Merge "timer: make deferrable cpu unbound timers really not bound to a cpu" (a28dc9ed) · Commits · e / devices / samsung / android_kernel_samsung_msm8916

kernel/timer.c

+84 −29

Original line number	Diff line number	Diff line
		@@ -91,6 +91,9 @@ struct tvec_base {
		struct tvec_base boot_tvec_bases;
		EXPORT_SYMBOL(boot_tvec_bases);
		static DEFINE_PER_CPU(struct tvec_base *, tvec_bases) = &boot_tvec_bases;
		#ifdef CONFIG_SMP
		static struct tvec_base *tvec_base_deferral = &boot_tvec_bases;
		#endif

		/* Functions below help us manage 'deferrable' flag */
		static inline unsigned int tbase_get_deferrable(struct tvec_base *base)
		@@ -622,7 +625,14 @@ static inline void debug_assert_init(struct timer_list *timer)
		static void do_init_timer(struct timer_list *timer, unsigned int flags,
		const char name, struct lock_class_key key)
		{
		struct tvec_base *base = __raw_get_cpu_var(tvec_bases);
		struct tvec_base *base;

		#ifdef CONFIG_SMP
		if (flags & TIMER_DEFERRABLE)
		base = tvec_base_deferral;
		else
		#endif
		base = __raw_get_cpu_var(tvec_bases);

		timer->entry.next = NULL;
		timer->base = (void *)((unsigned long)base \| flags);
		@@ -740,6 +750,9 @@ __mod_timer(struct timer_list *timer, unsigned long expires,

		debug_activate(timer, expires);

		#ifdef CONFIG_SMP
		if (base != tvec_base_deferral) {
		#endif
		cpu = smp_processor_id();

		#if defined(CONFIG_NO_HZ_COMMON) && defined(CONFIG_SMP)
		@@ -751,10 +764,10 @@ __mod_timer(struct timer_list *timer, unsigned long expires,
		if (base != new_base) {
		/*
		* We are trying to schedule the timer on the local CPU.
		* However we can't change timer's base while it is running,
		* otherwise del_timer_sync() can't detect that the timer's
		* handler yet has not finished. This also guarantees that
		* the timer is serialized wrt itself.
		* However we can't change timer's base while it is
		* running, otherwise del_timer_sync() can't detect that
		* the timer's * handler yet has not finished. This also
		* guarantees that * the timer is serialized wrt itself.
		*/
		if (likely(base->running_timer != timer)) {
		/* See the comment in lock_timer_base() */
		@@ -765,6 +778,9 @@ __mod_timer(struct timer_list *timer, unsigned long expires,
		timer_set_base(timer, base);
		}
		}
		#ifdef CONFIG_SMP
		}
		#endif

		timer->expires = expires;
		internal_add_timer(base, timer);
		@@ -1138,15 +1154,20 @@ static void call_timer_fn(struct timer_list timer, void (fn)(unsigned long),
		/**
		* __run_timers - run all expired timers (if any) on this CPU.
		* @base: the timer vector to be processed.
		* @try: try and just return if base's lock already acquired.
		*
		* This function cascades all vectors and executes all expired timer
		* vectors.
		*/
		static inline void __run_timers(struct tvec_base *base)
		static inline void __run_timers(struct tvec_base *base, bool try)
		{
		struct timer_list *timer;

		if (!try)
		spin_lock_irq(&base->lock);
		else if (!spin_trylock_irq(&base->lock))
		return;

		while (time_after_eq(jiffies, base->timer_jiffies)) {
		struct list_head work_list;
		struct list_head *head = &work_list;
		@@ -1373,8 +1394,17 @@ static void run_timer_softirq(struct softirq_action *h)

		hrtimer_run_pending();

		#ifdef CONFIG_SMP
		if (time_after_eq(jiffies, tvec_base_deferral->timer_jiffies))
		/*
		* if other cpu is handling cpu unbound deferrable timer base,
		* current cpu doesn't need to handle it so pass try=true.
		*/
		__run_timers(tvec_base_deferral, true);
		#endif

		if (time_after_eq(jiffies, base->timer_jiffies))
		__run_timers(base);
		__run_timers(base, false);
		}

		/*
		@@ -1510,7 +1540,7 @@ static int __cpuinit init_timers_cpu(int cpu)
		{
		int j;
		struct tvec_base *base;
		static char __cpuinitdata tvec_base_done[NR_CPUS];
		static char __cpuinitdata tvec_base_done[NR_CPUS + 1];

		if (!tvec_base_done[cpu]) {
		static char boot_done;
		@@ -1519,9 +1549,14 @@ static int __cpuinit init_timers_cpu(int cpu)
		/*
		* The APs use this path later in boot
		*/
		if (cpu != NR_CPUS)
		base = kmalloc_node(sizeof(*base),
		GFP_KERNEL \| __GFP_ZERO,
		cpu_to_node(cpu));
		else
		base = kmalloc(sizeof(*base),
		GFP_KERNEL \| __GFP_ZERO);

		if (!base)
		return -ENOMEM;

		@@ -1531,7 +1566,12 @@ static int __cpuinit init_timers_cpu(int cpu)
		kfree(base);
		return -ENOMEM;
		}
		if (cpu != NR_CPUS)
		per_cpu(tvec_bases, cpu) = base;
		#ifdef CONFIG_SMP
		else
		tvec_base_deferral = base;
		#endif
		} else {
		/*
		* This is for the boot CPU - we use compile-time
		@@ -1545,7 +1585,12 @@ static int __cpuinit init_timers_cpu(int cpu)
		spin_lock_init(&base->lock);
		tvec_base_done[cpu] = 1;
		} else {
		if (cpu != NR_CPUS)
		base = per_cpu(tvec_bases, cpu);
		#ifdef CONFIG_SMP
		else
		base = tvec_base_deferral;
		#endif
		}


		@@ -1653,6 +1698,16 @@ void __init init_timers(void)
		init_timer_stats();

		BUG_ON(err != NOTIFY_OK);

		#ifdef CONFIG_SMP
		/*
		* initialize cpu unbound deferrable timer base only when CONFIG_SMP.
		* UP kernel handles the timers with cpu 0 timer base.
		*/
		err = init_timers_cpu(NR_CPUS);
		BUG_ON(err);
		#endif

		register_cpu_notifier(&timers_nb);
		open_softirq(TIMER_SOFTIRQ, run_timer_softirq);
		}