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 hlist_node       entry;
  18        unsigned long           expires;
  19        void                    (*function)(unsigned long);
  20        unsigned long           data;
  21        u32                     flags;
  22        int                     slack;
  23
  24#ifdef CONFIG_TIMER_STATS
  25        int                     start_pid;
  26        void                    *start_site;
  27        char                    start_comm[16];
  28#endif
  29#ifdef CONFIG_LOCKDEP
  30        struct lockdep_map      lockdep_map;
  31#endif
  32};
  33
  34#ifdef CONFIG_LOCKDEP
  35/*
  36 * NB: because we have to copy the lockdep_map, setting the lockdep_map key
  37 * (second argument) here is required, otherwise it could be initialised to
  38 * the copy of the lockdep_map later! We use the pointer to and the string
  39 * "<file>:<line>" as the key resp. the name of the lockdep_map.
  40 */
  41#define __TIMER_LOCKDEP_MAP_INITIALIZER(_kn)                            \
  42        .lockdep_map = STATIC_LOCKDEP_MAP_INIT(_kn, &_kn),
  43#else
  44#define __TIMER_LOCKDEP_MAP_INITIALIZER(_kn)
  45#endif
  46
  47/*
  48 * A deferrable timer will work normally when the system is busy, but
  49 * will not cause a CPU to come out of idle just to service it; instead,
  50 * the timer will be serviced when the CPU eventually wakes up with a
  51 * subsequent non-deferrable timer.
  52 *
  53 * An irqsafe timer is executed with IRQ disabled and it's safe to wait for
  54 * the completion of the running instance from IRQ handlers, for example,
  55 * by calling del_timer_sync().
  56 *
  57 * Note: The irq disabled callback execution is a special case for
  58 * workqueue locking issues. It's not meant for executing random crap
  59 * with interrupts disabled. Abuse is monitored!
  60 */
  61#define TIMER_CPUMASK           0x0007FFFF
  62#define TIMER_MIGRATING         0x00080000
  63#define TIMER_BASEMASK          (TIMER_CPUMASK | TIMER_MIGRATING)
  64#define TIMER_DEFERRABLE        0x00100000
  65#define TIMER_IRQSAFE           0x00200000
  66
  67#define __TIMER_INITIALIZER(_function, _expires, _data, _flags) { \
  68                .entry = { .next = TIMER_ENTRY_STATIC },        \
  69                .function = (_function),                        \
  70                .expires = (_expires),                          \
  71                .data = (_data),                                \
  72                .flags = (_flags),                              \
  73                .slack = -1,                                    \
  74                __TIMER_LOCKDEP_MAP_INITIALIZER(                \
  75                        __FILE__ ":" __stringify(__LINE__))     \
  76        }
  77
  78#define TIMER_INITIALIZER(_function, _expires, _data)           \
  79        __TIMER_INITIALIZER((_function), (_expires), (_data), 0)
  80
  81#define TIMER_DEFERRED_INITIALIZER(_function, _expires, _data)  \
  82        __TIMER_INITIALIZER((_function), (_expires), (_data), TIMER_DEFERRABLE)
  83
  84#define DEFINE_TIMER(_name, _function, _expires, _data)         \
  85        struct timer_list _name =                               \
  86                TIMER_INITIALIZER(_function, _expires, _data)
  87
  88void init_timer_key(struct timer_list *timer, unsigned int flags,
  89                    const char *name, struct lock_class_key *key);
  90
  91#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
  92extern void init_timer_on_stack_key(struct timer_list *timer,
  93                                    unsigned int flags, const char *name,
  94                                    struct lock_class_key *key);
  95extern void destroy_timer_on_stack(struct timer_list *timer);
  96#else
  97static inline void destroy_timer_on_stack(struct timer_list *timer) { }
  98static inline void init_timer_on_stack_key(struct timer_list *timer,
  99                                           unsigned int flags, const char *name,
 100                                           struct lock_class_key *key)
 101{
 102        init_timer_key(timer, flags, name, key);
 103}
 104#endif
 105
 106#ifdef CONFIG_LOCKDEP
 107#define __init_timer(_timer, _flags)                                    \
 108        do {                                                            \
 109                static struct lock_class_key __key;                     \
 110                init_timer_key((_timer), (_flags), #_timer, &__key);    \
 111        } while (0)
 112
 113#define __init_timer_on_stack(_timer, _flags)                           \
 114        do {                                                            \
 115                static struct lock_class_key __key;                     \
 116                init_timer_on_stack_key((_timer), (_flags), #_timer, &__key); \
 117        } while (0)
 118#else
 119#define __init_timer(_timer, _flags)                                    \
 120        init_timer_key((_timer), (_flags), NULL, NULL)
 121#define __init_timer_on_stack(_timer, _flags)                           \
 122        init_timer_on_stack_key((_timer), (_flags), NULL, NULL)
 123#endif
 124
 125#define init_timer(timer)                                               \
 126        __init_timer((timer), 0)
 127#define init_timer_deferrable(timer)                                    \
 128        __init_timer((timer), TIMER_DEFERRABLE)
 129#define init_timer_on_stack(timer)                                      \
 130        __init_timer_on_stack((timer), 0)
 131
 132#define __setup_timer(_timer, _fn, _data, _flags)                       \
 133        do {                                                            \
 134                __init_timer((_timer), (_flags));                       \
 135                (_timer)->function = (_fn);                             \
 136                (_timer)->data = (_data);                               \
 137        } while (0)
 138
 139#define __setup_timer_on_stack(_timer, _fn, _data, _flags)              \
 140        do {                                                            \
 141                __init_timer_on_stack((_timer), (_flags));              \
 142                (_timer)->function = (_fn);                             \
 143                (_timer)->data = (_data);                               \
 144        } while (0)
 145
 146#define setup_timer(timer, fn, data)                                    \
 147        __setup_timer((timer), (fn), (data), 0)
 148#define setup_timer_on_stack(timer, fn, data)                           \
 149        __setup_timer_on_stack((timer), (fn), (data), 0)
 150#define setup_deferrable_timer_on_stack(timer, fn, data)                \
 151        __setup_timer_on_stack((timer), (fn), (data), TIMER_DEFERRABLE)
 152
 153/**
 154 * timer_pending - is a timer pending?
 155 * @timer: the timer in question
 156 *
 157 * timer_pending will tell whether a given timer is currently pending,
 158 * or not. Callers must ensure serialization wrt. other operations done
 159 * to this timer, eg. interrupt contexts, or other CPUs on SMP.
 160 *
 161 * return value: 1 if the timer is pending, 0 if not.
 162 */
 163static inline int timer_pending(const struct timer_list * timer)
 164{
 165        return timer->entry.pprev != NULL;
 166}
 167
 168extern void add_timer_on(struct timer_list *timer, int cpu);
 169extern int del_timer(struct timer_list * timer);
 170extern int mod_timer(struct timer_list *timer, unsigned long expires);
 171extern int mod_timer_pending(struct timer_list *timer, unsigned long expires);
 172extern int mod_timer_pinned(struct timer_list *timer, unsigned long expires);
 173
 174extern void set_timer_slack(struct timer_list *time, int slack_hz);
 175
 176#define TIMER_NOT_PINNED        0
 177#define TIMER_PINNED            1
 178/*
 179 * The jiffies value which is added to now, when there is no timer
 180 * in the timer wheel:
 181 */
 182#define NEXT_TIMER_MAX_DELTA    ((1UL << 30) - 1)
 183
 184/*
 185 * Timer-statistics info:
 186 */
 187#ifdef CONFIG_TIMER_STATS
 188
 189extern int timer_stats_active;
 190
 191extern void init_timer_stats(void);
 192
 193extern void timer_stats_update_stats(void *timer, pid_t pid, void *startf,
 194                                     void *timerf, char *comm, u32 flags);
 195
 196extern void __timer_stats_timer_set_start_info(struct timer_list *timer,
 197                                               void *addr);
 198
 199static inline void timer_stats_timer_set_start_info(struct timer_list *timer)
 200{
 201        if (likely(!timer_stats_active))
 202                return;
 203        __timer_stats_timer_set_start_info(timer, __builtin_return_address(0));
 204}
 205
 206static inline void timer_stats_timer_clear_start_info(struct timer_list *timer)
 207{
 208        timer->start_site = NULL;
 209}
 210#else
 211static inline void init_timer_stats(void)
 212{
 213}
 214
 215static inline void timer_stats_timer_set_start_info(struct timer_list *timer)
 216{
 217}
 218
 219static inline void timer_stats_timer_clear_start_info(struct timer_list *timer)
 220{
 221}
 222#endif
 223
 224extern void add_timer(struct timer_list *timer);
 225
 226extern int try_to_del_timer_sync(struct timer_list *timer);
 227
 228#ifdef CONFIG_SMP
 229  extern int del_timer_sync(struct timer_list *timer);
 230#else
 231# define del_timer_sync(t)              del_timer(t)
 232#endif
 233
 234#define del_singleshot_timer_sync(t) del_timer_sync(t)
 235
 236extern void init_timers(void);
 237extern void run_local_timers(void);
 238struct hrtimer;
 239extern enum hrtimer_restart it_real_fn(struct hrtimer *);
 240
 241#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
 242#include <linux/sysctl.h>
 243
 244extern unsigned int sysctl_timer_migration;
 245int timer_migration_handler(struct ctl_table *table, int write,
 246                            void __user *buffer, size_t *lenp,
 247                            loff_t *ppos);
 248#endif
 249
 250unsigned long __round_jiffies(unsigned long j, int cpu);
 251unsigned long __round_jiffies_relative(unsigned long j, int cpu);
 252unsigned long round_jiffies(unsigned long j);
 253unsigned long round_jiffies_relative(unsigned long j);
 254
 255unsigned long __round_jiffies_up(unsigned long j, int cpu);
 256unsigned long __round_jiffies_up_relative(unsigned long j, int cpu);
 257unsigned long round_jiffies_up(unsigned long j);
 258unsigned long round_jiffies_up_relative(unsigned long j);
 259
 260#endif
 261