From 48f4c526f359b089559454703cedff8d8533fa37 Mon Sep 17 00:00:00 2001 From: Michael Scire Date: Tue, 21 Feb 2023 13:15:01 -0700 Subject: [PATCH] kern: refactor priority inheritance to represent locks as C++ objects --- .../include/mesosphere/kern_k_thread.hpp | 113 ++++++++- .../source/init/kern_init_slab_setup.cpp | 4 +- .../source/kern_k_condition_variable.cpp | 16 +- .../source/kern_k_light_lock.cpp | 6 +- .../libmesosphere/source/kern_k_process.cpp | 4 +- .../libmesosphere/source/kern_k_scheduler.cpp | 2 +- .../libmesosphere/source/kern_k_thread.cpp | 228 ++++++++++++------ 7 files changed, 271 insertions(+), 102 deletions(-) diff --git a/libraries/libmesosphere/include/mesosphere/kern_k_thread.hpp b/libraries/libmesosphere/include/mesosphere/kern_k_thread.hpp index a5e8db8d1..b6d3c67fa 100644 --- a/libraries/libmesosphere/include/mesosphere/kern_k_thread.hpp +++ b/libraries/libmesosphere/include/mesosphere/kern_k_thread.hpp @@ -201,6 +201,28 @@ namespace ams::kern { }; static_assert(ams::util::HasRedBlackKeyType); static_assert(std::same_as, ConditionVariableComparator::RedBlackKeyType>); + + struct LockWithPriorityInheritanceComparator { + struct RedBlackKeyType { + s32 m_priority; + + constexpr ALWAYS_INLINE s32 GetPriority() const { + return m_priority; + } + }; + + template requires (std::same_as || std::same_as) + static constexpr ALWAYS_INLINE int Compare(const T &lhs, const KThread &rhs) { + if (lhs.GetPriority() < rhs.GetPriority()) { + /* And then by priority. */ + return -1; + } else { + return 1; + } + } + }; + static_assert(ams::util::HasRedBlackKeyType); + static_assert(std::same_as, LockWithPriorityInheritanceComparator::RedBlackKeyType>); private: util::IntrusiveListNode m_process_list_node; util::IntrusiveRedBlackTreeNode m_condvar_arbiter_tree_node; @@ -209,6 +231,67 @@ namespace ams::kern { using ConditionVariableThreadTreeTraits = util::IntrusiveRedBlackTreeMemberTraitsDeferredAssert<&KThread::m_condvar_arbiter_tree_node>; using ConditionVariableThreadTree = ConditionVariableThreadTreeTraits::TreeType; + using LockWithPriorityInheritanceThreadTreeTraits = util::IntrusiveRedBlackTreeMemberTraitsDeferredAssert<&KThread::m_condvar_arbiter_tree_node>; + using LockWithPriorityInheritanceThreadTree = ConditionVariableThreadTreeTraits::TreeType; + public: + class LockWithPriorityInheritanceInfo : public KSlabAllocated, public util::IntrusiveListBaseNode { + private: + LockWithPriorityInheritanceThreadTree m_tree; + KProcessAddress m_address_key; + KThread *m_owner; + u32 m_waiter_count; + public: + constexpr LockWithPriorityInheritanceInfo() : m_tree(), m_address_key(Null), m_owner(nullptr), m_waiter_count() { + /* ... */ + } + + static LockWithPriorityInheritanceInfo *Create(KProcessAddress address_key) { + /* Create a new lock info. */ + auto *new_lock = LockWithPriorityInheritanceInfo::Allocate(); + MESOSPHERE_ABORT_UNLESS(new_lock != nullptr); + + /* Set the new lock's address key. */ + new_lock->m_address_key = address_key; + + return new_lock; + } + + void SetOwner(KThread *new_owner) { + /* Set new owner. */ + m_owner = new_owner; + } + + void AddWaiter(KThread *waiter) { + /* Insert the waiter. */ + m_tree.insert(*waiter); + m_waiter_count++; + + waiter->SetWaitingLockInfo(this); + } + + [[nodiscard]] bool RemoveWaiter(KThread *waiter) { + m_tree.erase(m_tree.iterator_to(*waiter)); + + waiter->SetWaitingLockInfo(nullptr); + + return (--m_waiter_count) == 0; + } + + KThread *GetHighestPriorityWaiter() { return std::addressof(m_tree.front()); } + const KThread *GetHighestPriorityWaiter() const { return std::addressof(m_tree.front()); } + + LockWithPriorityInheritanceThreadTree &GetThreadTree() { return m_tree; } + const LockWithPriorityInheritanceThreadTree &GetThreadTree() const { return m_tree; } + + constexpr KProcessAddress GetAddressKey() const { return m_address_key; } + + constexpr KThread *GetOwner() const { return m_owner; } + + constexpr u32 GetWaiterCount() const { return m_waiter_count; } + }; + private: + using LockWithPriorityInheritanceInfoList = util::IntrusiveListBaseTraits::ListType; + ConditionVariableThreadTree *m_condvar_tree; uintptr_t m_condvar_key; alignas(16) KThreadContext::CallerSaveFpuRegisters m_caller_save_fpu_registers; @@ -228,9 +311,9 @@ namespace ams::kern { s64 m_last_scheduled_tick; QueueEntry m_per_core_priority_queue_entry[cpu::NumCores]; KThreadQueue *m_wait_queue; - WaiterList m_waiter_list; + LockWithPriorityInheritanceInfoList m_held_lock_info_list; + LockWithPriorityInheritanceInfo *m_waiting_lock_info; WaiterList m_pinned_waiter_list; - KThread *m_lock_owner; uintptr_t m_debug_params[3]; KAutoObject *m_closed_object; u32 m_address_key_value; @@ -264,8 +347,8 @@ namespace ams::kern { m_process_list_node{}, m_condvar_arbiter_tree_node{util::ConstantInitialize}, m_priority{-1}, m_condvar_tree{}, m_condvar_key{}, m_caller_save_fpu_registers{}, m_virtual_affinity_mask{}, m_physical_affinity_mask{}, m_thread_id{}, m_cpu_time{0}, m_address_key{Null}, m_parent{}, m_kernel_stack_top{}, m_light_ipc_data{}, m_tls_address{Null}, m_tls_heap_address{}, m_activity_pause_lock{}, m_sync_object_buffer{util::ConstantInitialize}, - m_schedule_count{}, m_last_scheduled_tick{}, m_per_core_priority_queue_entry{}, m_wait_queue{}, m_waiter_list{}, m_pinned_waiter_list{}, - m_lock_owner{}, m_debug_params{}, m_closed_object{}, m_address_key_value{}, m_suspend_request_flags{}, m_suspend_allowed_flags{}, m_synced_index{}, + m_schedule_count{}, m_last_scheduled_tick{}, m_per_core_priority_queue_entry{}, m_wait_queue{}, m_held_lock_info_list{}, m_pinned_waiter_list{}, + m_waiting_lock_info{}, m_debug_params{}, m_closed_object{}, m_address_key_value{}, m_suspend_request_flags{}, m_suspend_allowed_flags{}, m_synced_index{}, m_wait_result{svc::ResultNoSynchronizationObject()}, m_debug_exception_result{ResultSuccess()}, m_base_priority{}, m_base_priority_on_unpin{}, m_physical_ideal_core_id{}, m_virtual_ideal_core_id{}, m_num_kernel_waiters{}, m_current_core_id{}, m_core_id{}, m_original_physical_affinity_mask{}, m_original_physical_ideal_core_id{}, m_num_core_migration_disables{}, m_thread_state{}, m_termination_requested{false}, m_wait_cancelled{}, @@ -411,6 +494,10 @@ namespace ams::kern { void ClearUsermodeExceptionSvcPermissions(); private: void UpdateState(); + + ALWAYS_INLINE void AddHeldLock(LockWithPriorityInheritanceInfo *lock_info); + ALWAYS_INLINE LockWithPriorityInheritanceInfo *FindHeldLock(KProcessAddress address_key); + ALWAYS_INLINE void AddWaiterImpl(KThread *thread); ALWAYS_INLINE void RemoveWaiterImpl(KThread *thread); ALWAYS_INLINE static void RestorePriority(KThread *thread); @@ -445,6 +532,8 @@ namespace ams::kern { constexpr uintptr_t GetAddressArbiterKey() const { return m_condvar_key; } constexpr void SetConditionVariable(ConditionVariableThreadTree *tree, KProcessAddress address, uintptr_t cv_key, u32 value) { + MESOSPHERE_ASSERT(m_waiting_lock_info == nullptr); + m_condvar_tree = tree; m_condvar_key = cv_key; m_address_key = address; @@ -460,6 +549,8 @@ namespace ams::kern { } constexpr void SetAddressArbiter(ConditionVariableThreadTree *tree, uintptr_t address) { + MESOSPHERE_ASSERT(m_waiting_lock_info == nullptr); + m_condvar_tree = tree; m_condvar_key = address; } @@ -495,15 +586,17 @@ namespace ams::kern { void AddWaiter(KThread *thread); void RemoveWaiter(KThread *thread); - KThread *RemoveWaiterByKey(s32 *out_num_waiters, KProcessAddress key); + KThread *RemoveWaiterByKey(bool *out_has_waiters, KProcessAddress key); constexpr KProcessAddress GetAddressKey() const { return m_address_key; } constexpr u32 GetAddressKeyValue() const { return m_address_key_value; } - constexpr void SetAddressKey(KProcessAddress key) { m_address_key = key; } - constexpr void SetAddressKey(KProcessAddress key, u32 val) { m_address_key = key; m_address_key_value = val; } + constexpr void SetAddressKey(KProcessAddress key) { MESOSPHERE_ASSERT(m_waiting_lock_info == nullptr); m_address_key = key; } + constexpr void SetAddressKey(KProcessAddress key, u32 val) { MESOSPHERE_ASSERT(m_waiting_lock_info == nullptr); m_address_key = key; m_address_key_value = val; } - constexpr void SetLockOwner(KThread *owner) { m_lock_owner = owner; } - constexpr KThread *GetLockOwner() const { return m_lock_owner; } + constexpr void SetWaitingLockInfo(LockWithPriorityInheritanceInfo *lock) { m_waiting_lock_info = lock; } + constexpr LockWithPriorityInheritanceInfo *GetWaitingLockInfo() { return m_waiting_lock_info; } + + constexpr KThread *GetLockOwner() const { return m_waiting_lock_info != nullptr ? m_waiting_lock_info->GetOwner() : nullptr; } constexpr void ClearWaitQueue() { m_wait_queue = nullptr; } @@ -533,8 +626,6 @@ namespace ams::kern { constexpr u32 *GetLightSessionData() const { return m_light_ipc_data; } constexpr void SetLightSessionData(u32 *data) { m_light_ipc_data = data; } - bool HasWaiters() const { return !m_waiter_list.empty(); } - constexpr s64 GetLastScheduledTick() const { return m_last_scheduled_tick; } constexpr void SetLastScheduledTick(s64 tick) { m_last_scheduled_tick = tick; } diff --git a/libraries/libmesosphere/source/init/kern_init_slab_setup.cpp b/libraries/libmesosphere/source/init/kern_init_slab_setup.cpp index 84be8a839..1d76900ee 100644 --- a/libraries/libmesosphere/source/init/kern_init_slab_setup.cpp +++ b/libraries/libmesosphere/source/init/kern_init_slab_setup.cpp @@ -19,6 +19,7 @@ namespace ams::kern::init { /* For macro convenience. */ using KSessionRequestMappings = KSessionRequest::SessionMappings::DynamicMappings; + using KThreadLockInfo = KThread::LockWithPriorityInheritanceInfo; #define SLAB_COUNT(CLASS) g_slab_resource_counts.num_##CLASS @@ -43,8 +44,9 @@ namespace ams::kern::init { HANDLER(KDebug, (SLAB_COUNT(KDebug)), ## __VA_ARGS__) \ HANDLER(KIoPool, (SLAB_COUNT(KIoPool)), ## __VA_ARGS__) \ HANDLER(KIoRegion, (SLAB_COUNT(KIoRegion)), ## __VA_ARGS__) \ + HANDLER(KSessionRequestMappings, (SLAB_COUNT(KSessionRequestMappings)), ## __VA_ARGS__) \ HANDLER(KSecureSystemResource, (SLAB_COUNT(KProcess)), ## __VA_ARGS__) \ - HANDLER(KSessionRequestMappings, (SLAB_COUNT(KSessionRequestMappings)), ## __VA_ARGS__) + HANDLER(KThreadLockInfo, (SLAB_COUNT(KThread)), ## __VA_ARGS__) namespace { diff --git a/libraries/libmesosphere/source/kern_k_condition_variable.cpp b/libraries/libmesosphere/source/kern_k_condition_variable.cpp index 59ed56362..14b25d623 100644 --- a/libraries/libmesosphere/source/kern_k_condition_variable.cpp +++ b/libraries/libmesosphere/source/kern_k_condition_variable.cpp @@ -77,14 +77,14 @@ namespace ams::kern { KScopedSchedulerLock sl; /* Remove waiter thread. */ - s32 num_waiters; - KThread * const next_owner_thread = owner_thread->RemoveWaiterByKey(std::addressof(num_waiters), addr); + bool has_waiters; + KThread * const next_owner_thread = owner_thread->RemoveWaiterByKey(std::addressof(has_waiters), addr); /* Determine the next tag. */ u32 next_value = 0; if (next_owner_thread != nullptr) { next_value = next_owner_thread->GetAddressKeyValue(); - if (num_waiters > 1) { + if (has_waiters) { next_value |= ams::svc::HandleWaitMask; } } @@ -200,9 +200,11 @@ namespace ams::kern { while ((it != m_tree.end()) && (count <= 0 || num_waiters < count) && (it->GetConditionVariableKey() == cv_key)) { KThread *target_thread = std::addressof(*it); - this->SignalImpl(target_thread); it = m_tree.erase(it); target_thread->ClearConditionVariable(); + + this->SignalImpl(target_thread); + ++num_waiters; } @@ -232,15 +234,15 @@ namespace ams::kern { /* Update the value and process for the next owner. */ { /* Remove waiter thread. */ - s32 num_waiters; - KThread *next_owner_thread = cur_thread->RemoveWaiterByKey(std::addressof(num_waiters), GetInteger(addr)); + bool has_waiters; + KThread *next_owner_thread = cur_thread->RemoveWaiterByKey(std::addressof(has_waiters), GetInteger(addr)); /* Update for the next owner thread. */ u32 next_value = 0; if (next_owner_thread != nullptr) { /* Get the next tag value. */ next_value = next_owner_thread->GetAddressKeyValue(); - if (num_waiters > 1) { + if (has_waiters) { next_value |= ams::svc::HandleWaitMask; } diff --git a/libraries/libmesosphere/source/kern_k_light_lock.cpp b/libraries/libmesosphere/source/kern_k_light_lock.cpp index 3c488b370..f9d928b5d 100644 --- a/libraries/libmesosphere/source/kern_k_light_lock.cpp +++ b/libraries/libmesosphere/source/kern_k_light_lock.cpp @@ -68,13 +68,13 @@ namespace ams::kern { KScopedSchedulerLock sl; /* Get the next owner. */ - s32 num_waiters; - KThread *next_owner = owner_thread->RemoveWaiterByKey(std::addressof(num_waiters), reinterpret_cast(std::addressof(m_tag))); + bool has_waiters; + KThread *next_owner = owner_thread->RemoveWaiterByKey(std::addressof(has_waiters), reinterpret_cast(std::addressof(m_tag))); /* Pass the lock to the next owner. */ uintptr_t next_tag = 0; if (next_owner != nullptr) { - next_tag = reinterpret_cast(next_owner) | static_cast(num_waiters > 1); + next_tag = reinterpret_cast(next_owner) | static_cast(has_waiters); next_owner->EndWait(ResultSuccess()); diff --git a/libraries/libmesosphere/source/kern_k_process.cpp b/libraries/libmesosphere/source/kern_k_process.cpp index 94b0a313f..7768833d1 100644 --- a/libraries/libmesosphere/source/kern_k_process.cpp +++ b/libraries/libmesosphere/source/kern_k_process.cpp @@ -817,8 +817,8 @@ namespace ams::kern { m_exception_thread = nullptr; /* Remove waiter thread. */ - s32 num_waiters; - if (KThread *next = thread->RemoveWaiterByKey(std::addressof(num_waiters), reinterpret_cast(std::addressof(m_exception_thread)) | 1); next != nullptr) { + bool has_waiters; + if (KThread *next = thread->RemoveWaiterByKey(std::addressof(has_waiters), reinterpret_cast(std::addressof(m_exception_thread)) | 1); next != nullptr) { next->EndWait(ResultSuccess()); } diff --git a/libraries/libmesosphere/source/kern_k_scheduler.cpp b/libraries/libmesosphere/source/kern_k_scheduler.cpp index 167474234..34fc4aea3 100644 --- a/libraries/libmesosphere/source/kern_k_scheduler.cpp +++ b/libraries/libmesosphere/source/kern_k_scheduler.cpp @@ -243,7 +243,7 @@ namespace ams::kern { if (AMS_LIKELY(!cur_thread->IsTerminationRequested()) && AMS_LIKELY(cur_thread->GetActiveCore() == m_core_id)) { m_state.prev_thread = cur_thread; } else { - m_state.prev_thread =nullptr; + m_state.prev_thread = nullptr; } } diff --git a/libraries/libmesosphere/source/kern_k_thread.cpp b/libraries/libmesosphere/source/kern_k_thread.cpp index 4149409d4..942e85b10 100644 --- a/libraries/libmesosphere/source/kern_k_thread.cpp +++ b/libraries/libmesosphere/source/kern_k_thread.cpp @@ -254,7 +254,7 @@ namespace ams::kern { m_light_ipc_data = nullptr; /* We're not waiting for a lock, and we haven't disabled migration. */ - m_lock_owner = nullptr; + m_waiting_lock_info = nullptr; m_num_core_migration_disables = 0; /* We have no waiters, and no closed objects. */ @@ -397,25 +397,39 @@ namespace ams::kern { /* Release any waiters. */ { - MESOSPHERE_ASSERT(m_lock_owner == nullptr); + MESOSPHERE_ASSERT(m_waiting_lock_info == nullptr); KScopedSchedulerLock sl; - auto it = m_waiter_list.begin(); - while (it != m_waiter_list.end()) { - /* Get the thread. */ - KThread * const waiter = std::addressof(*it); + /* Check that we have no kernel waiters. */ + MESOSPHERE_ABORT_UNLESS(m_num_kernel_waiters == 0); - /* The thread shouldn't be a kernel waiter. */ - MESOSPHERE_ASSERT(!IsKernelAddressKey(waiter->GetAddressKey())); + auto it = m_held_lock_info_list.begin(); + while (it != m_held_lock_info_list.end()) { + /* Get the lock info. */ + auto * const lock_info = std::addressof(*it); - /* Clear the lock owner. */ - waiter->SetLockOwner(nullptr); + /* The lock shouldn't have a kernel waiter. */ + MESOSPHERE_ASSERT(!IsKernelAddressKey(lock_info->GetAddressKey())); - /* Erase the waiter from our list. */ - it = m_waiter_list.erase(it); + /* Remove all waiters. */ + while (lock_info->GetWaiterCount() != 0) { + /* Get the front waiter. */ + KThread * const waiter = lock_info->GetHighestPriorityWaiter(); - /* Cancel the thread's wait. */ - waiter->CancelWait(svc::ResultInvalidState(), true); + /* Remove it from the lock. */ + if (lock_info->RemoveWaiter(waiter)) { + MESOSPHERE_ASSERT(lock_info->GetWaiterCount() == 0); + } + + /* Cancel the thread's wait. */ + waiter->CancelWait(svc::ResultInvalidState(), true); + } + + /* Remove the held lock from our list. */ + it = m_held_lock_info_list.erase(it); + + /* Free the lock info. */ + LockWithPriorityInheritanceInfo::Free(lock_info); } } @@ -823,11 +837,8 @@ namespace ams::kern { void KThread::IncreaseBasePriority(s32 priority) { MESOSPHERE_ASSERT_THIS(); MESOSPHERE_ASSERT(ams::svc::HighestThreadPriority <= priority && priority <= ams::svc::LowestThreadPriority); - - /* Set our unpin base priority, if we're pinned. */ - if (this->GetStackParameters().is_pinned && m_base_priority_on_unpin > priority) { - m_base_priority_on_unpin = priority; - } + MESOSPHERE_ASSERT(KScheduler::IsSchedulerLockedByCurrentThread()); + MESOSPHERE_ASSERT(!this->GetStackParameters().is_pinned); /* Set our base priority. */ if (m_base_priority > priority) { @@ -1044,28 +1055,58 @@ namespace ams::kern { R_SUCCEED(); } - void KThread::AddWaiterImpl(KThread *thread) { + void KThread::AddHeldLock(LockWithPriorityInheritanceInfo *lock_info) { MESOSPHERE_ASSERT_THIS(); MESOSPHERE_ASSERT(KScheduler::IsSchedulerLockedByCurrentThread()); - /* Find the right spot to insert the waiter. */ - auto it = m_waiter_list.begin(); - while (it != m_waiter_list.end()) { - if (it->GetPriority() > thread->GetPriority()) { - break; + /* Set ourselves as the lock's owner. */ + lock_info->SetOwner(this); + + /* Add the lock to our held list. */ + m_held_lock_info_list.push_front(*lock_info); + } + + KThread::LockWithPriorityInheritanceInfo *KThread::FindHeldLock(KProcessAddress address_key) { + MESOSPHERE_ASSERT_THIS(); + MESOSPHERE_ASSERT(KScheduler::IsSchedulerLockedByCurrentThread()); + + /* Try to find an existing held lock. */ + for (auto &held_lock : m_held_lock_info_list) { + if (held_lock.GetAddressKey() == address_key) { + return std::addressof(held_lock); } - it++; } + return nullptr; + } + + + void KThread::AddWaiterImpl(KThread *thread) { + MESOSPHERE_ASSERT_THIS(); + MESOSPHERE_ASSERT(KScheduler::IsSchedulerLockedByCurrentThread()); + MESOSPHERE_ASSERT(thread->GetConditionVariableTree() == nullptr); + + /* Get the thread's address key. */ + const auto address_key = thread->GetAddressKey(); + /* Keep track of how many kernel waiters we have. */ - if (IsKernelAddressKey(thread->GetAddressKey())) { + if (IsKernelAddressKey(address_key)) { MESOSPHERE_ABORT_UNLESS((m_num_kernel_waiters++) >= 0); KScheduler::SetSchedulerUpdateNeeded(); } - /* Insert the waiter. */ - m_waiter_list.insert(it, *thread); - thread->SetLockOwner(this); + /* Get the relevant lock info. */ + auto *lock_info = this->FindHeldLock(address_key); + if (lock_info == nullptr) { + /* Create a new lock for the address key. */ + lock_info = LockWithPriorityInheritanceInfo::Create(address_key); + + /* Add the new lock to our list. */ + this->AddHeldLock(lock_info); + } + + /* Add the thread as waiter to the lock info. */ + lock_info->AddWaiter(thread); } void KThread::RemoveWaiterImpl(KThread *thread) { @@ -1078,19 +1119,25 @@ namespace ams::kern { KScheduler::SetSchedulerUpdateNeeded(); } + /* Get the info for the lock the thread is waiting on. */ + auto *lock_info = thread->GetWaitingLockInfo(); + MESOSPHERE_ASSERT(lock_info->GetOwner() == this); + /* Remove the waiter. */ - m_waiter_list.erase(m_waiter_list.iterator_to(*thread)); - thread->SetLockOwner(nullptr); + if (lock_info->RemoveWaiter(thread)) { + m_held_lock_info_list.erase(m_held_lock_info_list.iterator_to(*lock_info)); + LockWithPriorityInheritanceInfo::Free(lock_info); + } } void KThread::RestorePriority(KThread *thread) { MESOSPHERE_ASSERT(KScheduler::IsSchedulerLockedByCurrentThread()); - while (true) { + while (thread != nullptr) { /* We want to inherit priority where possible. */ s32 new_priority = thread->GetBasePriority(); - if (thread->HasWaiters()) { - new_priority = std::min(new_priority, thread->m_waiter_list.front().GetPriority()); + for (const auto &held_lock : thread->m_held_lock_info_list) { + new_priority = std::min(new_priority, held_lock.GetHighestPriorityWaiter()->GetPriority()); } /* If the priority we would inherit is not different from ours, don't do anything. */ @@ -1098,6 +1145,14 @@ namespace ams::kern { return; } + /* Get the owner of whatever lock this thread is waiting on. */ + KThread * const lock_owner = thread->GetLockOwner(); + + /* If the thread is waiting on some lock, remove it as a waiter to prevent violating red black tree invariants. */ + if (lock_owner != nullptr) { + lock_owner->RemoveWaiterImpl(thread); + } + /* Ensure we don't violate condition variable red black tree invariants. */ if (auto *cv_tree = thread->GetConditionVariableTree(); cv_tree != nullptr) { BeforeUpdatePriority(cv_tree, thread); @@ -1112,73 +1167,94 @@ namespace ams::kern { AfterUpdatePriority(cv_tree, thread); } + /* If we removed the thread from some lock's waiting list, add it back. */ + if (lock_owner != nullptr) { + lock_owner->AddWaiterImpl(thread); + } + /* Update the scheduler. */ KScheduler::OnThreadPriorityChanged(thread, old_priority); - /* Keep the lock owner up to date. */ - KThread *lock_owner = thread->GetLockOwner(); - if (lock_owner == nullptr) { - return; - } - - /* Update the thread in the lock owner's sorted list, and continue inheriting. */ - lock_owner->RemoveWaiterImpl(thread); - lock_owner->AddWaiterImpl(thread); + /* Continue inheriting priority. */ thread = lock_owner; } } void KThread::AddWaiter(KThread *thread) { MESOSPHERE_ASSERT_THIS(); + this->AddWaiterImpl(thread); - RestorePriority(this); + + /* If the thread has a higher priority than us, we should inherit. */ + if (thread->GetPriority() < this->GetPriority()) { + RestorePriority(this); + } } void KThread::RemoveWaiter(KThread *thread) { MESOSPHERE_ASSERT_THIS(); this->RemoveWaiterImpl(thread); - RestorePriority(this); + + /* If our priority is the same as the thread's (and we've inherited), we may need to restore to lower priority. */ + if (this->GetPriority() == thread->GetPriority() && this->GetPriority() < this->GetBasePriority()) { + RestorePriority(this); + } } - KThread *KThread::RemoveWaiterByKey(s32 *out_num_waiters, KProcessAddress key) { + KThread *KThread::RemoveWaiterByKey(bool *out_has_waiters, KProcessAddress key) { MESOSPHERE_ASSERT_THIS(); MESOSPHERE_ASSERT(KScheduler::IsSchedulerLockedByCurrentThread()); - s32 num_waiters = 0; - KThread *next_lock_owner = nullptr; - auto it = m_waiter_list.begin(); - while (it != m_waiter_list.end()) { - if (it->GetAddressKey() == key) { - KThread *thread = std::addressof(*it); + /* Get the relevant lock info. */ + auto *lock_info = this->FindHeldLock(key); + if (lock_info == nullptr) { + *out_has_waiters = false; + return nullptr; + } - /* Keep track of how many kernel waiters we have. */ - if (IsKernelAddressKey(thread->GetAddressKey())) { - MESOSPHERE_ABORT_UNLESS((m_num_kernel_waiters--) > 0); - KScheduler::SetSchedulerUpdateNeeded(); - } - it = m_waiter_list.erase(it); + /* Remove the lock info from our held list. */ + m_held_lock_info_list.erase(m_held_lock_info_list.iterator_to(*lock_info)); - /* Update the next lock owner. */ - if (next_lock_owner == nullptr) { - next_lock_owner = thread; - next_lock_owner->SetLockOwner(nullptr); - } else { - next_lock_owner->AddWaiterImpl(thread); - } - num_waiters++; - } else { - it++; + /* Keep track of how many kernel waiters we have. */ + if (IsKernelAddressKey(lock_info->GetAddressKey())) { + m_num_kernel_waiters -= lock_info->GetWaiterCount(); + MESOSPHERE_ABORT_UNLESS(m_num_kernel_waiters >= 0); + KScheduler::SetSchedulerUpdateNeeded(); + } + + MESOSPHERE_ASSERT(lock_info->GetWaiterCount() > 0); + + /* Remove the highest priority waiter from the lock to be the next owner. */ + KThread *next_lock_owner = lock_info->GetHighestPriorityWaiter(); + if (lock_info->RemoveWaiter(next_lock_owner)) { + /* The new owner was the only waiter. */ + *out_has_waiters = false; + + /* Free the lock info, since it has no waiters. */ + LockWithPriorityInheritanceInfo::Free(lock_info); + } else { + /* There are additional waiters on the lock. */ + *out_has_waiters = true; + + /* Add the lock to the new owner's held list. */ + next_lock_owner->AddHeldLock(lock_info); + + /* Keep track of any kernel waiters for the new owner. */ + if (IsKernelAddressKey(lock_info->GetAddressKey())) { + next_lock_owner->m_num_kernel_waiters += lock_info->GetWaiterCount(); + MESOSPHERE_ABORT_UNLESS(next_lock_owner->m_num_kernel_waiters > 0); + + /* NOTE: No need to set scheduler update needed, because we will have already done so when removing earlier. */ } } - /* Do priority updates, if we have a next owner. */ - if (next_lock_owner) { + /* If our priority is the same as the next owner's (and we've inherited), we may need to restore to lower priority. */ + if (this->GetPriority() == next_lock_owner->GetPriority() && this->GetPriority() < this->GetBasePriority()) { RestorePriority(this); - RestorePriority(next_lock_owner); + /* NOTE: No need to restore priority on the next lock owner, because it was already the highest priority waiter on the lock. */ } - /* Return output. */ - *out_num_waiters = num_waiters; + /* Return the next lock owner. */ return next_lock_owner; } @@ -1309,9 +1385,7 @@ namespace ams::kern { } /* Change the thread's priority to be higher than any system thread's. */ - if (this->GetBasePriority() >= ams::svc::SystemThreadPriorityHighest) { - this->SetBasePriority(TerminatingThreadPriority); - } + this->IncreaseBasePriority(TerminatingThreadPriority); /* If the thread is runnable, send a termination interrupt to other cores. */ if (this->GetState() == ThreadState_Runnable) {