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 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
  36 extern 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
  94 void 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
  98 extern void init_timer_on_stack_key(struct timer_list *timer,
  99                                     unsigned int flags, const char *name,
 100                                     struct lock_class_key *key);
 101 extern void destroy_timer_on_stack(struct timer_list *timer);
 102 #else
 103 static inline void destroy_timer_on_stack(struct timer_list *timer) { }
 104 static 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  */
 169 static inline int timer_pending(const struct timer_list * timer)
 170 {
 171         return timer->entry.next != NULL;
 172 }
 173
 174 extern void add_timer_on(struct timer_list *timer, int cpu);
 175 extern int del_timer(struct timer_list * timer);
 176 extern int mod_timer(struct timer_list *timer, unsigned long expires);
 177 extern int mod_timer_pending(struct timer_list *timer, unsigned long expires);
 178 extern int mod_timer_pinned(struct timer_list *timer, unsigned long expires);
 179
 180 extern 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  */
 195 extern unsigned long get_next_timer_interrupt(unsigned long now);
 196
 197 /*
 198  * Timer-statistics info:
 199  */
 200 #ifdef CONFIG_TIMER_STATS
 201
 202 extern int timer_stats_active;
 203
 204 #define TIMER_STATS_FLAG_DEFERRABLE     0x1
 205
 206 extern void init_timer_stats(void);
 207
 208 extern void timer_stats_update_stats(void *timer, pid_t pid, void *startf,
 209                                      void *timerf, char *comm,
 210                                      unsigned int timer_flag);
 211
 212 extern void __timer_stats_timer_set_start_info(struct timer_list *timer,
 213                                                void *addr);
 214
 215 static 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
 222 static inline void timer_stats_timer_clear_start_info(struct timer_list *timer)
 223 {
 224         timer->start_site = NULL;
 225 }
 226 #else
 227 static inline void init_timer_stats(void)
 228 {
 229 }
 230
 231 static inline void timer_stats_timer_set_start_info(struct timer_list *timer)
 232 {
 233 }
 234
 235 static inline void timer_stats_timer_clear_start_info(struct timer_list *timer)
 236 {
 237 }
 238 #endif
 239
 240 extern void add_timer(struct timer_list *timer);
 241
 242 extern 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
 252 extern void init_timers(void);
 253 extern void run_local_timers(void);
 254 struct hrtimer;
 255 extern enum hrtimer_restart it_real_fn(struct hrtimer *);
 256
 257 unsigned long __round_jiffies(unsigned long j, int cpu);
 258 unsigned long __round_jiffies_relative(unsigned long j, int cpu);
 259 unsigned long round_jiffies(unsigned long j);
 260 unsigned long round_jiffies_relative(unsigned long j);
 261
 262 unsigned long __round_jiffies_up(unsigned long j, int cpu);
 263 unsigned long __round_jiffies_up_relative(unsigned long j, int cpu);
 264 unsigned long round_jiffies_up(unsigned long j);
 265 unsigned long round_jiffies_up_relative(unsigned long j);
 266
 267 #endif