hle: kernel: KLightLock: Migrate to updated KThreadQueue.

This commit is contained in:
bunnei 2021-11-09 20:51:47 -08:00
parent 15c721b909
commit 423acf53b7
2 changed files with 36 additions and 35 deletions

View file

@ -5,44 +5,54 @@
#include "core/hle/kernel/k_light_lock.h"
#include "core/hle/kernel/k_scheduler.h"
#include "core/hle/kernel/k_thread.h"
#include "core/hle/kernel/k_thread_queue.h"
#include "core/hle/kernel/kernel.h"
namespace Kernel {
namespace {
class ThreadQueueImplForKLightLock final : public KThreadQueue {
public:
explicit ThreadQueueImplForKLightLock(KernelCore& kernel_) : KThreadQueue(kernel_) {}
virtual void CancelWait([[maybe_unused]] KThread* waiting_thread,
[[maybe_unused]] ResultCode wait_result,
[[maybe_unused]] bool cancel_timer_task) override {
// Do nothing, waiting to acquire a light lock cannot be canceled.
}
};
} // namespace
void KLightLock::Lock() {
const uintptr_t cur_thread = reinterpret_cast<uintptr_t>(GetCurrentThreadPointer(kernel));
const uintptr_t cur_thread_tag = (cur_thread | 1);
while (true) {
uintptr_t old_tag = tag.load(std::memory_order_relaxed);
while (!tag.compare_exchange_weak(old_tag, (old_tag == 0) ? cur_thread : old_tag | 1,
while (!tag.compare_exchange_weak(old_tag, (old_tag == 0) ? cur_thread : (old_tag | 1),
std::memory_order_acquire)) {
if ((old_tag | 1) == cur_thread_tag) {
return;
}
}
if ((old_tag == 0) || ((old_tag | 1) == cur_thread_tag)) {
if (old_tag == 0 || this->LockSlowPath(old_tag | 1, cur_thread)) {
break;
}
LockSlowPath(old_tag | 1, cur_thread);
}
}
void KLightLock::Unlock() {
const uintptr_t cur_thread = reinterpret_cast<uintptr_t>(GetCurrentThreadPointer(kernel));
uintptr_t expected = cur_thread;
do {
if (expected != cur_thread) {
return UnlockSlowPath(cur_thread);
if (!tag.compare_exchange_strong(expected, 0, std::memory_order_release)) {
this->UnlockSlowPath(cur_thread);
}
} while (!tag.compare_exchange_weak(expected, 0, std::memory_order_release));
}
void KLightLock::LockSlowPath(uintptr_t _owner, uintptr_t _cur_thread) {
bool KLightLock::LockSlowPath(uintptr_t _owner, uintptr_t _cur_thread) {
KThread* cur_thread = reinterpret_cast<KThread*>(_cur_thread);
ThreadQueueImplForKLightLock wait_queue(kernel);
// Pend the current thread waiting on the owner thread.
{
@ -50,30 +60,23 @@ void KLightLock::LockSlowPath(uintptr_t _owner, uintptr_t _cur_thread) {
// Ensure we actually have locking to do.
if (tag.load(std::memory_order_relaxed) != _owner) {
return;
return false;
}
// Add the current thread as a waiter on the owner.
KThread* owner_thread = reinterpret_cast<KThread*>(_owner & ~1ULL);
KThread* owner_thread = reinterpret_cast<KThread*>(_owner & ~1ul);
cur_thread->SetAddressKey(reinterpret_cast<uintptr_t>(std::addressof(tag)));
owner_thread->AddWaiter(cur_thread);
// Set thread states.
cur_thread->SetState(ThreadState::Waiting);
// Begin waiting to hold the lock.
cur_thread->BeginWait(std::addressof(wait_queue));
if (owner_thread->IsSuspended()) {
owner_thread->ContinueIfHasKernelWaiters();
}
}
// We're no longer waiting on the lock owner.
{
KScopedSchedulerLock sl{kernel};
if (KThread* owner_thread = cur_thread->GetLockOwner(); owner_thread != nullptr) {
owner_thread->RemoveWaiter(cur_thread);
}
}
return true;
}
void KLightLock::UnlockSlowPath(uintptr_t _cur_thread) {
@ -81,22 +84,20 @@ void KLightLock::UnlockSlowPath(uintptr_t _cur_thread) {
// Unlock.
{
KScopedSchedulerLock sl{kernel};
KScopedSchedulerLock sl(kernel);
// Get the next owner.
s32 num_waiters = 0;
s32 num_waiters;
KThread* next_owner = owner_thread->RemoveWaiterByKey(
std::addressof(num_waiters), reinterpret_cast<uintptr_t>(std::addressof(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);
if (num_waiters > 1) {
next_tag |= 0x1;
}
next_tag =
reinterpret_cast<uintptr_t>(next_owner) | static_cast<uintptr_t>(num_waiters > 1);
next_owner->SetState(ThreadState::Runnable);
next_owner->EndWait(ResultSuccess);
if (next_owner->IsSuspended()) {
next_owner->ContinueIfHasKernelWaiters();
@ -110,7 +111,7 @@ void KLightLock::UnlockSlowPath(uintptr_t _cur_thread) {
}
// Write the new tag value.
tag.store(next_tag);
tag.store(next_tag, std::memory_order_release);
}
}

View file

@ -20,7 +20,7 @@ public:
void Unlock();
void LockSlowPath(uintptr_t owner, uintptr_t cur_thread);
bool LockSlowPath(uintptr_t owner, uintptr_t cur_thread);
void UnlockSlowPath(uintptr_t cur_thread);