From 7c1e76897492d92b6a1c2d6892494d39ded9680c Mon Sep 17 00:00:00 2001 From: Venkatesh Pallipadi Date: Wed, 3 Sep 2008 21:36:50 +0000 Subject: clockevents: prevent clockevent event_handler ending up handler_noop There is a ordering related problem with clockevents code, due to which clockevents_register_device() called after tickless/highres switch will not work. The new clockevent ends up with clockevents_handle_noop as event handler, resulting in no timer activity. The problematic path seems to be * old device already has hrtimer_interrupt as the event_handler * new clockevent device registers with a higher rating * tick_check_new_device() is called * clockevents_exchange_device() gets called * old->event_handler is set to clockevents_handle_noop * tick_setup_device() is called for the new device * which sets new->event_handler using the old->event_handler which is noop. Change the ordering so that new device inherits the proper handler. This does not have any issue in normal case as most likely all the clockevent devices are setup before the highres switch. But, can potentially be affecting some corner case where HPET force detect happens after the highres switch. This was a problem with HPET in MSI mode code that we have been experimenting with. Signed-off-by: Venkatesh Pallipadi Signed-off-by: Shaohua Li Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar --- include/linux/clockchips.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux') diff --git a/include/linux/clockchips.h b/include/linux/clockchips.h index c33b0dc28e4..ed3a5d473e5 100644 --- a/include/linux/clockchips.h +++ b/include/linux/clockchips.h @@ -127,6 +127,8 @@ extern int clockevents_register_notifier(struct notifier_block *nb); extern int clockevents_program_event(struct clock_event_device *dev, ktime_t expires, ktime_t now); +extern void clockevents_handle_noop(struct clock_event_device *dev); + #ifdef CONFIG_GENERIC_CLOCKEVENTS extern void clockevents_notify(unsigned long reason, void *arg); #else -- cgit v1.2.3 From dfb512ec4834116124da61d6c1ee10fd0aa32bd6 Mon Sep 17 00:00:00 2001 From: Max Krasnyansky Date: Fri, 29 Aug 2008 13:11:41 -0700 Subject: sched: arch_reinit_sched_domains() must destroy domains to force rebuild What I realized recently is that calling rebuild_sched_domains() in arch_reinit_sched_domains() by itself is not enough when cpusets are enabled. partition_sched_domains() code is trying to avoid unnecessary domain rebuilds and will not actually rebuild anything if new domain masks match the old ones. What this means is that doing echo 1 > /sys/devices/system/cpu/sched_mc_power_savings on a system with cpusets enabled will not take affect untill something changes in the cpuset setup (ie new sets created or deleted). This patch fixes restore correct behaviour where domains must be rebuilt in order to enable MC powersaving flags. Test on quad-core Core2 box with both CONFIG_CPUSETS and !CONFIG_CPUSETS. Also tested on dual-core Core2 laptop. Lockdep is happy and things are working as expected. Signed-off-by: Max Krasnyansky Tested-by: Vaidyanathan Srinivasan Signed-off-by: Ingo Molnar --- include/linux/cpuset.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h index e8f450c499b..2691926fb50 100644 --- a/include/linux/cpuset.h +++ b/include/linux/cpuset.h @@ -160,7 +160,7 @@ static inline int current_cpuset_is_being_rebound(void) static inline void rebuild_sched_domains(void) { - partition_sched_domains(0, NULL, NULL); + partition_sched_domains(1, NULL, NULL); } #endif /* !CONFIG_CPUSETS */ -- cgit v1.2.3