sched/balancing: Rename scheduler_tick() => sched_tick()

- Standardize on prefixing scheduler-internal functions defined
  in <linux/sched.h> with sched_*() prefix. scheduler_tick() was
  the only function using the scheduler_ prefix. Harmonize it.

- The other reason to rename it is the NOHZ scheduler tick
  handling functions are already named sched_tick_*().
  Make the 'git grep sched_tick' more meaningful.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Link: https://lore.kernel.org/r/20240308111819.1101550-3-mingo@kernel.org

Documentation/scheduler/sched-domains.rst

@@ -32,13 +32,13 @@ load of each of its member CPUs, and only when the load of a group becomes
 out of balance are tasks moved between groups.
 
 In kernel/sched/core.c, trigger_load_balance() is run periodically on each CPU
-through scheduler_tick(). It raises a softirq after the next regularly scheduled
+through sched_tick(). It raises a softirq after the next regularly scheduled
 rebalancing event for the current runqueue has arrived. The actual load
 balancing workhorse, sched_balance_softirq()->rebalance_domains(), is then run
 in softirq context (SCHED_SOFTIRQ).
 
 The latter function takes two arguments: the runqueue of current CPU and whether
-the CPU was idle at the time the scheduler_tick() happened and iterates over all
+the CPU was idle at the time the sched_tick() happened and iterates over all
 sched domains our CPU is on, starting from its base domain and going up the ->parent
 chain. While doing that, it checks to see if the current domain has exhausted its
 rebalance interval. If so, it runs load_balance() on that domain. It then checks

Documentation/translations/zh_CN/scheduler/sched-domains.rst

@@ -34,12 +34,12 @@ CPU共享。任意两个组的CPU掩码的交集不一定为空，如果是这
 调度域中的负载均衡发生在调度组中。也就是说，每个组被视为一个实体。组的负载被定义为它
 管辖的每个CPU的负载之和。仅当组的负载不均衡后，任务才在组之间发生迁移。
 
-在kernel/sched/core.c中，trigger_load_balance()在每个CPU上通过scheduler_tick()
+在kernel/sched/core.c中，trigger_load_balance()在每个CPU上通过sched_tick()
 周期执行。在当前运行队列下一个定期调度再平衡事件到达后，它引发一个软中断。负载均衡真正
 的工作由sched_balance_softirq()->rebalance_domains()完成，在软中断上下文中执行
 （SCHED_SOFTIRQ）。
 
-后一个函数有两个入参：当前CPU的运行队列、它在scheduler_tick()调用时是否空闲。函数会从
+后一个函数有两个入参：当前CPU的运行队列、它在sched_tick()调用时是否空闲。函数会从
 当前CPU所在的基调度域开始迭代执行，并沿着parent指针链向上进入更高层级的调度域。在迭代
 过程中，函数会检查当前调度域是否已经耗尽了再平衡的时间间隔，如果是，它在该调度域运行
 load_balance()。接下来它检查父调度域（如果存在），再后来父调度域的父调度域，以此类推。

include/linux/sched.h

@@ -301,7 +301,7 @@ enum {
 	TASK_COMM_LEN = 16,
 };
 
-extern void scheduler_tick(void);
+extern void sched_tick(void);
 
 #define	MAX_SCHEDULE_TIMEOUT		LONG_MAX
 

kernel/sched/core.c

@@ -5662,7 +5662,7 @@ static inline u64 cpu_resched_latency(struct rq *rq) { return 0; }
  * This function gets called by the timer code, with HZ frequency.
  * We call it with interrupts disabled.
  */
-void scheduler_tick(void)
+void sched_tick(void)
 {
 	int cpu = smp_processor_id();
 	struct rq *rq = cpu_rq(cpu);
@@ -6585,7 +6585,7 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
  *      paths. For example, see arch/x86/entry_64.S.
  *
  *      To drive preemption between tasks, the scheduler sets the flag in timer
- *      interrupt handler scheduler_tick().
+ *      interrupt handler sched_tick().
  *
  *   3. Wakeups don't really cause entry into schedule(). They add a
  *      task to the run-queue and that's it.

kernel/sched/loadavg.c

@@ -379,7 +379,7 @@ void calc_global_load(void)
 }
 
 /*
- * Called from scheduler_tick() to periodically update this CPU's
+ * Called from sched_tick() to periodically update this CPU's
  * active count.
  */
 void calc_global_load_tick(struct rq *this_rq)

kernel/time/timer.c

@@ -2478,7 +2478,7 @@ void update_process_times(int user_tick)
 	if (in_irq())
 		irq_work_tick();
 #endif
-	scheduler_tick();
+	sched_tick();
 	if (IS_ENABLED(CONFIG_POSIX_TIMERS))
 		run_posix_cpu_timers();
 }

kernel/workqueue.c

@@ -1464,7 +1464,7 @@ void wq_worker_sleeping(struct task_struct *task)
  * wq_worker_tick - a scheduler tick occurred while a kworker is running
  * @task: task currently running
  *
- * Called from scheduler_tick(). We're in the IRQ context and the current
+ * Called from sched_tick(). We're in the IRQ context and the current
  * worker's fields which follow the 'K' locking rule can be accessed safely.
  */
 void wq_worker_tick(struct task_struct *task)

tools/testing/selftests/ftrace/test.d/ftrace/func_set_ftrace_file.tc

@@ -19,7 +19,7 @@ fail() { # mesg
 
 FILTER=set_ftrace_filter
 FUNC1="schedule"
-FUNC2="scheduler_tick"
+FUNC2="sched_tick"
 
 ALL_FUNCS="#### all functions enabled ####"