* Colin Cross <[email protected]> [130110 14:37]: > On Thu, Jan 10, 2013 at 12:38 PM, Tony Lindgren <[email protected]> wrote: > > > > * Colin Cross <[email protected]> [130109 18:05]: > > > +static void watchdog_check_hardlockup_other_cpu(void) > > > +{ > > > + int cpu; > > > + cpumask_t cpus = watchdog_cpus; > > > + > > > + /* > > > + * Test for hardlockups every 3 samples. The sample period is > > > + * watchdog_thresh * 2 / 5, so 3 samples gets us back to slightly > > > over > > > + * watchdog_thresh (over by 20%). > > > + */ > > > + if (__this_cpu_read(hrtimer_interrupts) % 3 != 0) > > > + return; > > > + > > > + /* check for a hardlockup on the next cpu */ > > > + cpu = cpumask_next(smp_processor_id(), &cpus); > > > > Hmm don't you want to check cpu_oneline_mask here and > > return if the other CPU is offline? > > watchdog_cpus is effectively a local copy of cpu_online_mask, but > updated after the watchdog_nmi_touch in watchdog_nmi_enable. This > avoids a false positive after hotplugging in a cpu when > cpu_online_mask is true but that cpu hasn't yet run it's first > hrtimer.
OK thanks for clarifying that. Tony -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
