Kernel: Don't lock scheduler while updating thread scheduling times

We can use simple atomic variables with relaxed ordering for this,
and avoid locking altogether.

2 files changed, 5 insertions, 6 deletions

diff --git a/Kernel/Thread.cpp b/Kernel/Thread.cpp
index 0198c65fce..f787e55881 100644
--- a/Kernel/Thread.cpp
+++ b/Kernel/Thread.cpp
@@ -667,8 +667,7 @@ void Thread::update_time_scheduled(u64 current_scheduler_time, bool is_kernel, b
             Scheduler::add_time_scheduled(delta, is_kernel);
 
             auto& total_time = is_kernel ? m_total_time_scheduled_kernel : m_total_time_scheduled_user;
-            SpinlockLocker scheduler_lock(g_scheduler_lock);
-            total_time += delta;
+            total_time.fetch_add(delta, AK::memory_order_relaxed);
         }
     }
     if (no_longer_running)
diff --git a/Kernel/Thread.h b/Kernel/Thread.h
index c34630020c..09a6f2f6b4 100644
--- a/Kernel/Thread.h
+++ b/Kernel/Thread.h
@@ -1062,8 +1062,8 @@ public:
     static constexpr u32 default_kernel_stack_size = 65536;
     static constexpr u32 default_userspace_stack_size = 1 * MiB;
 
-    u64 time_in_user() const { return m_total_time_scheduled_user; }
-    u64 time_in_kernel() const { return m_total_time_scheduled_kernel; }
+    u64 time_in_user() const { return m_total_time_scheduled_user.load(AK::MemoryOrder::memory_order_relaxed); }
+    u64 time_in_kernel() const { return m_total_time_scheduled_kernel.load(AK::MemoryOrder::memory_order_relaxed); }
 
     enum class PreviousMode : u8 {
         KernelMode = 0,
@@ -1238,8 +1238,8 @@ private:
     Atomic<u32> m_cpu { 0 };
     u32 m_cpu_affinity { THREAD_AFFINITY_DEFAULT };
     Optional<u64> m_last_time_scheduled;
-    u64 m_total_time_scheduled_user { 0 };
-    u64 m_total_time_scheduled_kernel { 0 };
+    Atomic<u64> m_total_time_scheduled_user { 0 };
+    Atomic<u64> m_total_time_scheduled_kernel { 0 };
     u32 m_ticks_left { 0 };
     u32 m_times_scheduled { 0 };
     u32 m_ticks_in_user { 0 };