linux/kernel/time
Thomas Gleixner 1bd04bf6f6 timer: Remove FIFO "guarantee"
The FIFO guarantee is only there if two timers are queued into the
same bucket at the same jiffie on the same cpu:

 - The slack value depends on the delta between expiry and enqueue
   time, so the resulting expiry time can be different for timers
   which are queued in different jiffies.

 - Timers which are queued into the secondary array end up after a
   later queued timer which was queued into the primary array due to
   cascading.

 - Timers can end up on different cpus due to the NOHZ target moving
   around. Obviously there is no guarantee of expiry ordering between
   cpus.

So anything which relies on FIFO behaviour of the timer wheel is
broken already.

This is a preparatory patch for converting the timer wheel to hlist
which reduces the memory foot print of the wheel by 50%.

It's a seperate patch so any (unlikely to happen) regression caused by
this can be identified clearly.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Joonwoo Park <joonwoop@codeaurora.org>
Cc: Wenbo Wang <wenbo.wang@memblaze.com>
Cc: George Spelvin <linux@horizon.com>
Link: http://lkml.kernel.org/r/20150526224511.757520403@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-06-19 15:18:27 +02:00
..
alarmtimer.c alarmtimer: Get rid of unused return value 2015-04-22 17:06:52 +02:00
clockevents.c clockevents: Check state instead of mode in suspend/resume path 2015-06-18 09:27:02 +02:00
clocksource.c clocksource: Use current logging style 2015-06-10 11:31:14 +02:00
hrtimer.c hrtimer: Allow hrtimer::function() to free the timer 2015-06-19 00:09:56 +02:00
itimer.c time/timers: Move all time(r) related files into kernel/time 2014-06-23 11:22:35 +02:00
jiffies.c tick: Move clocksource related stuff to timekeeping.h 2015-04-01 14:22:58 +02:00
Kconfig clockevents: Remove CONFIG_GENERIC_CLOCKEVENTS_BUILD 2015-04-01 14:22:57 +02:00
Makefile time: Move timeconst.h into include/generated 2015-05-19 15:13:45 +02:00
ntp_internal.h time: Prevent early expiry of hrtimers[CLOCK_REALTIME] at the leap second edge 2015-06-12 11:15:49 +02:00
ntp.c ntp: Do leapsecond adjustment in adjtimex read path 2015-06-12 11:15:49 +02:00
posix-clock.c kernel: Fix files explicitly needing EXPORT_SYMBOL infrastructure 2011-10-31 19:30:05 -04:00
posix-cpu-timers.c all arches, signal: move restart_block to struct task_struct 2015-02-12 18:54:12 -08:00
posix-timers.c hrtimer: Get rid of hrtimer_get_res() 2015-04-22 17:06:49 +02:00
sched_clock.c timers, sched/clock: Clean up the code a bit 2015-03-27 08:34:01 +01:00
test_udelay.c time: Rename udelay_test.c to test_udelay.c 2014-11-21 11:59:55 -08:00
tick-broadcast-hrtimer.c tick: hrtimer-broadcast: Prevent endless restarting when broadcast device is unused 2015-05-05 15:34:21 +02:00
tick-broadcast.c clockevents: Provide functions to set and get the state 2015-06-02 14:40:47 +02:00
tick-common.c clockevents: Use set/get state helper functions 2015-06-02 14:40:48 +02:00
tick-internal.h clockevents: Rename state to state_use_accessors 2015-06-02 16:56:42 +02:00
tick-oneshot.c clockevents: Provide functions to set and get the state 2015-06-02 14:40:47 +02:00
tick-sched.c nohz: Fix !HIGH_RES_TIMERS hang 2015-05-07 16:15:50 +02:00
tick-sched.h tick: Nohz: Rework next timer evaluation 2015-04-22 17:06:50 +02:00
time.c time: Refactor usecs_to_jiffies 2015-06-10 11:31:13 +02:00
timeconst.bc time: Move timeconst.h into include/generated 2015-05-19 15:13:45 +02:00
timeconv.c
timecounter.c timecounter: keep track of accumulated fractional nanoseconds 2014-12-30 18:29:27 -05:00
timekeeping_debug.c timekeeping: Convert timekeeping core to use timespec64s 2014-07-23 10:17:54 -07:00
timekeeping_internal.h clocksource: Move cycle_last validation to core code 2014-07-23 15:01:51 -07:00
timekeeping.c timekeeping: Copy the shadow-timekeeper over the real timekeeper last 2015-06-18 09:27:02 +02:00
timekeeping.h hrtimer: Make offset update smarter 2015-04-22 17:06:49 +02:00
timer_list.c clockevents: Introduce CLOCK_EVT_STATE_ONESHOT_STOPPED state 2015-05-19 16:18:02 +02:00
timer_stats.c timer stats: Add a 'Collection: active/inactive' line to timer usage statistics 2013-10-10 09:59:25 +02:00
timer.c timer: Remove FIFO "guarantee" 2015-06-19 15:18:27 +02:00