Re: [PREEMPT-RT] [PATCH] s390/cpum_sf: Remove superfluous SMP function call

Sebastian Andrzej Siewior
2016-04-05T11:13:11Z

On 04/05/2016 12:49 PM, Heiko Carstens wrote:
>> --- a/arch/s390/kernel/perf_cpum_sf.c
>> +++ b/arch/s390/kernel/perf_cpum_sf.c
>> @@ -1510,7 +1510,6 @@ static void cpumf_measurement_alert(stru
>> static int cpumf_pmu_notifier(struct notifier_block *self,
>> unsigned long action, void *hcpu)
>> {
>> - unsigned int cpu = (long) hcpu;
>> int flags;
>>
>> /* Ignore the notification if no events are scheduled on the PMU.
>> @@ -1523,11 +1522,15 @@ static int cpumf_pmu_notifier(struct not
>> case CPU_ONLINE:
>> case CPU_DOWN_FAILED:
>> flags = PMC_INIT;
>> - smp_call_function_single(cpu, setup_pmc_cpu, &flags, 1);
>> + local_irq_disable();
>> + setup_pmc_cpu(&flags);
>> + local_irq_enable();
>> break;
>
> ...but at least the CPU_DOWN_FAILED callback will not necessarily be called
> on the cpu that couldn't be brought offline.

I don't follow.

Sebastian