Merge "sched: Add a check for cpu unbound deferrable timers" (28e2a94b) · Commits · e / devices / android_kernel_fairphone_FP5

include/linux/timer.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -161,6 +161,9 @@ extern int del_timer(struct timer_list * timer);
		extern int mod_timer(struct timer_list *timer, unsigned long expires);
		extern int mod_timer_pending(struct timer_list *timer, unsigned long expires);
		extern int timer_reduce(struct timer_list *timer, unsigned long expires);
		#ifdef CONFIG_SMP
		extern bool check_pending_deferrable_timers(int cpu);
		#endif

		/*
		* The jiffies value which is added to now, when there is no timer

kernel/time/tick-sched.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -23,6 +23,7 @@
		#include <linux/module.h>
		#include <linux/irq_work.h>
		#include <linux/posix-timers.h>
		#include <linux/timer.h>
		#include <linux/context_tracking.h>
		#include <linux/mm.h>

		@@ -932,6 +933,11 @@ static void __tick_nohz_idle_stop_tick(struct tick_sched *ts)
		ktime_t expires;
		int cpu = smp_processor_id();

		#ifdef CONFIG_SMP
		if (check_pending_deferrable_timers(cpu))
		raise_softirq_irqoff(TIMER_SOFTIRQ);
		#endif

		/*
		* If tick_nohz_get_sleep_length() ran tick_nohz_next_event(), the
		* tick timer expiration time is known already.

kernel/time/timer.c

+40 −1

Original line number	Diff line number	Diff line
		@@ -207,6 +207,7 @@ struct timer_base {

		static DEFINE_PER_CPU(struct timer_base, timer_bases[NR_BASES]);
		struct timer_base timer_base_deferrable;
		static atomic_t deferrable_pending;

		#ifdef CONFIG_NO_HZ_COMMON

		@@ -1518,6 +1519,31 @@ static u64 cmp_next_hrtimer_event(u64 basem, u64 expires)
		return DIV_ROUND_UP_ULL(nextevt, TICK_NSEC) * TICK_NSEC;
		}


		#ifdef CONFIG_SMP
		/*
		* check_pending_deferrable_timers - Check for unbound deferrable timer expiry
		* @cpu - Current CPU
		*
		* The function checks whether any global deferrable pending timers
		* are exipired or not. This function does not check cpu bounded
		* diferrable pending timers expiry.
		*
		* The function returns true when a cpu unbounded deferrable timer is expired.
		*/
		bool check_pending_deferrable_timers(int cpu)
		{
		if (cpu == tick_do_timer_cpu \|\|
		tick_do_timer_cpu == TICK_DO_TIMER_NONE) {
		if (time_after_eq(jiffies, timer_base_deferrable.clk)
		&& !atomic_cmpxchg(&deferrable_pending, 0, 1)) {
		return true;
		}
		}
		return false;
		}
		#endif

		/**
		* get_next_timer_interrupt - return the time (clock mono) of the next timer
		* @basej: base time jiffies
		@@ -1704,9 +1730,13 @@ static __latent_entropy void run_timer_softirq(struct softirq_action *h)

		__run_timers(base);
		if (IS_ENABLED(CONFIG_NO_HZ_COMMON)) {
		__run_timers(&timer_base_deferrable);
		__run_timers(this_cpu_ptr(&timer_bases[BASE_DEF]));
		}

		if ((atomic_cmpxchg(&deferrable_pending, 1, 0) &&
		tick_do_timer_cpu == TICK_DO_TIMER_NONE) \|\|
		tick_do_timer_cpu == smp_processor_id())
		__run_timers(&timer_base_deferrable);
		}

		/*
		@@ -1942,10 +1972,19 @@ static void __init init_timer_cpu(int cpu)
		}
		}

		static inline void init_timer_deferrable_global(void)
		{
		timer_base_deferrable.cpu = nr_cpu_ids;
		raw_spin_lock_init(&timer_base_deferrable.lock);
		timer_base_deferrable.clk = jiffies;
		}

		static void __init init_timer_cpus(void)
		{
		int cpu;

		init_timer_deferrable_global();

		for_each_possible_cpu(cpu)
		init_timer_cpu(cpu);
		}