mirror of
https://github.com/Atmosphere-NX/Atmosphere
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63 lines
2.1 KiB
C++
63 lines
2.1 KiB
C++
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#include <mesosphere/threading/KMutex.hpp>
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#include <mesosphere/threading/KThread.hpp>
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#include <mesosphere/threading/KScheduler.hpp>
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namespace mesosphere
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{
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void KMutex::lock_slow_path(KThread &owner, KThread &requester)
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{
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// Requester is currentThread most of (all ?) the time
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KCriticalSection &critsec = KScheduler::GetCriticalSection();
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std::lock_guard criticalSection{critsec};
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if (KCoreContext::GetCurrentInstance().GetScheduler()->IsActive()) {
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requester.SetWantedMutex((uiptr)this);
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owner.AddMutexWaiter(requester);
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// If the requester is/was running, pause it (sets status even if force-paused).
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requester.RescheduleIfStatusEquals(KThread::SchedulingStatus::Running, KThread::SchedulingStatus::Paused);
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// If the owner is force-paused, temporarily wake it.
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if (owner.IsForcePaused()) {
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owner.AdjustScheduling(owner.RevertForcePauseToField());
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}
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// Commit scheduler changes NOW.
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critsec.unlock();
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critsec.lock();
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/*
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At this point, mutex ownership has been transferred to requester or another thread (false wake).
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Make sure the requester, now resumed, isn't in any mutex wait list.
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*/
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owner.RemoveMutexWaiter(requester);
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}
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}
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void KMutex::unlock_slow_path(KThread &owner)
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{
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std::lock_guard criticalSection{KScheduler::GetCriticalSection()};
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size_t count;
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KThread *newOwner = owner.RelinquishMutex(&count, (uiptr)this);
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native_handle_type newTag;
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if (newOwner != nullptr) {
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// Wake up new owner
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newTag = (native_handle_type)newOwner | (count > 1 ? 1 : 0);
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// Sets status even if force-paused.
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newOwner->RescheduleIfStatusEquals(KThread::SchedulingStatus::Paused, KThread::SchedulingStatus::Running);
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} else {
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// Free the mutex.
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newTag = 0;
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}
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// Allow previous owner to get back to forced-sleep, if no other thread wants the kmutexes it is holding.
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if (!owner.IsDying() && owner.GetNumberOfKMutexWaiters() == 0) {
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owner.AdjustScheduling(owner.CommitForcePauseToField());
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}
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tag = newTag;
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}
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}
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