kern: refactor priority inheritance to represent locks as C++ objects

This commit is contained in:
Michael Scire 2023-02-21 13:15:01 -07:00
parent 4f6ecf138b
commit adfaee0f46
7 changed files with 271 additions and 102 deletions

View file

@ -201,6 +201,28 @@ namespace ams::kern {
};
static_assert(ams::util::HasRedBlackKeyType<ConditionVariableComparator>);
static_assert(std::same_as<ams::util::RedBlackKeyType<ConditionVariableComparator, void>, ConditionVariableComparator::RedBlackKeyType>);
struct LockWithPriorityInheritanceComparator {
struct RedBlackKeyType {
s32 m_priority;
constexpr ALWAYS_INLINE s32 GetPriority() const {
return m_priority;
}
};
template<typename T> requires (std::same_as<T, KThread> || std::same_as<T, RedBlackKeyType>)
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<LockWithPriorityInheritanceComparator>);
static_assert(std::same_as<ams::util::RedBlackKeyType<LockWithPriorityInheritanceComparator, void>, 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<ConditionVariableComparator>;
using LockWithPriorityInheritanceThreadTreeTraits = util::IntrusiveRedBlackTreeMemberTraitsDeferredAssert<&KThread::m_condvar_arbiter_tree_node>;
using LockWithPriorityInheritanceThreadTree = ConditionVariableThreadTreeTraits::TreeType<LockWithPriorityInheritanceComparator>;
public:
class LockWithPriorityInheritanceInfo : public KSlabAllocated<LockWithPriorityInheritanceInfo>, public util::IntrusiveListBaseNode<LockWithPriorityInheritanceInfo> {
private:
LockWithPriorityInheritanceThreadTree m_tree;
KProcessAddress m_address_key;
KThread *m_owner;
u32 m_waiter_count;
public:
constexpr LockWithPriorityInheritanceInfo() : m_tree(), m_address_key(Null<KProcessAddress>), 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<LockWithPriorityInheritanceInfo>::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<KProcessAddress>}, m_parent{},
m_kernel_stack_top{}, m_light_ipc_data{}, m_tls_address{Null<KProcessAddress>}, 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; }

View file

@ -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 {

View file

@ -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;
}

View file

@ -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<uintptr_t>(std::addressof(m_tag)));
bool has_waiters;
KThread *next_owner = owner_thread->RemoveWaiterByKey(std::addressof(has_waiters), reinterpret_cast<uintptr_t>(std::addressof(m_tag)));
/* Pass the lock to the next owner. */
uintptr_t next_tag = 0;
if (next_owner != nullptr) {
next_tag = reinterpret_cast<uintptr_t>(next_owner) | static_cast<uintptr_t>(num_waiters > 1);
next_tag = reinterpret_cast<uintptr_t>(next_owner) | static_cast<uintptr_t>(has_waiters);
next_owner->EndWait(ResultSuccess());

View file

@ -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<uintptr_t>(std::addressof(m_exception_thread)) | 1); next != nullptr) {
bool has_waiters;
if (KThread *next = thread->RemoveWaiterByKey(std::addressof(has_waiters), reinterpret_cast<uintptr_t>(std::addressof(m_exception_thread)) | 1); next != nullptr) {
next->EndWait(ResultSuccess());
}

View file

@ -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;
}
}

View file

@ -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) {