From 9c3419ebccf046e0a123e0516ea134547393e451 Mon Sep 17 00:00:00 2001
From: bunnei <bunneidev@gmail.com>
Date: Fri, 3 Apr 2015 18:40:16 -0400
Subject: [PATCH] Kernel: Implemented priority inheritance for mutexes.
---
src/core/hle/kernel/mutex.cpp | 10 +++++++++-
src/core/hle/kernel/thread.cpp | 10 +++++++---
src/core/hle/kernel/thread.h | 6 ++++++
3 files changed, 22 insertions(+), 4 deletions(-)
diff --git a/src/core/hle/kernel/mutex.cpp b/src/core/hle/kernel/mutex.cpp
index be2c49706a..ebc9e79d79 100644
--- a/src/core/hle/kernel/mutex.cpp
+++ b/src/core/hle/kernel/mutex.cpp
@@ -56,7 +56,15 @@ SharedPtr<Mutex> Mutex::Create(bool initial_locked, std::string name) {
}
bool Mutex::ShouldWait() {
- return lock_count > 0 && holding_thread != GetCurrentThread();;
+ auto thread = GetCurrentThread();
+ bool wait = lock_count > 0 && holding_thread != thread;
+
+ // If the holding thread of the mutex is lower priority than this thread, that thread should
+ // temporarily inherit this thread's priority
+ if (wait && thread->current_priority < holding_thread->current_priority)
+ holding_thread->BoostPriority(thread->current_priority);
+
+ return wait;
}
void Mutex::Acquire() {
diff --git a/src/core/hle/kernel/thread.cpp b/src/core/hle/kernel/thread.cpp
index 3a1e15ac67..33d66b9867 100644
--- a/src/core/hle/kernel/thread.cpp
+++ b/src/core/hle/kernel/thread.cpp
@@ -156,9 +156,8 @@ static void PriorityBoostStarvedThreads() {
u64 delta = current_ticks - thread->last_running_ticks;
if (thread->status == THREADSTATUS_READY && delta > boost_timeout && !thread->idle) {
- const s32 boost_priority = std::max(ready_queue.get_first()->current_priority - 1, 0);
- ready_queue.move(thread, thread->current_priority, boost_priority);
- thread->current_priority = boost_priority;
+ const s32 priority = std::max(ready_queue.get_first()->current_priority - 1, 0);
+ thread->BoostPriority(priority);
}
}
}
@@ -435,6 +434,11 @@ void Thread::SetPriority(s32 priority) {
nominal_priority = current_priority = priority;
}
+void Thread::BoostPriority(s32 priority) {
+ ready_queue.move(this, current_priority, priority);
+ current_priority = priority;
+}
+
SharedPtr<Thread> SetupIdleThread() {
// We need to pass a few valid values to get around parameter checking in Thread::Create.
auto thread = Thread::Create("idle", Memory::KERNEL_MEMORY_VADDR, THREADPRIO_LOWEST, 0,
diff --git a/src/core/hle/kernel/thread.h b/src/core/hle/kernel/thread.h
index 92f2c423b0..233bcbdbda 100644
--- a/src/core/hle/kernel/thread.h
+++ b/src/core/hle/kernel/thread.h
@@ -89,6 +89,12 @@ public:
*/
void SetPriority(s32 priority);
+ /**
+ * Temporarily boosts the thread's priority until the next time it is scheduled
+ * @param priority The new priority
+ */
+ void BoostPriority(s32 priority);
+
/**
* Gets the thread's thread ID
* @return The thread's ID
--
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