From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Tue, 5 Apr 2016 12:49:54 +0200 From: Heiko Carstens Subject: Re: [PATCH] s390/cpum_cf: Remove superfluous SMP function call Message-ID: <20160405104954.GD3937@osiris> References: <1459765665-13649-1-git-send-email-anna-maria@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1459765665-13649-1-git-send-email-anna-maria@linutronix.de> Sender: linux-kernel-owner@vger.kernel.org List-Archive: List-Post: To: Anna-Maria Gleixner Cc: linux-kernel@vger.kernel.org, rt@linutronix.de, Martin Schwidefsky , linux-s390@vger.kernel.org List-ID: On Mon, Apr 04, 2016 at 12:27:45PM +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 > Cc: Heiko Carstens > Cc: linux-s390@vger.kernel.org > Signed-off-by: Anna-Maria Gleixner > --- > arch/s390/kernel/perf_cpum_cf.c | 9 ++++++--- > 1 file changed, 6 insertions(+), 3 deletions(-) > > --- a/arch/s390/kernel/perf_cpum_cf.c > +++ b/arch/s390/kernel/perf_cpum_cf.c > @@ -665,18 +665,21 @@ static struct pmu cpumf_pmu = { > static int cpumf_pmu_notifier(struct notifier_block *self, unsigned long action, > void *hcpu) > { > - unsigned int cpu = (long) hcpu; > int flags; > > switch (action & ~CPU_TASKS_FROZEN) { > 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; Same issue about CPU_DOWN_FAILED here.