3  * 2002-10-15  Posix Clocks & timers
10  * These are all the functions necessary to implement POSIX clocks & timers
25 #include <linux/posix-timers.h>
36 #include "posix-timers.h"
41  * Timers are managed in a hash table for lockless lookup. The hash key is
279  * whether the signal should be dropped and rearms interval timers.  The
316  * based timers.
522 	 * The hash lookup and the timers are RCU protected.  in __lock_timer()
524 	 * Timers are added to the hash in invalid state where  in __lock_timer()
590  *  2) The timer is a SIGEV_NONE timer. These timers are never enqueued
608 		 * SIGEV_NONE oneshot timers are never queued and therefore  in common_timer_get()
612 		 * For all other timers there is nothing to update here, so  in common_timer_get()
635 	 * Consequently all interval timers, i.e. @iv > 0, cannot have a  in common_timer_get()
642 		 * expired! Timers which have a real signal delivery mode  in common_timer_get()
748 	 * Posix magic: Relative CLOCK_REALTIME timers are not affected by  in common_hrtimer_arm()
788  * For POSIX CPU timers with CONFIG_POSIX_CPU_TIMERS_TASK_WORK=n this is
1086  * At that point no other task can access the timers of the dying
1091 	struct hlist_head timers;  in exit_itimers()  local
1096 	/* Protect against concurrent read via /proc/$PID/timers */  in exit_itimers()
1098 	hlist_move_list(&tsk->signal->posix_timers, &timers);  in exit_itimers()
1101 	/* The timers are not longer accessible via tsk::signal */  in exit_itimers()
1102 	while (!hlist_empty(&timers))  in exit_itimers()
1103 		itimer_delete(hlist_entry(timers.first, struct k_itimer, list));  in exit_itimers()
1106 	 * There should be no timers on the ignored list. itimer_delete() has  in exit_itimers()
1112 	hlist_move_list(&tsk->signal->ignored_posix_timers, &timers);  in exit_itimers()
1113 	while (!hlist_empty(&timers)) {  in exit_itimers()
1114 		posix_timer_cleanup_ignored(hlist_entry(timers.first, struct k_itimer,  in exit_itimers()
1203  * resolutions for reading the time and for arming timers.
1215  *	  When high resolution timers are disabled at compile or runtime
1217  *	  the precision at which timers expire.
1221  *	  When high resolution timers are enabled the resolution returned