linux/include/linux/timer.h
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   1#ifndef _LINUX_TIMER_H
   2#define _LINUX_TIMER_H
   3
   4#include <linux/list.h>
   5#include <linux/ktime.h>
   6#include <linux/stddef.h>
   7#include <linux/debugobjects.h>
   8#include <linux/stringify.h>
   9
  10struct tvec_base;
  11
  12struct timer_list {
  13        /*
  14         * All fields that change during normal runtime grouped to the
  15         * same cacheline
  16         */
  17        struct list_head entry;
  18        unsigned long expires;
  19        struct tvec_base *base;
  20
  21        void (*function)(unsigned long);
  22        unsigned long data;
  23
  24        int slack;
  25
  26#ifdef CONFIG_TIMER_STATS
  27        int start_pid;
  28        void *start_site;
  29        char start_comm[16];
  30#endif
  31#ifdef CONFIG_LOCKDEP
  32        struct lockdep_map lockdep_map;
  33#endif
  34};
  35
  36extern struct tvec_base boot_tvec_bases;
  37
  38#ifdef CONFIG_LOCKDEP
  39/*
  40 * NB: because we have to copy the lockdep_map, setting the lockdep_map key
  41 * (second argument) here is required, otherwise it could be initialised to
  42 * the copy of the lockdep_map later! We use the pointer to and the string
  43 * "<file>:<line>" as the key resp. the name of the lockdep_map.
  44 */
  45#define __TIMER_LOCKDEP_MAP_INITIALIZER(_kn)                            \
  46        .lockdep_map = STATIC_LOCKDEP_MAP_INIT(_kn, &_kn),
  47#else
  48#define __TIMER_LOCKDEP_MAP_INITIALIZER(_kn)
  49#endif
  50
  51/*
  52 * Note that all tvec_bases are at least 4 byte aligned and lower two bits
  53 * of base in timer_list is guaranteed to be zero. Use them for flags.
  54 *
  55 * A deferrable timer will work normally when the system is busy, but
  56 * will not cause a CPU to come out of idle just to service it; instead,
  57 * the timer will be serviced when the CPU eventually wakes up with a
  58 * subsequent non-deferrable timer.
  59 *
  60 * An irqsafe timer is executed with IRQ disabled and it's safe to wait for
  61 * the completion of the running instance from IRQ handlers, for example,
  62 * by calling del_timer_sync().
  63 *
  64 * Note: The irq disabled callback execution is a special case for
  65 * workqueue locking issues. It's not meant for executing random crap
  66 * with interrupts disabled. Abuse is monitored!
  67 */
  68#define TIMER_DEFERRABLE                0x1LU
  69#define TIMER_IRQSAFE                   0x2LU
  70
  71#define TIMER_FLAG_MASK                 0x3LU
  72
  73#define __TIMER_INITIALIZER(_function, _expires, _data, _flags) { \
  74                .entry = { .prev = TIMER_ENTRY_STATIC },        \
  75                .function = (_function),                        \
  76                .expires = (_expires),                          \
  77                .data = (_data),                                \
  78                .base = (void *)((unsigned long)&boot_tvec_bases + (_flags)), \
  79                .slack = -1,                                    \
  80                __TIMER_LOCKDEP_MAP_INITIALIZER(                \
  81                        __FILE__ ":" __stringify(__LINE__))     \
  82        }
  83
  84#define TIMER_INITIALIZER(_function, _expires, _data)           \
  85        __TIMER_INITIALIZER((_function), (_expires), (_data), 0)
  86
  87#define TIMER_DEFERRED_INITIALIZER(_function, _expires, _data)  \
  88        __TIMER_INITIALIZER((_function), (_expires), (_data), TIMER_DEFERRABLE)
  89
  90#define DEFINE_TIMER(_name, _function, _expires, _data)         \
  91        struct timer_list _name =                               \
  92                TIMER_INITIALIZER(_function, _expires, _data)
  93
  94void init_timer_key(struct timer_list *timer, unsigned int flags,
  95                    const char *name, struct lock_class_key *key);
  96
  97#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
  98extern void init_timer_on_stack_key(struct timer_list *timer,
  99                                    unsigned int flags, const char *name,
 100                                    struct lock_class_key *key);
 101extern void destroy_timer_on_stack(struct timer_list *timer);
 102#else
 103static inline void destroy_timer_on_stack(struct timer_list *timer) { }
 104static inline void init_timer_on_stack_key(struct timer_list *timer,
 105                                           unsigned int flags, const char *name,
 106                                           struct lock_class_key *key)
 107{
 108        init_timer_key(timer, flags, name, key);
 109}
 110#endif
 111
 112#ifdef CONFIG_LOCKDEP
 113#define __init_timer(_timer, _flags)                                    \
 114        do {                                                            \
 115                static struct lock_class_key __key;                     \
 116                init_timer_key((_timer), (_flags), #_timer, &__key);    \
 117        } while (0)
 118
 119#define __init_timer_on_stack(_timer, _flags)                           \
 120        do {                                                            \
 121                static struct lock_class_key __key;                     \
 122                init_timer_on_stack_key((_timer), (_flags), #_timer, &__key); \
 123        } while (0)
 124#else
 125#define __init_timer(_timer, _flags)                                    \
 126        init_timer_key((_timer), (_flags), NULL, NULL)
 127#define __init_timer_on_stack(_timer, _flags)                           \
 128        init_timer_on_stack_key((_timer), (_flags), NULL, NULL)
 129#endif
 130
 131#define init_timer(timer)                                               \
 132        __init_timer((timer), 0)
 133#define init_timer_deferrable(timer)                                    \
 134        __init_timer((timer), TIMER_DEFERRABLE)
 135#define init_timer_on_stack(timer)                                      \
 136        __init_timer_on_stack((timer), 0)
 137
 138#define __setup_timer(_timer, _fn, _data, _flags)                       \
 139        do {                                                            \
 140                __init_timer((_timer), (_flags));                       \
 141                (_timer)->function = (_fn);                             \
 142                (_timer)->data = (_data);                               \
 143        } while (0)
 144
 145#define __setup_timer_on_stack(_timer, _fn, _data, _flags)              \
 146        do {                                                            \
 147                __init_timer_on_stack((_timer), (_flags));              \
 148                (_timer)->function = (_fn);                             \
 149                (_timer)->data = (_data);                               \
 150        } while (0)
 151
 152#define setup_timer(timer, fn, data)                                    \
 153        __setup_timer((timer), (fn), (data), 0)
 154#define setup_timer_on_stack(timer, fn, data)                           \
 155        __setup_timer_on_stack((timer), (fn), (data), 0)
 156#define setup_deferrable_timer_on_stack(timer, fn, data)                \
 157        __setup_timer_on_stack((timer), (fn), (data), TIMER_DEFERRABLE)
 158
 159/**
 160 * timer_pending - is a timer pending?
 161 * @timer: the timer in question
 162 *
 163 * timer_pending will tell whether a given timer is currently pending,
 164 * or not. Callers must ensure serialization wrt. other operations done
 165 * to this timer, eg. interrupt contexts, or other CPUs on SMP.
 166 *
 167 * return value: 1 if the timer is pending, 0 if not.
 168 */
 169static inline int timer_pending(const struct timer_list * timer)
 170{
 171        return timer->entry.next != NULL;
 172}
 173
 174extern void add_timer_on(struct timer_list *timer, int cpu);
 175extern int del_timer(struct timer_list * timer);
 176extern int mod_timer(struct timer_list *timer, unsigned long expires);
 177extern int mod_timer_pending(struct timer_list *timer, unsigned long expires);
 178extern int mod_timer_pinned(struct timer_list *timer, unsigned long expires);
 179
 180extern void set_timer_slack(struct timer_list *time, int slack_hz);
 181
 182#define TIMER_NOT_PINNED        0
 183#define TIMER_PINNED            1
 184/*
 185 * The jiffies value which is added to now, when there is no timer
 186 * in the timer wheel:
 187 */
 188#define NEXT_TIMER_MAX_DELTA    ((1UL << 30) - 1)
 189
 190/*
 191 * Return when the next timer-wheel timeout occurs (in absolute jiffies),
 192 * locks the timer base and does the comparison against the given
 193 * jiffie.
 194 */
 195extern unsigned long get_next_timer_interrupt(unsigned long now);
 196
 197/*
 198 * Timer-statistics info:
 199 */
 200#ifdef CONFIG_TIMER_STATS
 201
 202extern int timer_stats_active;
 203
 204#define TIMER_STATS_FLAG_DEFERRABLE     0x1
 205
 206extern void init_timer_stats(void);
 207
 208extern void timer_stats_update_stats(void *timer, pid_t pid, void *startf,
 209                                     void *timerf, char *comm,
 210                                     unsigned int timer_flag);
 211
 212extern void __timer_stats_timer_set_start_info(struct timer_list *timer,
 213                                               void *addr);
 214
 215static inline void timer_stats_timer_set_start_info(struct timer_list *timer)
 216{
 217        if (likely(!timer_stats_active))
 218                return;
 219        __timer_stats_timer_set_start_info(timer, __builtin_return_address(0));
 220}
 221
 222static inline void timer_stats_timer_clear_start_info(struct timer_list *timer)
 223{
 224        timer->start_site = NULL;
 225}
 226#else
 227static inline void init_timer_stats(void)
 228{
 229}
 230
 231static inline void timer_stats_timer_set_start_info(struct timer_list *timer)
 232{
 233}
 234
 235static inline void timer_stats_timer_clear_start_info(struct timer_list *timer)
 236{
 237}
 238#endif
 239
 240extern void add_timer(struct timer_list *timer);
 241
 242extern int try_to_del_timer_sync(struct timer_list *timer);
 243
 244#ifdef CONFIG_SMP
 245  extern int del_timer_sync(struct timer_list *timer);
 246#else
 247# define del_timer_sync(t)              del_timer(t)
 248#endif
 249
 250#define del_singleshot_timer_sync(t) del_timer_sync(t)
 251
 252extern void init_timers(void);
 253extern void run_local_timers(void);
 254struct hrtimer;
 255extern enum hrtimer_restart it_real_fn(struct hrtimer *);
 256
 257unsigned long __round_jiffies(unsigned long j, int cpu);
 258unsigned long __round_jiffies_relative(unsigned long j, int cpu);
 259unsigned long round_jiffies(unsigned long j);
 260unsigned long round_jiffies_relative(unsigned long j);
 261
 262unsigned long __round_jiffies_up(unsigned long j, int cpu);
 263unsigned long __round_jiffies_up_relative(unsigned long j, int cpu);
 264unsigned long round_jiffies_up(unsigned long j);
 265unsigned long round_jiffies_up_relative(unsigned long j);
 266
 267#endif
 268
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