kernel: Update cpu_ent::active_time atomically

src/system/kernel/cpu.cpp

@@ -74,12 +74,7 @@ cpu_get_active_time(int32 cpu)
 	if (cpu < 0 || cpu > smp_get_num_cpus())
 		return 0;
 
-	// We need to grab the scheduler lock here, because the thread activity
-	// time is not maintained atomically (because there is no need to).
-
-	InterruptsSpinLocker schedulerLocker(gSchedulerLock);
-
-	return gCPU[cpu].active_time;
+	return atomic_get64(&gCPU[cpu].active_time);
 }
 
 

src/system/kernel/scheduler/scheduler_affine.cpp

@@ -1213,7 +1213,7 @@ affine_track_cpu_activity(Thread* oldThread, Thread* nextThread, int32 thisCore)
 			= (oldThread->kernel_time - oldThread->cpu->last_kernel_time)
 				+ (oldThread->user_time - oldThread->cpu->last_user_time);
 
-		oldThread->cpu->active_time += active;
+		atomic_add64(&oldThread->cpu->active_time, active);
 		sCoreEntries[thisCore].fActiveTime += active;
 	}
 

src/system/kernel/scheduler/scheduler_simple.cpp

@@ -634,9 +634,9 @@ simple_reschedule(void)
 
 	// track CPU activity
 	if (!thread_is_idle_thread(oldThread)) {
-		oldThread->cpu->active_time +=
+		atomic_add64(&oldThread->cpu->active_time,
 			(oldThread->kernel_time - oldThread->cpu->last_kernel_time)
-			+ (oldThread->user_time - oldThread->cpu->last_user_time);
+			+ (oldThread->user_time - oldThread->cpu->last_user_time));
 	}
 
 	if (!thread_is_idle_thread(nextThread)) {