Messages in this thread | | | Date | Tue, 5 Apr 2016 12:49:12 +0200 | From | Heiko Carstens <> | Subject | Re: [PATCH] s390/cpum_sf: Remove superfluous SMP function call |
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On Mon, Apr 04, 2016 at 12:27:20PM +0200, Anna-Maria Gleixner wrote: > Since commit 1cf4f629d9d2 ("cpu/hotplug: Move online calls to > hotplugged cpu") it is ensured that callbacks of CPU_ONLINE and > CPU_DOWN_PREPARE are processed on the hotplugged CPU. Due to this SMP > function calls are no longer required. > > Replace smp_call_function_single() with a direct call of > setup_pmc_cpu(). To keep the calling convention, interrupts are > explicitely disabled around the call. > > Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> > Cc: Heiko Carstens <heiko.carstens@de.ibm.com> > Cc: linux-s390@vger.kernel.org > Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de> > --- > arch/s390/kernel/perf_cpum_sf.c | 9 ++++++--- > 1 file changed, 6 insertions(+), 3 deletions(-) > > --- 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.
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