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_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
  88 void 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
  92 extern void init_timer_on_stack_key(struct timer_list *timer,
  93                                     unsigned int flags, const char *name,
  94                                     struct lock_class_key *key);
  95 extern void destroy_timer_on_stack(struct timer_list *timer);
  96 #else
  97 static inline void destroy_timer_on_stack(struct timer_list *timer) { }
  98 static 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_deferrable_timer(timer, fn, data)                         \
 149         __setup_timer((timer), (fn), (data), TIMER_DEFERRABLE)
 150 #define setup_timer_on_stack(timer, fn, data)                           \
 151         __setup_timer_on_stack((timer), (fn), (data), 0)
 152 #define setup_deferrable_timer_on_stack(timer, fn, data)                \
 153         __setup_timer_on_stack((timer), (fn), (data), TIMER_DEFERRABLE)
 154
 155 /**
 156  * timer_pending - is a timer pending?
 157  * @timer: the timer in question
 158  *
 159  * timer_pending will tell whether a given timer is currently pending,
 160  * or not. Callers must ensure serialization wrt. other operations done
 161  * to this timer, eg. interrupt contexts, or other CPUs on SMP.
 162  *
 163  * return value: 1 if the timer is pending, 0 if not.
 164  */
 165 static inline int timer_pending(const struct timer_list * timer)
 166 {
 167         return timer->entry.pprev != NULL;
 168 }
 169
 170 extern void add_timer_on(struct timer_list *timer, int cpu);
 171 extern int del_timer(struct timer_list * timer);
 172 extern int mod_timer(struct timer_list *timer, unsigned long expires);
 173 extern int mod_timer_pending(struct timer_list *timer, unsigned long expires);
 174 extern int mod_timer_pinned(struct timer_list *timer, unsigned long expires);
 175
 176 extern void set_timer_slack(struct timer_list *time, int slack_hz);
 177
 178 #define TIMER_NOT_PINNED        0
 179 #define TIMER_PINNED            1
 180 /*
 181  * The jiffies value which is added to now, when there is no timer
 182  * in the timer wheel:
 183  */
 184 #define NEXT_TIMER_MAX_DELTA    ((1UL << 30) - 1)
 185
 186 /*
 187  * Timer-statistics info:
 188  */
 189 #ifdef CONFIG_TIMER_STATS
 190
 191 extern int timer_stats_active;
 192
 193 extern void init_timer_stats(void);
 194
 195 extern void timer_stats_update_stats(void *timer, pid_t pid, void *startf,
 196                                      void *timerf, char *comm, u32 flags);
 197
 198 extern void __timer_stats_timer_set_start_info(struct timer_list *timer,
 199                                                void *addr);
 200
 201 static inline void timer_stats_timer_set_start_info(struct timer_list *timer)
 202 {
 203         if (likely(!timer_stats_active))
 204                 return;
 205         __timer_stats_timer_set_start_info(timer, __builtin_return_address(0));
 206 }
 207
 208 static inline void timer_stats_timer_clear_start_info(struct timer_list *timer)
 209 {
 210         timer->start_site = NULL;
 211 }
 212 #else
 213 static inline void init_timer_stats(void)
 214 {
 215 }
 216
 217 static inline void timer_stats_timer_set_start_info(struct timer_list *timer)
 218 {
 219 }
 220
 221 static inline void timer_stats_timer_clear_start_info(struct timer_list *timer)
 222 {
 223 }
 224 #endif
 225
 226 extern void add_timer(struct timer_list *timer);
 227
 228 extern int try_to_del_timer_sync(struct timer_list *timer);
 229
 230 #ifdef CONFIG_SMP
 231   extern int del_timer_sync(struct timer_list *timer);
 232 #else
 233 # define del_timer_sync(t)              del_timer(t)
 234 #endif
 235
 236 #define del_singleshot_timer_sync(t) del_timer_sync(t)
 237
 238 extern void init_timers(void);
 239 extern void run_local_timers(void);
 240 struct hrtimer;
 241 extern enum hrtimer_restart it_real_fn(struct hrtimer *);
 242
 243 #if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
 244 #include <linux/sysctl.h>
 245
 246 extern unsigned int sysctl_timer_migration;
 247 int timer_migration_handler(struct ctl_table *table, int write,
 248                             void __user *buffer, size_t *lenp,
 249                             loff_t *ppos);
 250 #endif
 251
 252 unsigned long __round_jiffies(unsigned long j, int cpu);
 253 unsigned long __round_jiffies_relative(unsigned long j, int cpu);
 254 unsigned long round_jiffies(unsigned long j);
 255 unsigned long round_jiffies_relative(unsigned long j);
 256
 257 unsigned long __round_jiffies_up(unsigned long j, int cpu);
 258 unsigned long __round_jiffies_up_relative(unsigned long j, int cpu);
 259 unsigned long round_jiffies_up(unsigned long j);
 260 unsigned long round_jiffies_up_relative(unsigned long j);
 261
 262 #endif