Kernel/Mutex: Implemented priority inheritance.

The implementation is based on reverse engineering of the 3DS's kernel.

A mutex holder's priority will be temporarily boosted to the best priority among any threads that want to acquire any of its held mutexes.
When the holder releases the mutex, it's priority will be boosted to the best priority among the threads that want to acquire any of its remaining held mutexes.

1 files changed, 0 insertions, 9 deletions

diff --git a/src/core/hle/svc.cpp b/src/core/hle/svc.cpp
index 159ac0bf6..5d6359344 100644
--- a/src/core/hle/svc.cpp
+++ b/src/core/hle/svc.cpp
@@ -278,9 +278,6 @@ static ResultCode WaitSynchronization1(Kernel::Handle handle, s64 nano_seconds)
             return ERR_SYNC_TIMEOUT;
 
         object->AddWaitingThread(thread);
-        // TODO(Subv): Perform things like update the mutex lock owner's priority to
-        // prevent priority inversion. Currently this is done in Mutex::ShouldWait,
-        // but it should be moved to a function that is called from here.
         thread->status = THREADSTATUS_WAIT_SYNCH;
 
         // Create an event to wake the thread up after the specified nanosecond delay has passed
@@ -359,9 +356,6 @@ static ResultCode WaitSynchronizationN(s32* out, Kernel::Handle* handles, s32 ha
         // Add the thread to each of the objects' waiting threads.
         for (auto& object : objects) {
             object->AddWaitingThread(thread);
-            // TODO(Subv): Perform things like update the mutex lock owner's priority to
-            // prevent priority inversion. Currently this is done in Mutex::ShouldWait,
-            // but it should be moved to a function that is called from here.
         }
 
         // Set the thread's waitlist to the list of objects passed to WaitSynchronizationN
@@ -409,9 +403,6 @@ static ResultCode WaitSynchronizationN(s32* out, Kernel::Handle* handles, s32 ha
             // Set the index of this object in the mapping of Objects -> index for this thread.
             thread->wait_objects_index[object->GetObjectId()] = static_cast<int>(i);
             object->AddWaitingThread(thread);
-            // TODO(Subv): Perform things like update the mutex lock owner's priority to
-            // prevent priority inversion. Currently this is done in Mutex::ShouldWait,
-            // but it should be moved to a function that is called from here.
         }
 
         // Note: If no handles and no timeout were given, then the thread will deadlock, this is