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-rw-r--r--kernel/time/hrtimer.c17
-rw-r--r--kernel/time/tick-internal.h19
-rw-r--r--kernel/time/tick-sched.c2
-rw-r--r--kernel/time/timer.c83
4 files changed, 60 insertions, 61 deletions
diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index d32520840fde..1d06d2bde733 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -178,23 +178,16 @@ hrtimer_check_target(struct hrtimer *timer, struct hrtimer_clock_base *new_base)
 #endif
 }
 
-#ifdef CONFIG_NO_HZ_COMMON
-static inline
-struct hrtimer_cpu_base *get_target_base(struct hrtimer_cpu_base *base,
-					 int pinned)
-{
-	if (pinned || !base->migration_enabled)
-		return base;
-	return &per_cpu(hrtimer_bases, get_nohz_timer_target());
-}
-#else
 static inline
 struct hrtimer_cpu_base *get_target_base(struct hrtimer_cpu_base *base,
 					 int pinned)
 {
+#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
+	if (static_branch_likely(&timers_migration_enabled) && !pinned)
+		return &per_cpu(hrtimer_bases, get_nohz_timer_target());
+#endif
 	return base;
 }
-#endif
 
 /*
  * We switch the timer base to a power-optimized selected CPU target,
@@ -969,7 +962,7 @@ void hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
 		 * Kick to reschedule the next tick to handle the new timer
 		 * on dynticks target.
 		 */
-		if (new_base->cpu_base->nohz_active)
+		if (is_timers_nohz_active())
 			wake_up_nohz_cpu(new_base->cpu_base->cpu);
 	} else {
 		hrtimer_reprogram(timer, new_base);
diff --git a/kernel/time/tick-internal.h b/kernel/time/tick-internal.h
index f8e1845aa464..f690628e068c 100644
--- a/kernel/time/tick-internal.h
+++ b/kernel/time/tick-internal.h
@@ -150,14 +150,19 @@ static inline void tick_nohz_init(void) { }
 
 #ifdef CONFIG_NO_HZ_COMMON
 extern unsigned long tick_nohz_active;
-#else
+extern void timers_update_nohz(void);
+extern struct static_key_false timers_nohz_active;
+static inline bool is_timers_nohz_active(void)
+{
+	return static_branch_likely(&timers_nohz_active);
+}
+# ifdef CONFIG_SMP
+extern struct static_key_false timers_migration_enabled;
+# endif
+#else /* CONFIG_NO_HZ_COMMON */
+static inline void timers_update_nohz(void) { }
 #define tick_nohz_active (0)
-#endif
-
-#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
-extern void timers_update_migration(bool update_nohz);
-#else
-static inline void timers_update_migration(bool update_nohz) { }
+static inline bool is_timers_nohz_active(void) { return false; }
 #endif
 
 DECLARE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases);
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index f7cc7abfcf25..29a5733eff83 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -1107,7 +1107,7 @@ static inline void tick_nohz_activate(struct tick_sched *ts, int mode)
 	ts->nohz_mode = mode;
 	/* One update is enough */
 	if (!test_and_set_bit(0, &tick_nohz_active))
-		timers_update_migration(true);
+		timers_update_nohz();
 }
 
 /**
diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index 0bcf00e3ce48..d530f72b32f9 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -200,8 +200,6 @@ struct timer_base {
 	unsigned long		clk;
 	unsigned long		next_expiry;
 	unsigned int		cpu;
-	bool			migration_enabled;
-	bool			nohz_active;
 	bool			is_idle;
 	bool			must_forward_clk;
 	DECLARE_BITMAP(pending_map, WHEEL_SIZE);
@@ -210,45 +208,57 @@ struct timer_base {
 
 static DEFINE_PER_CPU(struct timer_base, timer_bases[NR_BASES]);
 
-#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
+#ifdef CONFIG_NO_HZ_COMMON
+
+DEFINE_STATIC_KEY_FALSE(timers_nohz_active);
+static DEFINE_MUTEX(timer_keys_mutex);
+
+static void timer_update_keys(struct work_struct *work);
+static DECLARE_WORK(timer_update_work, timer_update_keys);
+
+#ifdef CONFIG_SMP
 unsigned int sysctl_timer_migration = 1;
 
-void timers_update_migration(bool update_nohz)
+DEFINE_STATIC_KEY_FALSE(timers_migration_enabled);
+
+static void timers_update_migration(void)
 {
-	bool on = sysctl_timer_migration && tick_nohz_active;
-	unsigned int cpu;
+	if (sysctl_timer_migration && tick_nohz_active)
+		static_branch_enable(&timers_migration_enabled);
+	else
+		static_branch_disable(&timers_migration_enabled);
+}
+#else
+static inline void timers_update_migration(void) { }
+#endif /* !CONFIG_SMP */
 
-	/* Avoid the loop, if nothing to update */
-	if (this_cpu_read(timer_bases[BASE_STD].migration_enabled) == on)
-		return;
+static void timer_update_keys(struct work_struct *work)
+{
+	mutex_lock(&timer_keys_mutex);
+	timers_update_migration();
+	static_branch_enable(&timers_nohz_active);
+	mutex_unlock(&timer_keys_mutex);
+}
 
-	for_each_possible_cpu(cpu) {
-		per_cpu(timer_bases[BASE_STD].migration_enabled, cpu) = on;
-		per_cpu(timer_bases[BASE_DEF].migration_enabled, cpu) = on;
-		per_cpu(hrtimer_bases.migration_enabled, cpu) = on;
-		if (!update_nohz)
-			continue;
-		per_cpu(timer_bases[BASE_STD].nohz_active, cpu) = true;
-		per_cpu(timer_bases[BASE_DEF].nohz_active, cpu) = true;
-		per_cpu(hrtimer_bases.nohz_active, cpu) = true;
-	}
+void timers_update_nohz(void)
+{
+	schedule_work(&timer_update_work);
 }
 
 int timer_migration_handler(struct ctl_table *table, int write,
 			    void __user *buffer, size_t *lenp,
 			    loff_t *ppos)
 {
-	static DEFINE_MUTEX(mutex);
 	int ret;
 
-	mutex_lock(&mutex);
+	mutex_lock(&timer_keys_mutex);
 	ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
 	if (!ret && write)
-		timers_update_migration(false);
-	mutex_unlock(&mutex);
+		timers_update_migration();
+	mutex_unlock(&timer_keys_mutex);
 	return ret;
 }
-#endif
+#endif /* NO_HZ_COMMON */
 
 static unsigned long round_jiffies_common(unsigned long j, int cpu,
 		bool force_up)
@@ -534,7 +544,7 @@ __internal_add_timer(struct timer_base *base, struct timer_list *timer)
 static void
 trigger_dyntick_cpu(struct timer_base *base, struct timer_list *timer)
 {
-	if (!IS_ENABLED(CONFIG_NO_HZ_COMMON) || !base->nohz_active)
+	if (!is_timers_nohz_active())
 		return;
 
 	/*
@@ -849,21 +859,20 @@ static inline struct timer_base *get_timer_base(u32 tflags)
 	return get_timer_cpu_base(tflags, tflags & TIMER_CPUMASK);
 }
 
-#ifdef CONFIG_NO_HZ_COMMON
 static inline struct timer_base *
 get_target_base(struct timer_base *base, unsigned tflags)
 {
-#ifdef CONFIG_SMP
-	if ((tflags & TIMER_PINNED) || !base->migration_enabled)
-		return get_timer_this_cpu_base(tflags);
-	return get_timer_cpu_base(tflags, get_nohz_timer_target());
-#else
-	return get_timer_this_cpu_base(tflags);
+#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
+	if (static_branch_likely(&timers_migration_enabled) &&
+	    !(tflags & TIMER_PINNED))
+		return get_timer_cpu_base(tflags, get_nohz_timer_target());
 #endif
+	return get_timer_this_cpu_base(tflags);
 }
 
 static inline void forward_timer_base(struct timer_base *base)
 {
+#ifdef CONFIG_NO_HZ_COMMON
 	unsigned long jnow;
 
 	/*
@@ -887,16 +896,8 @@ static inline void forward_timer_base(struct timer_base *base)
 		base->clk = jnow;
 	else
 		base->clk = base->next_expiry;
-}
-#else
-static inline struct timer_base *
-get_target_base(struct timer_base *base, unsigned tflags)
-{
-	return get_timer_this_cpu_base(tflags);
-}
-
-static inline void forward_timer_base(struct timer_base *base) { }
 #endif
+}
 
 
 /*
generated by cgit-pink 1.4.1 (git 2.36.1) at 2024-10-07 05:28:53 +0000