linux/kernel/time
Sebastien Dugue 94df7de028 hrtimers: allow the hot-unplugging of all cpus
Impact: fix CPU hotplug hang on Power6 testbox

On architectures that support offlining all cpus (at least powerpc/pseries),
hot-unpluging the tick_do_timer_cpu can result in a system hang.

This comes from the fact that if the cpu going down happens to be the
cpu doing the tick, then as the tick_do_timer_cpu handover happens after the
cpu is dead (via the CPU_DEAD notification), we're left without ticks,
jiffies are frozen and any task relying on timers (msleep, ...) is stuck.
That's particularly the case for the cpu looping in __cpu_die() waiting
for the dying cpu to be dead.

This patch addresses this by having the tick_do_timer_cpu handover happen
earlier during the CPU_DYING notification. For this, a new clockevent
notification type is introduced (CLOCK_EVT_NOTIFY_CPU_DYING) which is triggered
in hrtimer_cpu_notify().

Signed-off-by: Sebastien Dugue <sebastien.dugue@bull.net>
Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-30 22:35:29 +01:00
..
clockevents.c cpumask: convert struct clock_event_device to cpumask pointers. 2008-12-13 21:20:26 +10:30
clocksource.c cpumask: replace for_each_cpu_mask_nr with for_each_cpu in kernel/time/ 2009-01-01 10:12:29 +10:30
jiffies.c trivial: fix then -> than typos in comments and documentation 2009-01-06 11:28:06 +01:00
Kconfig Kconfig: eliminate "def_bool n" constructs 2008-10-16 11:21:31 -07:00
Makefile clockevents: Allow build w/o run-tine usage for migration purposes 2007-10-12 23:04:05 +02:00
ntp.c hrtimer: removing all ur callback modes 2008-11-25 15:45:46 +01:00
tick-broadcast.c cpumask: replace for_each_cpu_mask_nr with for_each_cpu in kernel/time/ 2009-01-01 10:12:29 +10:30
tick-common.c hrtimers: allow the hot-unplugging of all cpus 2009-01-30 22:35:29 +01:00
tick-internal.h NOHZ: restart tick device from irq_enter() 2008-10-17 18:13:38 +02:00
tick-oneshot.c clockevents: remove WARN_ON which was used to gather information 2008-09-09 22:20:01 +02:00
tick-sched.c time-sched.c: tick_nohz_update_jiffies should be static 2009-01-15 12:06:56 +01:00
timekeeping.c sched_clock: prevent scd->clock from moving backwards, take #2 2008-12-31 09:53:21 +01:00
timer_list.c Merge branch 'timers/range-hrtimers' into v28-range-hrtimers-for-linus-v2 2008-10-22 09:48:06 +02:00
timer_stats.c kernel: use non-racy method for proc entries creation 2008-04-29 08:06:22 -07:00