigherPriority(const i8 priority, const std::shared_ptr<type::KThread> &it) {
return priority < it->priority;
}
}; };
} }
} }