From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755388Ab2JPQi4 (ORCPT ); Tue, 16 Oct 2012 12:38:56 -0400 Received: from e28smtp05.in.ibm.com ([122.248.162.5]:54281 "EHLO e28smtp05.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754742Ab2JPQiL (ORCPT ); Tue, 16 Oct 2012 12:38:11 -0400 Message-ID: <507D8D3B.5000506@linux.vnet.ibm.com> Date: Tue, 16 Oct 2012 22:07:15 +0530 From: "Srivatsa S. Bhat" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:15.0) Gecko/20120828 Thunderbird/15.0 MIME-Version: 1.0 To: paulmck@linux.vnet.ibm.com CC: peterz@infradead.org, acme@ghostprotocols.net, mingo@kernel.org, tglx@linutronix.de, akpm@linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [RESEND PATCH 1/2] perf, cpu hotplug: Run CPU_STARTING notifiers with irqs disabled References: <20121016075809.3572.47848.stgit@srivatsabhat.in.ibm.com> <20121016163140.GA2385@linux.vnet.ibm.com> In-Reply-To: <20121016163140.GA2385@linux.vnet.ibm.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit x-cbid: 12101616-8256-0000-0000-0000049B1178 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/16/2012 10:01 PM, Paul E. McKenney wrote: > On Tue, Oct 16, 2012 at 01:28:10PM +0530, Srivatsa S. Bhat wrote: >> The CPU_STARTING notifiers are supposed to be run with irqs disabled. But the >> perf_cpu_notifier() macro invokes them without doing that. Fix it. > > Color me confused... Hehe, I believe the context provided by diff tricked you ;-) The function I am referring to is perf_cpu_notifier(), not perf_event_task_tick() :-) Regards, Srivatsa S. Bhat > Isn't perf_event_task_tick() invoked only > from scheduler_tick(), which always has interrupts disabled? > > Or are you needing to invoke it from somewhere else? > > Thanx, Paul > >> Signed-off-by: Srivatsa S. Bhat >> --- >> >> include/linux/perf_event.h | 3 +++ >> 1 file changed, 3 insertions(+) >> >> diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h >> index 2e90235..0647805 100644 >> --- a/include/linux/perf_event.h >> +++ b/include/linux/perf_event.h >> @@ -803,10 +803,13 @@ static inline void perf_event_task_tick(void) { } >> do { \ >> static struct notifier_block fn##_nb __cpuinitdata = \ >> { .notifier_call = fn, .priority = CPU_PRI_PERF }; \ >> + unsigned long flags; \ >> fn(&fn##_nb, (unsigned long)CPU_UP_PREPARE, \ >> (void *)(unsigned long)smp_processor_id()); \ >> + local_irq_save(flags); \ >> fn(&fn##_nb, (unsigned long)CPU_STARTING, \ >> (void *)(unsigned long)smp_processor_id()); \ >> + local_irq_restore(flags); \ >> fn(&fn##_nb, (unsigned long)CPU_ONLINE, \ >> (void *)(unsigned long)smp_processor_id()); \ >> register_cpu_notifier(&fn##_nb); \ >>