sched/alt: Fix build fail with CONFIG_SMP=n

Fix uniprocessor build issue torvalds#101

Author: cchalpha

kernel/sched/alt_core.c

@@ -4172,6 +4172,8 @@ void scheduler_tick(void)
 		wq_worker_tick(curr);
 }
 
+#ifdef CONFIG_SMP
+
 static int active_balance_cpu_stop(void *data)
 {
 	struct balance_arg *arg = data;
@@ -4264,6 +4266,8 @@ static DEFINE_PER_CPU(struct balance_callback, sg_balance_head) = {
 };
 #endif /* CONFIG_SCHED_SMT */
 
+#endif /* CONFIG_SMP */
+
 #ifdef CONFIG_NO_HZ_FULL
 
 struct tick_work {
@@ -7667,7 +7671,9 @@ void __init sched_init(void)
 {
 	int i;
 	struct rq *rq;
+#ifdef CONFIG_SCHED_SMT
 	struct balance_arg balance_arg = {.cpumask = sched_sg_idle_mask, .active = 0};
+#endif
 
 	printk(KERN_INFO "sched/alt: "ALT_SCHED_NAME" CPU Scheduler "ALT_SCHED_VERSION\
 			 " by Alfred Chen.\n");

kernel/sched/alt_sched.h

@@ -351,10 +351,6 @@ static inline int best_mask_cpu(int cpu, const cpumask_t *mask)
 	return __best_mask_cpu(mask, per_cpu(sched_cpu_topo_masks, cpu));
 }
 
-extern void flush_smp_call_function_queue(void);
-
-#else  /* !CONFIG_SMP */
-static inline void flush_smp_call_function_queue(void) { }
 #endif
 
 #ifndef arch_scale_freq_tick