sched/idle: Add IAS_SMART_HALT_POLL config for smart halt polling feature

hulk inclusion
category: feature
bugzilla: 176961 https://gitee.com/openeuler/kernel/issues/I4E05T

-------------------

Add IAS_SMART_HALT_POLL config for smart halt polling feature
Signed-off-by: NLi Hua <hucool.lihua@huawei.com>
Reviewed-by: NChen Hui <judy.chenhui@huawei.com>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

include/linux/kernel.h

@@ -555,7 +555,9 @@ extern int sysctl_panic_on_rcu_stall;
 extern int sysctl_panic_on_stackoverflow;
 
 extern bool crash_kexec_post_notifiers;
+#ifdef CONFIG_IAS_SMART_HALT_POLL
 extern unsigned long poll_threshold_ns;
+#endif
 
 
 /*

init/Kconfig

@@ -774,6 +774,14 @@ config GENERIC_SCHED_CLOCK
 
 menu "Scheduler features"
 
+config IAS_SMART_HALT_POLL
+	bool "Enable smart halt poll"
+	default n
+	help
+	  Before entering the real idle, polling for a while. if the current
+	  task is set TIF_NEED_RESCHED during the polling process, it will
+	  immediately break from the polling loop.
+
 config UCLAMP_TASK
 	bool "Enable utilization clamping for RT/FAIR tasks"
 	depends on CPU_FREQ_GOV_SCHEDUTIL

kernel/sched/idle.c

@@ -13,11 +13,13 @@
 /* Linker adds these: start and end of __cpuidle functions */
 extern char __cpuidle_text_start[], __cpuidle_text_end[];
 
+#ifdef CONFIG_IAS_SMART_HALT_POLL
 /*
  * Poll_threshold_ns indicates the maximum polling time before
  * entering real idle.
  */
 unsigned long poll_threshold_ns;
+#endif
 
 /**
  * sched_idle_set_state - Record idle state for the current CPU.
@@ -58,6 +60,7 @@ static int __init cpu_idle_nopoll_setup(char *__unused)
 __setup("hlt", cpu_idle_nopoll_setup);
 #endif
 
+#ifdef CONFIG_IAS_SMART_HALT_POLL
 static void smart_idle_poll(void)
 {
 	unsigned long poll_duration = poll_threshold_ns;
@@ -75,6 +78,7 @@ static void smart_idle_poll(void)
 		cur = ktime_get();
 	} while (ktime_before(cur, stop));
 }
+#endif
 
 static noinline int __cpuidle cpu_idle_poll(void)
 {
@@ -82,7 +86,9 @@ static noinline int __cpuidle cpu_idle_poll(void)
 	stop_critical_timings();
 	rcu_idle_enter();
 	local_irq_enable();
+#ifdef CONFIG_IAS_SMART_HALT_POLL
 	smart_idle_poll();
+#endif
 
 	while (!tif_need_resched() &&
 	       (cpu_idle_force_poll || tick_check_broadcast_expired()))
@@ -286,7 +292,9 @@ static void cpuidle_idle_call(void)
 static void do_idle(void)
 {
 	int cpu = smp_processor_id();
+#ifdef CONFIG_IAS_SMART_HALT_POLL
 	unsigned long idle_poll_flag = poll_threshold_ns;
+#endif
 	/*
 	 * If the arch has a polling bit, we maintain an invariant:
 	 *
@@ -319,11 +327,17 @@ static void do_idle(void)
 		 * broadcast device expired for us, we don't want to go deep
 		 * idle as we know that the IPI is going to arrive right away.
 		 */
+#ifdef CONFIG_IAS_SMART_HALT_POLL
 		if (cpu_idle_force_poll || tick_check_broadcast_expired() ||
 			  idle_poll_flag) {
+#else
+		if (cpu_idle_force_poll || tick_check_broadcast_expired()) {
+#endif
 			tick_nohz_idle_restart_tick();
 			cpu_idle_poll();
+#ifdef CONFIG_IAS_SMART_HALT_POLL
 			idle_poll_flag = 0;
+#endif
 		} else {
 			cpuidle_idle_call();
 		}

kernel/sysctl.c

@@ -1849,6 +1849,7 @@ static struct ctl_table kern_table[] = {
 		.proc_handler	= sysctl_sched_uclamp_handler,
 	},
 #endif
+#ifdef CONFIG_IAS_SMART_HALT_POLL
 	{
 		.procname	= "halt_poll_threshold",
 		.data		= &poll_threshold_ns,
@@ -1856,6 +1857,7 @@ static struct ctl_table kern_table[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_doulongvec_minmax,
 	},
+#endif
 #ifdef CONFIG_SCHED_AUTOGROUP
 	{
 		.procname	= "sched_autogroup_enabled",