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hrtimer: prevent migration of per CPU hrtimers

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Impact: per CPU hrtimers can be migrated from a dead CPU

The hrtimer code has no knowledge about per CPU timers, but we need to
prevent the migration of such timers and warn when such a timer is
active at migration time.

Explicitely mark the timers as per CPU and use a more understandable
mode descriptor for the interrupts safe unlocked callback mode, which
is used by hrtimer_sleeper and the scheduler code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Thomas Gleixner
2008-09-29 15:47:42 +02:00
parent b00c1a99e7
commit ccc7dadf73
5 changed files with 40 additions and 19 deletions
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14
include/linux/hrtimer.h
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@ -47,14 +47,22 @@ enum hrtimer_restart {
* HRTIMER_CB_IRQSAFE: Callback may run in hardirq context
* HRTIMER_CB_IRQSAFE_NO_RESTART: Callback may run in hardirq context and
* does not restart the timer
* HRTIMER_CB_IRQSAFE_NO_SOFTIRQ: Callback must run in hardirq context
* Special mode for tick emultation
* HRTIMER_CB_IRQSAFE_PERCPU: Callback must run in hardirq context
* Special mode for tick emulation and
* scheduler timer. Such timers are per
* cpu and not allowed to be migrated on
* cpu unplug.
* HRTIMER_CB_IRQSAFE_UNLOCKED: Callback should run in hardirq context
* with timer->base lock unlocked
* used for timers which call wakeup to
* avoid lock order problems with rq->lock
*/
enum hrtimer_cb_mode {
HRTIMER_CB_SOFTIRQ,
HRTIMER_CB_IRQSAFE,
HRTIMER_CB_IRQSAFE_NO_RESTART,
HRTIMER_CB_IRQSAFE_NO_SOFTIRQ,
HRTIMER_CB_IRQSAFE_PERCPU,
HRTIMER_CB_IRQSAFE_UNLOCKED,
};
/*