Merge: sched: tick and timer updates and fixes

MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-9/-/merge_requests/4112

JIRA: https://issues.redhat.com/browse/RHEL-33787  
  
Series and prerequisites from v6.8 to update and  
provide some fixes for scheduler tick and timer  
related code. This addresses some false positive  
softirq pending traces and some potential nohz_full   
tick issues.  
  
  
  
  
  
Signed-off-by: Phil Auld <pauld@redhat.com>

Approved-by: Tony Camuso <tcamuso@redhat.com>
Approved-by: Waiman Long <longman@redhat.com>
Approved-by: CKI KWF Bot <cki-ci-bot+kwf-gitlab-com@redhat.com>

Merged-by: Lucas Zampieri <lzampier@redhat.com>

Author: zampierilucas

MAINTAINERS

@@ -13693,7 +13693,7 @@ F:	include/uapi/linux/nitro_enclaves.h
 F:	samples/nitro_enclaves/
 
 NOHZ, DYNTICKS SUPPORT
-M:	Frederic Weisbecker <fweisbec@gmail.com>
+M:	Frederic Weisbecker <frederic@kernel.org>
 M:	Thomas Gleixner <tglx@linutronix.de>
 M:	Ingo Molnar <mingo@kernel.org>
 L:	linux-kernel@vger.kernel.org

drivers/base/cpu.c

@@ -506,7 +506,8 @@ static const struct attribute_group *cpu_root_attr_groups[] = {
 bool cpu_is_hotpluggable(unsigned int cpu)
 {
 	struct device *dev = get_cpu_device(cpu);
-	return dev && container_of(dev, struct cpu, dev)->hotpluggable;
+	return dev && container_of(dev, struct cpu, dev)->hotpluggable
+		&& tick_nohz_cpu_hotpluggable(cpu);
 }
 EXPORT_SYMBOL_GPL(cpu_is_hotpluggable);
 

include/linux/tick.h

@@ -206,6 +206,7 @@ extern void tick_nohz_dep_set_signal(struct task_struct *tsk,
 				     enum tick_dep_bits bit);
 extern void tick_nohz_dep_clear_signal(struct signal_struct *signal,
 				       enum tick_dep_bits bit);
+extern bool tick_nohz_cpu_hotpluggable(unsigned int cpu);
 
 /*
  * The below are tick_nohz_[set,clear]_dep() wrappers that optimize off-cases
@@ -270,6 +271,7 @@ static inline void tick_nohz_full_add_cpus_to(struct cpumask *mask) { }
 
 static inline void tick_nohz_dep_set_cpu(int cpu, enum tick_dep_bits bit) { }
 static inline void tick_nohz_dep_clear_cpu(int cpu, enum tick_dep_bits bit) { }
+static inline bool tick_nohz_cpu_hotpluggable(unsigned int cpu) { return true; }
 
 static inline void tick_dep_set(enum tick_dep_bits bit) { }
 static inline void tick_dep_clear(enum tick_dep_bits bit) { }

include/trace/events/timer.h

@@ -46,44 +46,46 @@ DEFINE_EVENT(timer_class, timer_init,
 
 /**
  * timer_start - called when the timer is started
- * @timer:	pointer to struct timer_list
- * @expires:	the timers expiry time
+ * @timer:		pointer to struct timer_list
+ * @bucket_expiry:	the bucket expiry time
  */
 TRACE_EVENT(timer_start,
 
 	TP_PROTO(struct timer_list *timer,
-		unsigned long expires,
-		unsigned int flags),
+		unsigned long bucket_expiry),
 
-	TP_ARGS(timer, expires, flags),
+	TP_ARGS(timer, bucket_expiry),
 
 	TP_STRUCT__entry(
 		__field( void *,	timer		)
 		__field( void *,	function	)
 		__field( unsigned long,	expires		)
+		__field( unsigned long,	bucket_expiry	)
 		__field( unsigned long,	now		)
 		__field( unsigned int,	flags		)
 	),
 
 	TP_fast_assign(
 		__entry->timer		= timer;
 		__entry->function	= timer->function;
-		__entry->expires	= expires;
+		__entry->expires	= timer->expires;
+		__entry->bucket_expiry	= bucket_expiry;
 		__entry->now		= jiffies;
-		__entry->flags		= flags;
+		__entry->flags		= timer->flags;
 	),
 
-	TP_printk("timer=%p function=%ps expires=%lu [timeout=%ld] cpu=%u idx=%u flags=%s",
+	TP_printk("timer=%p function=%ps expires=%lu [timeout=%ld] bucket_expiry=%lu cpu=%u idx=%u flags=%s",
 		  __entry->timer, __entry->function, __entry->expires,
 		  (long)__entry->expires - __entry->now,
-		  __entry->flags & TIMER_CPUMASK,
+		  __entry->bucket_expiry, __entry->flags & TIMER_CPUMASK,
 		  __entry->flags >> TIMER_ARRAYSHIFT,
 		  decode_timer_flags(__entry->flags & TIMER_TRACE_FLAGMASK))
 );
 
 /**
  * timer_expire_entry - called immediately before the timer callback
  * @timer:	pointer to struct timer_list
+ * @baseclk:	value of timer_base::clk when timer expires
  *
  * Allows to determine the timer latency.
  */
@@ -140,6 +142,26 @@ DEFINE_EVENT(timer_class, timer_cancel,
 	TP_ARGS(timer)
 );
 
+TRACE_EVENT(timer_base_idle,
+
+	TP_PROTO(bool is_idle, unsigned int cpu),
+
+	TP_ARGS(is_idle, cpu),
+
+	TP_STRUCT__entry(
+		__field( bool,		is_idle	)
+		__field( unsigned int,	cpu	)
+	),
+
+	TP_fast_assign(
+		__entry->is_idle	= is_idle;
+		__entry->cpu		= cpu;
+	),
+
+	TP_printk("is_idle=%d cpu=%d",
+		  __entry->is_idle, __entry->cpu)
+);
+
 #define decode_clockid(type)						\
 	__print_symbolic(type,						\
 		{ CLOCK_REALTIME,	"CLOCK_REALTIME"	},	\
@@ -190,7 +212,8 @@ TRACE_EVENT(hrtimer_init,
 
 /**
  * hrtimer_start - called when the hrtimer is started
- * @hrtimer: pointer to struct hrtimer
+ * @hrtimer:	pointer to struct hrtimer
+ * @mode:	the hrtimers mode
  */
 TRACE_EVENT(hrtimer_start,
 

kernel/time/tick-common.c

@@ -219,7 +219,6 @@ static void tick_setup_device(struct tick_device *td,
 		 */
 		if (tick_do_timer_cpu == TICK_DO_TIMER_BOOT) {
 			tick_do_timer_cpu = cpu;
-
 			tick_next_period = ktime_get();
 #ifdef CONFIG_NO_HZ_FULL
 			/*