Since the waitermutex is only ever locked for a short amount of time, spinning in contention-heavy scenarios ends up quite a bit more efficient than a kernel wait.
This removes the need to concatenate the variable multiple times, recycles the scaled bitmap after it has been stored, addresses the Android Studio complaint about that method name, and generates a preview of the current profile image as the preference icon.
The implementation for this service function wasn't added to the service function table. Additionally, the type for the output `ScalingMode` was implicitly `int` as it was unspecified in the `enum class` which has now been corrected to `u64` as it should be.
Due to broken drivers, it's possible to find no Vulkan physical devices but this can lead to a cryptic segfault. This explicitly checks for it instead and throws an exception which will be emitted into logcat thus can be easily caught.
Due to the trampoline and save/load context functions, `GetHookSectionSize` returned a non-zero size for when there were no hooked symbols supplied to it. This is problematic as it isn't required and hooking is currently not stable so it can lead to crashes or freezes in certain titles.
A thread can be paused while it is in a synchronization primitive which will do `RemoveThread`, we need to update the state of `insertThreadOnResume` in this case by clearing it so it isn't incorrectly reinserted on resuming the thread.
`Scheduler::UpdateCore` implicitly depended on `KThread::coreMigrationMutex` being locked during calls to it, this requirement has now been made explicit to avoid confusion.
When a timeout occurs in `ConditionVariableWait`, we used to check `waitMutex` which is cleared by `MutexUnlock` but when we hit the CAS case in `ConditionVariableSignal` then we don't clear `waitMutex`. It's far more reliable to check `waitThread` as an indication for if the thread has already been unlocked as it's cleared at the start of `ConditionVariableWait` and would implicitly stay cleared in the CAS case while being set in `MutexLock` and being unset in `MutexUnlock`.
There's multiple locations where a thread is yielded in the scheduler and all of them repeat the code of checking for `pendingYield` and signalling with an optional optimization of checking if the thread being yielded is the calling thread.
All this functionality has now been consolidated into `Scheduler::YieldThread` which checks for `pendingYield` and does the calling thread yield optimization. This should lead to better readability and better performance in cases where `UpdatePriority` would signal the calling thread.
`forceYield` was incorrectly not set when pausing running threads if the thread already had `pendingYield` set. This could lead to cases where `Rotate` would later throw an exception due to it being unset.
Blocking while inserting a paused thread can lead to deadlocks where the inserting thread later resumes the paused thread.
Co-authored-by: Billy Laws <blaws05@gmail.com>
As we didn't hold `coreMigrationMutex`, the thread could simply migrate during `InsertThread` which would lead to the thread potentially never waking up as it's been inserted on a non-resident core.
Co-authored-by: PixelyIon <pixelyion@protonmail.com>
`SignalToAddress`/`ConditionVariableSignal` need to wake waiters in priority order, while threads are inserted in order this doesn't remain the case as priority updates don't reinsert the thread into `syncWaiters`.
It was determined that reinsertion into `syncWaiters` would be fairly complex due to locking the `syncWaitersMutex` with the thread's mutexes. To avoid this, this commit instead sorts waiters by priority at signal time to always wake threads in the right order.
Calling `WaitSchedule` inside the block where `syncWaiterMutex` is locked causes a race with other threads which lock the core mutex and `syncWaiterMutex` together. This commit moves the `WaitSchedule` outside the block while simply setting a flag to wait later similar to `ConditionVariableWait`'s timeout case.
Co-authored-by: Billy Laws <blaws05@gmail.com>
This is a cause for a large amount of scheduler bugs so we should generally check for this on debug builds as it is a fairly easy way to check for issues for some performance cost.
The way we handled waking/timeouts of condition variables was fairly inaccurate to HOS as we moved locking of the mutex to the waker thread which could change the order of operations and would cause what were functionally spurious wakeups for all awoken threads.
This commit fixes it by doing all locks on the waker thread and only awakening the waiter thread once the condition variable was signalled and the mutex was unlocked. In addition, this fixes races between a timeout and a signal that could lead to double-insertion as a result of a refactor of how timeouts work in the new system.
`MutexLock` incorrectly returned `InvalidCurrentMemory` for cases where the userspace value didn't match the expected value. It's been corrected to return no error in those cases while preserving the error code for usage in `ConditionalVariableWait`.
We didn't read the values for arbitration atomically in all cases as we should have, this consolidates the reading of the value and uses the value across all cases.
A race could occur from the timeout path in `WaitForAddress` taking place at the same time as `SignalToAddress` has been caused, this causes a deadlock due to double-insertion.
