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Commit c1f109ce authored by Kyle Yan's avatar Kyle Yan
Browse files

timer: Add a global deferrable timer 



Add a global deferrable timer in addition to the per-cpu deferrable timer
to allow deferrable timers without the TIMER_PINNED flag to run
on any active CPU.

Change-Id: I8e6b77cef972589912ad18f324c46c936fbbb96f
Signed-off-by: default avatarKyle Yan <kyan@codeaurora.org>
parent e713c9df

include/linux/timer.h

+2 −0
Original line number Diff line number Diff line
@@ -244,6 +244,8 @@ extern void add_timer(struct timer_list *timer); 


extern int try_to_del_timer_sync(struct timer_list *timer);



extern struct timer_base timer_base_deferrable;



#ifdef CONFIG_SMP

  extern int del_timer_sync(struct timer_list *timer);

#else

kernel/time/timer.c

+15 −4
Original line number Diff line number Diff line
@@ -206,6 +206,7 @@ struct timer_base { 
} ____cacheline_aligned;



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

struct timer_base timer_base_deferrable;



#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)

unsigned int sysctl_timer_migration = 1;
@@ -229,6 +230,9 @@ void timers_update_migration(bool update_nohz) 
		per_cpu(timer_bases[BASE_DEF].nohz_active, cpu) = true;

		per_cpu(hrtimer_bases.nohz_active, cpu) = true;

	}



	timer_base_deferrable.migration_enabled = on;

	timer_base_deferrable.nohz_active = true;

}



int timer_migration_handler(struct ctl_table *table, int write,
@@ -852,8 +856,11 @@ static inline struct timer_base *get_timer_cpu_base(u32 tflags, u32 cpu) 
	 * the deferrable base.

	 */

	if (IS_ENABLED(CONFIG_NO_HZ_COMMON) && base->nohz_active &&

	    (tflags & TIMER_DEFERRABLE))

	    (tflags & TIMER_DEFERRABLE)) {

		base = &timer_base_deferrable;

		if (tflags & TIMER_PINNED)

			base = per_cpu_ptr(&timer_bases[BASE_DEF], cpu);

	}

	return base;

}
@@ -867,6 +874,8 @@ static inline struct timer_base *get_timer_this_cpu_base(u32 tflags) 
	 */

	if (IS_ENABLED(CONFIG_NO_HZ_COMMON) && base->nohz_active &&

	    (tflags & TIMER_DEFERRABLE))

		base = &timer_base_deferrable;

		if (tflags & TIMER_PINNED)

			base = this_cpu_ptr(&timer_bases[BASE_DEF]);

	return base;

}
@@ -1652,9 +1661,11 @@ static __latent_entropy void run_timer_softirq(struct softirq_action *h) 
	struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]);



	__run_timers(base);

	if (IS_ENABLED(CONFIG_NO_HZ_COMMON) && base->nohz_active)

	if (IS_ENABLED(CONFIG_NO_HZ_COMMON) && base->nohz_active) {

		__run_timers(&timer_base_deferrable);

		__run_timers(this_cpu_ptr(&timer_bases[BASE_DEF]));

	}

}



/*

 * Called by the local, per-CPU timer interrupt on SMP.