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_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  */
 163 static inline int timer_pending(const struct timer_list * timer)
 164 {
 165         return timer->entry.pprev != NULL;
 166 }
 167
 168 extern void add_timer_on(struct timer_list *timer, int cpu);
 169 extern int del_timer(struct timer_list * timer);
 170 extern int mod_timer(struct timer_list *timer, unsigned long expires);
 171 extern int mod_timer_pending(struct timer_list *timer, unsigned long expires);
 172 extern int mod_timer_pinned(struct timer_list *timer, unsigned long expires);
 173
 174 extern 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
 189 extern int timer_stats_active;
 190
 191 extern void init_timer_stats(void);
 192
 193 extern void timer_stats_update_stats(void *timer, pid_t pid, void *startf,
 194                                      void *timerf, char *comm, u32 flags);
 195
 196 extern void __timer_stats_timer_set_start_info(struct timer_list *timer,
 197                                                void *addr);
 198
 199 static 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
 206 static inline void timer_stats_timer_clear_start_info(struct timer_list *timer)
 207 {
 208         timer->start_site = NULL;
 209 }
 210 #else
 211 static inline void init_timer_stats(void)
 212 {
 213 }
 214
 215 static inline void timer_stats_timer_set_start_info(struct timer_list *timer)
 216 {
 217 }
 218
 219 static inline void timer_stats_timer_clear_start_info(struct timer_list *timer)
 220 {
 221 }
 222 #endif
 223
 224 extern void add_timer(struct timer_list *timer);
 225
 226 extern 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
 236 extern void init_timers(void);
 237 extern void run_local_timers(void);
 238 struct hrtimer;
 239 extern 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
 244 extern unsigned int sysctl_timer_migration;
 245 int timer_migration_handler(struct ctl_table *table, int write,
 246                             void __user *buffer, size_t *lenp,
 247                             loff_t *ppos);
 248 #endif
 249
 250 unsigned long __round_jiffies(unsigned long j, int cpu);
 251 unsigned long __round_jiffies_relative(unsigned long j, int cpu);
 252 unsigned long round_jiffies(unsigned long j);
 253 unsigned long round_jiffies_relative(unsigned long j);
 254
 255 unsigned long __round_jiffies_up(unsigned long j, int cpu);
 256 unsigned long __round_jiffies_up_relative(unsigned long j, int cpu);
 257 unsigned long round_jiffies_up(unsigned long j);
 258 unsigned long round_jiffies_up_relative(unsigned long j);
 259
 260 #endif