Messages in this thread | | | Date | Mon, 8 Mar 2010 19:27:08 +0100 | From | Oleg Nesterov <> | Subject | Re: [PATCH 2/4] stop_machine: reimplement using cpuhog |
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On 03/08, Heiko Carstens wrote: > > On Tue, Mar 09, 2010 at 12:53:21AM +0900, Tejun Heo wrote: > > > > diff --git a/arch/s390/kernel/time.c b/arch/s390/kernel/time.c > > index 65065ac..afe429e 100644 > > --- a/arch/s390/kernel/time.c > > +++ b/arch/s390/kernel/time.c > > @@ -397,7 +397,6 @@ static void __init time_init_wq(void) > > if (time_sync_wq) > > return; > > time_sync_wq = create_singlethread_workqueue("timesync"); > > - stop_machine_create(); > > } > > > > /* > > The reason we introduced stop_machine_create/destroy was to have a non-failing > variant that doesn't rely on I/O. > If we ever see a timesync machine check no I/O will succeed (it blocks) until > clocks have been synchronized. That means also that we rely on the non-blocking > semantics that those functions must have that are called via stop_machine. > This isn't true anymore with the cpu hog infrastructure: > if passed a blocking function that could wait on I/O we won't see any progress > anymore and the machine is dead.
Could you please spell?
How cpuhog can make a difference? Afaics, we shouldn't pass a blocking callback to hog_cpus/hog_one_cpu.
Oleg.
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