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-rw-r--r--src/core/hle/kernel/kernel.h2
-rw-r--r--src/core/hle/kernel/mutex.cpp58
-rw-r--r--src/core/hle/kernel/mutex.h7
-rw-r--r--src/core/hle/kernel/thread.cpp6
-rw-r--r--src/core/hle/svc.cpp9
5 files changed, 51 insertions, 31 deletions
diff --git a/src/core/hle/kernel/kernel.h b/src/core/hle/kernel/kernel.h
index 67eae93f2..2680f89c9 100644
--- a/src/core/hle/kernel/kernel.h
+++ b/src/core/hle/kernel/kernel.h
@@ -145,7 +145,7 @@ public:
* Add a thread to wait on this object
* @param thread Pointer to thread to add
*/
- void AddWaitingThread(SharedPtr<Thread> thread);
+ virtual void AddWaitingThread(SharedPtr<Thread> thread);
/**
* Removes a thread from waiting on this object (e.g. if it was resumed already)
diff --git a/src/core/hle/kernel/mutex.cpp b/src/core/hle/kernel/mutex.cpp
index 072e4e7c1..e83717e80 100644
--- a/src/core/hle/kernel/mutex.cpp
+++ b/src/core/hle/kernel/mutex.cpp
@@ -6,6 +6,7 @@
#include <vector>
#include <boost/range/algorithm_ext/erase.hpp>
#include "common/assert.h"
+#include "core/core.h"
#include "core/hle/kernel/kernel.h"
#include "core/hle/kernel/mutex.h"
#include "core/hle/kernel/thread.h"
@@ -13,19 +14,25 @@
namespace Kernel {
/**
- * Resumes a thread waiting for the specified mutex
- * @param mutex The mutex that some thread is waiting on
+ * Boost's a thread's priority to the best priority among the thread's held mutexes.
+ * This prevents priority inversion via priority inheritance.
*/
-static void ResumeWaitingThread(Mutex* mutex) {
- // Reset mutex lock thread handle, nothing is waiting
- mutex->lock_count = 0;
- mutex->holding_thread = nullptr;
- mutex->WakeupAllWaitingThreads();
+static void UpdateThreadPriority(Thread* thread) {
+ s32 best_priority = THREADPRIO_LOWEST;
+ for (auto& mutex : thread->held_mutexes) {
+ if (mutex->priority < best_priority)
+ best_priority = mutex->priority;
+ }
+
+ best_priority = std::min(best_priority, thread->nominal_priority);
+ thread->SetPriority(best_priority);
}
void ReleaseThreadMutexes(Thread* thread) {
for (auto& mtx : thread->held_mutexes) {
- ResumeWaitingThread(mtx.get());
+ mtx->lock_count = 0;
+ mtx->holding_thread = nullptr;
+ mtx->WakeupAllWaitingThreads();
}
thread->held_mutexes.clear();
}
@@ -54,27 +61,52 @@ bool Mutex::ShouldWait(Thread* thread) const {
void Mutex::Acquire(Thread* thread) {
ASSERT_MSG(!ShouldWait(thread), "object unavailable!");
- // Actually "acquire" the mutex only if we don't already have it...
+ // Actually "acquire" the mutex only if we don't already have it
if (lock_count == 0) {
+ priority = thread->current_priority;
thread->held_mutexes.insert(this);
- holding_thread = std::move(thread);
+ holding_thread = thread;
+
+ UpdateThreadPriority(thread);
+
+ Core::System::GetInstance().PrepareReschedule();
}
lock_count++;
}
void Mutex::Release() {
- // Only release if the mutex is held...
+ // Only release if the mutex is held
if (lock_count > 0) {
lock_count--;
- // Yield to the next thread only if we've fully released the mutex...
+ // Yield to the next thread only if we've fully released the mutex
if (lock_count == 0) {
holding_thread->held_mutexes.erase(this);
- ResumeWaitingThread(this);
+ UpdateThreadPriority(holding_thread.get());
+ holding_thread = nullptr;
+ WakeupAllWaitingThreads();
Core::System::GetInstance().PrepareReschedule();
}
}
}
+void Mutex::AddWaitingThread(SharedPtr<Thread> thread) {
+ WaitObject::AddWaitingThread(thread);
+
+ // Elevate the mutex priority to the best priority
+ // among the priorities of all its waiting threads.
+
+ s32 best_priority = THREADPRIO_LOWEST;
+ for (auto& waiter : GetWaitingThreads()) {
+ if (waiter->current_priority < best_priority)
+ best_priority = waiter->current_priority;
+ }
+
+ if (best_priority != priority) {
+ priority = best_priority;
+ UpdateThreadPriority(holding_thread.get());
+ }
+}
+
} // namespace
diff --git a/src/core/hle/kernel/mutex.h b/src/core/hle/kernel/mutex.h
index 98b3d40b5..3e6adeb17 100644
--- a/src/core/hle/kernel/mutex.h
+++ b/src/core/hle/kernel/mutex.h
@@ -35,18 +35,15 @@ public:
}
int lock_count; ///< Number of times the mutex has been acquired
+ u32 priority; ///< The priority of the mutex, used for priority inheritance.
std::string name; ///< Name of mutex (optional)
SharedPtr<Thread> holding_thread; ///< Thread that has acquired the mutex
bool ShouldWait(Thread* thread) const override;
void Acquire(Thread* thread) override;
+ void AddWaitingThread(SharedPtr<Thread> thread) override;
- /**
- * Acquires the specified mutex for the specified thread
- * @param thread Thread that will acquire the mutex
- */
- void Acquire(SharedPtr<Thread> thread);
void Release();
private:
diff --git a/src/core/hle/kernel/thread.cpp b/src/core/hle/kernel/thread.cpp
index 7d03a2cf7..d44010824 100644
--- a/src/core/hle/kernel/thread.cpp
+++ b/src/core/hle/kernel/thread.cpp
@@ -90,9 +90,6 @@ static bool CheckWait_AddressArbiter(const Thread* thread, VAddr wait_address) {
}
void Thread::Stop() {
- // Release all the mutexes that this thread holds
- ReleaseThreadMutexes(this);
-
// Cancel any outstanding wakeup events for this thread
CoreTiming::UnscheduleEvent(ThreadWakeupEventType, callback_handle);
wakeup_callback_handle_table.Close(callback_handle);
@@ -108,6 +105,9 @@ void Thread::Stop() {
WakeupAllWaitingThreads();
+ // Release all the mutexes that this thread holds
+ ReleaseThreadMutexes(this);
+
// Clean up any dangling references in objects that this thread was waiting for
for (auto& wait_object : wait_objects) {
wait_object->RemoveWaitingThread(this);
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
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-22 23:57:24 +0100