include/linux/timer.h

   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
  10 struct tvec_base;
  11
  12 struct 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_LOCKDEP
  25         struct lockdep_map      lockdep_map;
  26 #endif
  27 };
  28
  29 #ifdef CONFIG_LOCKDEP
  30 /*
  31  * NB: because we have to copy the lockdep_map, setting the lockdep_map key
  32  * (second argument) here is required, otherwise it could be initialised to
  33  * the copy of the lockdep_map later! We use the pointer to and the string
  34  * "<file>:<line>" as the key resp. the name of the lockdep_map.
  35  */
  36 #define __TIMER_LOCKDEP_MAP_INITIALIZER(_kn)                            \
  37         .lockdep_map = STATIC_LOCKDEP_MAP_INIT(_kn, &_kn),
  38 #else
  39 #define __TIMER_LOCKDEP_MAP_INITIALIZER(_kn)
  40 #endif
  41
  42 /*
  43  * A deferrable timer will work normally when the system is busy, but
  44  * will not cause a CPU to come out of idle just to service it; instead,
  45  * the timer will be serviced when the CPU eventually wakes up with a
  46  * subsequent non-deferrable timer.
  47  *
  48  * An irqsafe timer is executed with IRQ disabled and it's safe to wait for
  49  * the completion of the running instance from IRQ handlers, for example,
  50  * by calling del_timer_sync().
  51  *
  52  * Note: The irq disabled callback execution is a special case for
  53  * workqueue locking issues. It's not meant for executing random crap
  54  * with interrupts disabled. Abuse is monitored!
  55  */
  56 #define TIMER_CPUMASK           0x0007FFFF
  57 #define TIMER_MIGRATING         0x00080000
  58 #define TIMER_BASEMASK          (TIMER_CPUMASK | TIMER_MIGRATING)
  59 #define TIMER_DEFERRABLE        0x00100000
  60 #define TIMER_IRQSAFE           0x00200000
  61 #define TIMER_PINNED_ON_CPU     0x00400000
  62
  63 #define __TIMER_INITIALIZER(_function, _expires, _data, _flags) { \
  64                 .entry = { .next = TIMER_ENTRY_STATIC },        \
  65                 .function = (_function),                        \
  66                 .expires = (_expires),                          \
  67                 .data = (_data),                                \
  68                 .flags = (_flags),                              \
  69                 .slack = -1,                                    \
  70                 __TIMER_LOCKDEP_MAP_INITIALIZER(                \
  71                         __FILE__ ":" __stringify(__LINE__))     \
  72         }
  73
  74 #define TIMER_INITIALIZER(_function, _expires, _data)           \
  75         __TIMER_INITIALIZER((_function), (_expires), (_data), 0)
  76
  77 #define TIMER_DEFERRED_INITIALIZER(_function, _expires, _data)  \
  78         __TIMER_INITIALIZER((_function), (_expires), (_data), TIMER_DEFERRABLE)
  79
  80 #define DEFINE_TIMER(_name, _function, _expires, _data)         \
  81         struct timer_list _name =                               \
  82                 TIMER_INITIALIZER(_function, _expires, _data)
  83
  84 void init_timer_key(struct timer_list *timer, unsigned int flags,
  85                     const char *name, struct lock_class_key *key);
  86
  87 #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
  88 extern void init_timer_on_stack_key(struct timer_list *timer,
  89                                     unsigned int flags, const char *name,
  90                                     struct lock_class_key *key);
  91 extern void destroy_timer_on_stack(struct timer_list *timer);
  92 #else
  93 static inline void destroy_timer_on_stack(struct timer_list *timer) { }
  94 static inline void init_timer_on_stack_key(struct timer_list *timer,
  95                                            unsigned int flags, const char *name,
  96                                            struct lock_class_key *key)
  97 {
  98         init_timer_key(timer, flags, name, key);
  99 }
 100 #endif
 101
 102 #ifdef CONFIG_LOCKDEP
 103 #define __init_timer(_timer, _flags)                                    \
 104         do {                                                            \
 105                 static struct lock_class_key __key;                     \
 106                 init_timer_key((_timer), (_flags), #_timer, &__key);    \
 107         } while (0)
 108
 109 #define __init_timer_on_stack(_timer, _flags)                           \
 110         do {                                                            \
 111                 static struct lock_class_key __key;                     \
 112                 init_timer_on_stack_key((_timer), (_flags), #_timer, &__key); \
 113         } while (0)
 114 #else
 115 #define __init_timer(_timer, _flags)                                    \
 116         init_timer_key((_timer), (_flags), NULL, NULL)
 117 #define __init_timer_on_stack(_timer, _flags)                           \
 118         init_timer_on_stack_key((_timer), (_flags), NULL, NULL)
 119 #endif
 120
 121 #define init_timer(timer)                                               \
 122         __init_timer((timer), 0)
 123 #define init_timer_deferrable(timer)                                    \
 124         __init_timer((timer), TIMER_DEFERRABLE)
 125 #define init_timer_on_stack(timer)                                      \
 126         __init_timer_on_stack((timer), 0)
 127
 128 #define __setup_timer(_timer, _fn, _data, _flags)                       \
 129         do {                                                            \
 130                 __init_timer((_timer), (_flags));                       \
 131                 (_timer)->function = (_fn);                             \
 132                 (_timer)->data = (_data);                               \
 133         } while (0)
 134
 135 #define __setup_timer_on_stack(_timer, _fn, _data, _flags)              \
 136         do {                                                            \
 137                 __init_timer_on_stack((_timer), (_flags));              \
 138                 (_timer)->function = (_fn);                             \
 139                 (_timer)->data = (_data);                               \
 140         } while (0)
 141
 142 #define setup_timer(timer, fn, data)                                    \
 143         __setup_timer((timer), (fn), (data), 0)
 144 #define setup_timer_on_stack(timer, fn, data)                           \
 145         __setup_timer_on_stack((timer), (fn), (data), 0)
 146 #define setup_deferrable_timer_on_stack(timer, fn, data)                \
 147         __setup_timer_on_stack((timer), (fn), (data), TIMER_DEFERRABLE)
 148
 149 /**
 150  * timer_pending - is a timer pending?
 151  * @timer: the timer in question
 152  *
 153  * timer_pending will tell whether a given timer is currently pending,
 154  * or not. Callers must ensure serialization wrt. other operations done
 155  * to this timer, eg. interrupt contexts, or other CPUs on SMP.
 156  *
 157  * return value: 1 if the timer is pending, 0 if not.
 158  */
 159 static inline int timer_pending(const struct timer_list * timer)
 160 {
 161         return timer->entry.pprev != NULL;
 162 }
 163
 164 extern void add_timer_on(struct timer_list *timer, int cpu);
 165 extern int del_timer(struct timer_list * timer);
 166 extern int mod_timer(struct timer_list *timer, unsigned long expires);
 167 extern int mod_timer_pending(struct timer_list *timer, unsigned long expires);
 168 extern int mod_timer_pinned(struct timer_list *timer, unsigned long expires);
 169
 170 extern void set_timer_slack(struct timer_list *time, int slack_hz);
 171 #ifdef CONFIG_SMP
 172 extern bool check_pending_deferrable_timers(int cpu);
 173 #endif
 174
 175 #define TIMER_NOT_PINNED        0
 176 #define TIMER_PINNED            1
 177 /*
 178  * The jiffies value which is added to now, when there is no timer
 179  * in the timer wheel:
 180  */
 181 #define NEXT_TIMER_MAX_DELTA    ((1UL << 30) - 1)
 182
 183 /* To be used from cpusets, only */
 184 extern void timer_quiesce_cpu(void *cpup);
 185
 186 extern void add_timer(struct timer_list *timer);
 187
 188 extern int try_to_del_timer_sync(struct timer_list *timer);
 189
 190 #ifdef CONFIG_SMP
 191   extern int del_timer_sync(struct timer_list *timer);
 192 #else
 193 # define del_timer_sync(t)              del_timer(t)
 194 #endif
 195
 196 #define del_singleshot_timer_sync(t) del_timer_sync(t)
 197
 198 extern void init_timers(void);
 199 extern void run_local_timers(void);
 200 struct hrtimer;
 201 extern enum hrtimer_restart it_real_fn(struct hrtimer *);
 202
 203 #if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
 204 #include <linux/sysctl.h>
 205
 206 extern struct tvec_base tvec_base_deferrable;
 207
 208 extern unsigned int sysctl_timer_migration;
 209 int timer_migration_handler(struct ctl_table *table, int write,
 210                             void __user *buffer, size_t *lenp,
 211                             loff_t *ppos);
 212 #endif
 213
 214 unsigned long __round_jiffies(unsigned long j, int cpu);
 215 unsigned long __round_jiffies_relative(unsigned long j, int cpu);
 216 unsigned long round_jiffies(unsigned long j);
 217 unsigned long round_jiffies_relative(unsigned long j);
 218
 219 unsigned long __round_jiffies_up(unsigned long j, int cpu);
 220 unsigned long __round_jiffies_up_relative(unsigned long j, int cpu);
 221 unsigned long round_jiffies_up(unsigned long j);
 222 unsigned long round_jiffies_up_relative(unsigned long j);
 223
 224 #endif