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| author | Sebastien Dugue <sebastien.dugue@bull.net> | 2008-12-01 14:09:07 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-12-30 07:37:19 +0100 |
| commit | 5762ba1873b0bb9faa631aaa02f533c2b9837f82 (patch) | |
| tree | 3ea61b03a12ec16620f8527c4c83cb90d80cf6cc /include/linux | |
| parent | 0ce74d9296c971b2355c26984ad0bc538e34dd6c (diff) | |
| download | cachepc-linux-5762ba1873b0bb9faa631aaa02f533c2b9837f82.tar.gz cachepc-linux-5762ba1873b0bb9faa631aaa02f533c2b9837f82.zip | |
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>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/clockchips.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/clockchips.h b/include/linux/clockchips.h index ed3a5d473e52..c6de413c5dd1 100644 --- a/include/linux/clockchips.h +++ b/include/linux/clockchips.h @@ -36,6 +36,7 @@ enum clock_event_nofitiers { CLOCK_EVT_NOTIFY_BROADCAST_EXIT, CLOCK_EVT_NOTIFY_SUSPEND, CLOCK_EVT_NOTIFY_RESUME, + CLOCK_EVT_NOTIFY_CPU_DYING, CLOCK_EVT_NOTIFY_CPU_DEAD, }; |