kernel/time/timer.c

3  *  Kernel internal timers
7  *  1997-01-28  Modified by Finn Arne Gangstad to make timers scale better.
33 #include <linux/posix-timers.h>
78  * expiry of the timers, this implementation removes the need for recascading
79  * the timers into the lower array levels. The previous 'classic' timer wheel
86  * timeout timers (networking, disk I/O ...) are canceled before expiry. If
90  * The only exception to this are networking timers with a small expiry
94  * We don't have cascading anymore. timers with a expiry time above the
186  * wheels so we have a separate storage for the deferrable timers.
209  * @running_timer:	When expiring timers, the lock is dropped. To make
239  *			base. Deferrable timers, which are enqueued remotely
248  *			of the timer wheel. The list contains all timers
356 	 * We don't want all cpus firing their timers at once hitting the
395  * up or down to (approximately) full seconds. This is useful for timers
399  * By rounding these timers to whole seconds, all such timers will fire
421  * up or down to (approximately) full seconds. This is useful for timers
425  * By rounding these timers to whole seconds, all such timers will fire
449  * up or down to (approximately) full seconds. This is useful for timers
453  * By rounding these timers to whole seconds, all such timers will fire
470  * up or down to (approximately) full seconds. This is useful for timers
474  * By rounding these timers to whole seconds, all such timers will fire
626 	 * Deferrable timers do not prevent the CPU from entering dynticks and
630 	 * the remote IPI for deferrable timers completely.
756 /* Stub timer callback for improperly used timers. */
1025  * that all timers which are tied to this base are locked, and the base itself
1028  * So __run_timers/migrate_timers can safely modify all timers which could
1196  * mod_timer_pending() is the same for pending timers as mod_timer(), but
1197  * will not activate inactive timers.
1687  * For !irqsafe timers, the caller must not hold locks that are held in
1982 	 * If high resolution timers are enabled
1996 	 * Round up to the next jiffie. High resolution timers are
2056 		 * * The remote callers will only take care of the global timers
2057 		 *   as local timers will be handled by CPU itself. When not
2086  * fetch_next_timer_interrupt_remote() - Store next timers into @tevt
2171  * timer_expire_remote() - expire global timers of cpu
2174  * Expire timers of global base of remote CPU.
2198 	 * sure the CPU will wake up in time to handle remote timers.
2290 		 * BASE_GLOBAL base, deferrable timers may still see large
2296 			 * Global timers queued locally while running in a task
2384  * __run_timers - run all expired timers (if any) on this CPU.
2402 		 * timer at this clk are that all matching timers have been
2410 		 * While executing timers, base->clk is set 1 offset ahead of
2441  * This function runs timers and the timer-tq in bottom half context.
2678 		 * before moving the timers over.