Commit e675447b authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Ingo Molnar
Browse files

timers: Make 'pinned' a timer property 



We want to move the timer migration logic from a 'push' to a 'pull' model.

Under the current 'push' model pinned timers are handled via
a runtime API variant: mod_timer_pinned().

The 'pull' model requires us to store the pinned attribute of a timer
in the timer_list structure itself, as a new TIMER_PINNED bit in
timer->flags.

This flag must be set at initialization time and the timer APIs
recognize the flag.

This patch:

 - Implements the new flag and associated new-style initialization
   methods

 - makes mod_timer() recognize new-style pinned timers,

 - and adds some migration helper facility to allow
   step by step conversion of old-style to new-style
   pinned timers.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Chris Mason <clm@fb.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: George Spelvin <linux@sciencehorizons.net>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Len Brown <lenb@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160704094341.049338558@linutronix.de


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent a99cde43

include/linux/timer.h

+22 −3
Original line number Diff line number Diff line
@@ -62,7 +62,8 @@ struct timer_list { 
#define TIMER_MIGRATING		0x00080000

#define TIMER_BASEMASK		(TIMER_CPUMASK | TIMER_MIGRATING)

#define TIMER_DEFERRABLE	0x00100000

#define TIMER_IRQSAFE		0x00200000

#define TIMER_PINNED		0x00200000

#define TIMER_IRQSAFE		0x00400000



#define __TIMER_INITIALIZER(_function, _expires, _data, _flags) { \

		.entry = { .next = TIMER_ENTRY_STATIC },	\
@@ -78,9 +79,15 @@ struct timer_list { 
#define TIMER_INITIALIZER(_function, _expires, _data)		\

	__TIMER_INITIALIZER((_function), (_expires), (_data), 0)



#define TIMER_PINNED_INITIALIZER(_function, _expires, _data)	\

	__TIMER_INITIALIZER((_function), (_expires), (_data), TIMER_PINNED)



#define TIMER_DEFERRED_INITIALIZER(_function, _expires, _data)	\

	__TIMER_INITIALIZER((_function), (_expires), (_data), TIMER_DEFERRABLE)



#define TIMER_PINNED_DEFERRED_INITIALIZER(_function, _expires, _data)	\

	__TIMER_INITIALIZER((_function), (_expires), (_data), TIMER_DEFERRABLE | TIMER_PINNED)



#define DEFINE_TIMER(_name, _function, _expires, _data)		\

	struct timer_list _name =				\

		TIMER_INITIALIZER(_function, _expires, _data)
@@ -124,8 +131,12 @@ static inline void init_timer_on_stack_key(struct timer_list *timer, 


#define init_timer(timer)						\

	__init_timer((timer), 0)

#define init_timer_pinned(timer)					\

	__init_timer((timer), TIMER_PINNED)

#define init_timer_deferrable(timer)					\

	__init_timer((timer), TIMER_DEFERRABLE)

#define init_timer_pinned_deferrable(timer)				\

	__init_timer((timer), TIMER_DEFERRABLE | TIMER_PINNED)

#define init_timer_on_stack(timer)					\

	__init_timer_on_stack((timer), 0)
@@ -145,12 +156,20 @@ static inline void init_timer_on_stack_key(struct timer_list *timer, 


#define setup_timer(timer, fn, data)					\

	__setup_timer((timer), (fn), (data), 0)

#define setup_pinned_timer(timer, fn, data)				\

	__setup_timer((timer), (fn), (data), TIMER_PINNED)

#define setup_deferrable_timer(timer, fn, data)				\

	__setup_timer((timer), (fn), (data), TIMER_DEFERRABLE)

#define setup_pinned_deferrable_timer(timer, fn, data)			\

	__setup_timer((timer), (fn), (data), TIMER_DEFERRABLE | TIMER_PINNED)

#define setup_timer_on_stack(timer, fn, data)				\

	__setup_timer_on_stack((timer), (fn), (data), 0)

#define setup_pinned_timer_on_stack(timer, fn, data)			\

	__setup_timer_on_stack((timer), (fn), (data), TIMER_PINNED)

#define setup_deferrable_timer_on_stack(timer, fn, data)		\

	__setup_timer_on_stack((timer), (fn), (data), TIMER_DEFERRABLE)

#define setup_pinned_deferrable_timer_on_stack(timer, fn, data)		\

	__setup_timer_on_stack((timer), (fn), (data), TIMER_DEFERRABLE | TIMER_PINNED)



/**

 * timer_pending - is a timer pending?
@@ -175,8 +194,8 @@ extern int mod_timer_pinned(struct timer_list *timer, unsigned long expires); 


extern void set_timer_slack(struct timer_list *time, int slack_hz);



#define TIMER_NOT_PINNED	0

#define TIMER_PINNED		1

#define MOD_TIMER_NOT_PINNED	0

#define MOD_TIMER_PINNED	1

/*

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

 * in the timer wheel:

kernel/time/timer.c

+5 −5
Original line number Diff line number Diff line
@@ -782,7 +782,7 @@ __mod_timer(struct timer_list *timer, unsigned long expires, 


	debug_activate(timer, expires);



	new_base = get_target_base(base, pinned);

	new_base = get_target_base(base, pinned || timer->flags & TIMER_PINNED);



	if (base != new_base) {

		/*
@@ -825,7 +825,7 @@ out_unlock: 
 */

int mod_timer_pending(struct timer_list *timer, unsigned long expires)

{

	return __mod_timer(timer, expires, true, TIMER_NOT_PINNED);

	return __mod_timer(timer, expires, true, MOD_TIMER_NOT_PINNED);

}

EXPORT_SYMBOL(mod_timer_pending);
@@ -900,7 +900,7 @@ int mod_timer(struct timer_list *timer, unsigned long expires) 
	if (timer_pending(timer) && timer->expires == expires)

		return 1;



	return __mod_timer(timer, expires, false, TIMER_NOT_PINNED);

	return __mod_timer(timer, expires, false, MOD_TIMER_NOT_PINNED);

}

EXPORT_SYMBOL(mod_timer);
@@ -928,7 +928,7 @@ int mod_timer_pinned(struct timer_list *timer, unsigned long expires) 
	if (timer->expires == expires && timer_pending(timer))

		return 1;



	return __mod_timer(timer, expires, false, TIMER_PINNED);

	return __mod_timer(timer, expires, false, MOD_TIMER_PINNED);

}

EXPORT_SYMBOL(mod_timer_pinned);
@@ -1512,7 +1512,7 @@ signed long __sched schedule_timeout(signed long timeout) 
	expire = timeout + jiffies;



	setup_timer_on_stack(&timer, process_timeout, (unsigned long)current);

	__mod_timer(&timer, expire, false, TIMER_NOT_PINNED);

	__mod_timer(&timer, expire, false, MOD_TIMER_NOT_PINNED);

	schedule();

	del_singleshot_timer_sync(&timer);

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