On Thu, Oct 14, 2010 at 9:50 PM, Arjan van de Ven <[email protected]> wrote: > On 10/14/2010 11:27 AM, richard -rw- weinberger wrote: >> >> Hi Arjan! >> >> This commit causes some problems on UML. >> > that is extremely weird. >> >> The kernel freezes after a few seconds until it gets some input. >> e.g: When I run top it stops refreshing the process list until i press a >> button. > > a slab timer change (to not be as critical) causing global timer issues.... > that's very obviously not a problem with this patch. > has this been seem anywhere except UML ?
A small update: It seems that CONFIG_NO_HZ is broken on UML. :-( CONFIG_NO_HZ + CONFIG_SLAB: works CONFIG_NO_HZ + CONFIG_SLAB + your patch: broken CONFIG_NO_HZ + CONFIG_SLUB: broken CONFIG_SLAB + your patch: works CONFIG_SLAB: works CONFIG_SLUB: works >> Messages like this appear: >> INFO: rcu_sched_state detected stall on CPU 0 (t=7348 jiffies) >> >> After reverting UML works fine again. >> >> commit 78b435368fcd615e695a06012cd963a556284e00 >> Author: Arjan van de Ven<[email protected]> >> Date: Mon Jul 19 10:59:42 2010 -0700 >> >> slab: use deferable timers for its periodic housekeeping >> >> slab has a "once every 2 second" timer for its housekeeping. >> As the number of logical processors is growing, its more and more >> common that this 2 second timer becomes the primary wakeup source. >> >> This patch turns this housekeeping timer into a deferable timer, >> which means that the timer does not interrupt idle, but just runs >> at the next event that wakes the cpu up. >> >> The impact is that the timer likely runs a bit later, but during the >> delay no code is running so there's not all that much reason for >> a difference in housekeeping to occur because of this delay. >> >> Signed-off-by: Arjan van de Ven<[email protected]> >> Signed-off-by: Pekka Enberg<[email protected]> >> >> diff --git a/mm/slab.c b/mm/slab.c >> index e49f8f4..29aad44 100644 >> --- a/mm/slab.c >> +++ b/mm/slab.c >> @@ -861,7 +861,7 @@ static void __cpuinit start_cpu_timer(int cpu) >> */ >> if (keventd_up()&& reap_work->work.func == NULL) { >> init_reap_node(cpu); >> - INIT_DELAYED_WORK(reap_work, cache_reap); >> + INIT_DELAYED_WORK_DEFERRABLE(reap_work, cache_reap); >> schedule_delayed_work_on(cpu, reap_work, >> __round_jiffies_relative(HZ, >> cpu)); >> } >> >> > > -- Thanks, //richard ------------------------------------------------------------------------------ Download new Adobe(R) Flash(R) Builder(TM) 4 The new Adobe(R) Flex(R) 4 and Flash(R) Builder(TM) 4 (formerly Flex(R) Builder(TM)) enable the development of rich applications that run across multiple browsers and platforms. Download your free trials today! http://p.sf.net/sfu/adobe-dev2dev _______________________________________________ User-mode-linux-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel
