3bbb9ec946
While HR timers have had the concept of timer slack for quite some time now, the legacy timers lacked this concept, and had to make do with round_jiffies() and friends. Timer slack is important for power management; grouping timers reduces the number of wakeups which in turn reduces power consumption. This patch introduces timer slack to the legacy timers using the following pieces: * A slack field in the timer struct * An api (set_timer_slack) that callers can use to set explicit timer slack * A default slack of 0.4% of the requested delay for callers that do not set any explicit slack * Rounding code that is part of mod_timer() that tries to group timers around jiffies values every 'power of two' (so quick timers will group around every 2, but longer timers will group around every 4, 8, 16, 32 etc) Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Cc: johnstul@us.ibm.com Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
261 lines
7.2 KiB
C
261 lines
7.2 KiB
C
#ifndef _LINUX_TIMER_H
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#define _LINUX_TIMER_H
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#include <linux/list.h>
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#include <linux/ktime.h>
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#include <linux/stddef.h>
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#include <linux/debugobjects.h>
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#include <linux/stringify.h>
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struct tvec_base;
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struct timer_list {
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/*
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* All fields that change during normal runtime grouped to the
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* same cacheline
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*/
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struct list_head entry;
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unsigned long expires;
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struct tvec_base *base;
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void (*function)(unsigned long);
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unsigned long data;
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int slack;
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#ifdef CONFIG_TIMER_STATS
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void *start_site;
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char start_comm[16];
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int start_pid;
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#endif
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#ifdef CONFIG_LOCKDEP
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struct lockdep_map lockdep_map;
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#endif
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};
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extern struct tvec_base boot_tvec_bases;
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#ifdef CONFIG_LOCKDEP
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/*
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* NB: because we have to copy the lockdep_map, setting the lockdep_map key
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* (second argument) here is required, otherwise it could be initialised to
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* the copy of the lockdep_map later! We use the pointer to and the string
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* "<file>:<line>" as the key resp. the name of the lockdep_map.
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*/
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#define __TIMER_LOCKDEP_MAP_INITIALIZER(_kn) \
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.lockdep_map = STATIC_LOCKDEP_MAP_INIT(_kn, &_kn),
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#else
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#define __TIMER_LOCKDEP_MAP_INITIALIZER(_kn)
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#endif
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#define TIMER_INITIALIZER(_function, _expires, _data) { \
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.entry = { .prev = TIMER_ENTRY_STATIC }, \
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.function = (_function), \
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.expires = (_expires), \
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.data = (_data), \
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.base = &boot_tvec_bases, \
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__TIMER_LOCKDEP_MAP_INITIALIZER( \
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__FILE__ ":" __stringify(__LINE__)) \
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}
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#define DEFINE_TIMER(_name, _function, _expires, _data) \
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struct timer_list _name = \
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TIMER_INITIALIZER(_function, _expires, _data)
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void init_timer_key(struct timer_list *timer,
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const char *name,
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struct lock_class_key *key);
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void init_timer_deferrable_key(struct timer_list *timer,
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const char *name,
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struct lock_class_key *key);
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#ifdef CONFIG_LOCKDEP
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#define init_timer(timer) \
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do { \
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static struct lock_class_key __key; \
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init_timer_key((timer), #timer, &__key); \
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} while (0)
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#define init_timer_deferrable(timer) \
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do { \
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static struct lock_class_key __key; \
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init_timer_deferrable_key((timer), #timer, &__key); \
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} while (0)
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#define init_timer_on_stack(timer) \
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do { \
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static struct lock_class_key __key; \
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init_timer_on_stack_key((timer), #timer, &__key); \
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} while (0)
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#define setup_timer(timer, fn, data) \
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do { \
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static struct lock_class_key __key; \
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setup_timer_key((timer), #timer, &__key, (fn), (data));\
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} while (0)
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#define setup_timer_on_stack(timer, fn, data) \
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do { \
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static struct lock_class_key __key; \
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setup_timer_on_stack_key((timer), #timer, &__key, \
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(fn), (data)); \
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} while (0)
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#else
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#define init_timer(timer)\
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init_timer_key((timer), NULL, NULL)
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#define init_timer_deferrable(timer)\
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init_timer_deferrable_key((timer), NULL, NULL)
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#define init_timer_on_stack(timer)\
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init_timer_on_stack_key((timer), NULL, NULL)
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#define setup_timer(timer, fn, data)\
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setup_timer_key((timer), NULL, NULL, (fn), (data))
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#define setup_timer_on_stack(timer, fn, data)\
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setup_timer_on_stack_key((timer), NULL, NULL, (fn), (data))
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#endif
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#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
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extern void init_timer_on_stack_key(struct timer_list *timer,
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const char *name,
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struct lock_class_key *key);
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extern void destroy_timer_on_stack(struct timer_list *timer);
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#else
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static inline void destroy_timer_on_stack(struct timer_list *timer) { }
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static inline void init_timer_on_stack_key(struct timer_list *timer,
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const char *name,
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struct lock_class_key *key)
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{
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init_timer_key(timer, name, key);
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}
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#endif
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static inline void setup_timer_key(struct timer_list * timer,
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const char *name,
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struct lock_class_key *key,
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void (*function)(unsigned long),
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unsigned long data)
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{
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timer->function = function;
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timer->data = data;
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init_timer_key(timer, name, key);
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}
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static inline void setup_timer_on_stack_key(struct timer_list *timer,
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const char *name,
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struct lock_class_key *key,
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void (*function)(unsigned long),
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unsigned long data)
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{
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timer->function = function;
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timer->data = data;
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init_timer_on_stack_key(timer, name, key);
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}
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/**
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* timer_pending - is a timer pending?
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* @timer: the timer in question
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*
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* timer_pending will tell whether a given timer is currently pending,
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* or not. Callers must ensure serialization wrt. other operations done
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* to this timer, eg. interrupt contexts, or other CPUs on SMP.
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*
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* return value: 1 if the timer is pending, 0 if not.
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*/
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static inline int timer_pending(const struct timer_list * timer)
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{
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return timer->entry.next != NULL;
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}
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extern void add_timer_on(struct timer_list *timer, int cpu);
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extern int del_timer(struct timer_list * timer);
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extern int mod_timer(struct timer_list *timer, unsigned long expires);
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extern int mod_timer_pending(struct timer_list *timer, unsigned long expires);
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extern int mod_timer_pinned(struct timer_list *timer, unsigned long expires);
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extern void set_timer_slack(struct timer_list *time, int slack_hz);
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#define TIMER_NOT_PINNED 0
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#define TIMER_PINNED 1
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/*
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* The jiffies value which is added to now, when there is no timer
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* in the timer wheel:
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*/
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#define NEXT_TIMER_MAX_DELTA ((1UL << 30) - 1)
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/*
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* Return when the next timer-wheel timeout occurs (in absolute jiffies),
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* locks the timer base and does the comparison against the given
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* jiffie.
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*/
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extern unsigned long get_next_timer_interrupt(unsigned long now);
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/*
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* Timer-statistics info:
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*/
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#ifdef CONFIG_TIMER_STATS
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extern int timer_stats_active;
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#define TIMER_STATS_FLAG_DEFERRABLE 0x1
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extern void init_timer_stats(void);
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extern void timer_stats_update_stats(void *timer, pid_t pid, void *startf,
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void *timerf, char *comm,
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unsigned int timer_flag);
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extern void __timer_stats_timer_set_start_info(struct timer_list *timer,
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void *addr);
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static inline void timer_stats_timer_set_start_info(struct timer_list *timer)
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{
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if (likely(!timer_stats_active))
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return;
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__timer_stats_timer_set_start_info(timer, __builtin_return_address(0));
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}
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static inline void timer_stats_timer_clear_start_info(struct timer_list *timer)
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{
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timer->start_site = NULL;
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}
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#else
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static inline void init_timer_stats(void)
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{
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}
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static inline void timer_stats_timer_set_start_info(struct timer_list *timer)
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{
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}
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static inline void timer_stats_timer_clear_start_info(struct timer_list *timer)
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{
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}
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#endif
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extern void add_timer(struct timer_list *timer);
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#ifdef CONFIG_SMP
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extern int try_to_del_timer_sync(struct timer_list *timer);
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extern int del_timer_sync(struct timer_list *timer);
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#else
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# define try_to_del_timer_sync(t) del_timer(t)
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# define del_timer_sync(t) del_timer(t)
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#endif
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#define del_singleshot_timer_sync(t) del_timer_sync(t)
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extern void init_timers(void);
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extern void run_local_timers(void);
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struct hrtimer;
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extern enum hrtimer_restart it_real_fn(struct hrtimer *);
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unsigned long __round_jiffies(unsigned long j, int cpu);
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unsigned long __round_jiffies_relative(unsigned long j, int cpu);
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unsigned long round_jiffies(unsigned long j);
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unsigned long round_jiffies_relative(unsigned long j);
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unsigned long __round_jiffies_up(unsigned long j, int cpu);
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unsigned long __round_jiffies_up_relative(unsigned long j, int cpu);
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unsigned long round_jiffies_up(unsigned long j);
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unsigned long round_jiffies_up_relative(unsigned long j);
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#endif
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