From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751592AbcBNQoI (ORCPT ); Sun, 14 Feb 2016 11:44:08 -0500 Received: from cdptpa-outbound-snat.email.rr.com ([107.14.166.225]:56943 "EHLO cdptpa-oedge-vip.email.rr.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751534AbcBNQoH (ORCPT ); Sun, 14 Feb 2016 11:44:07 -0500 Date: Sun, 14 Feb 2016 11:43:50 -0500 From: Steven Rostedt To: Denis Kirjanov Cc: linux-kernel@vger.kernel.org, paulmck@linux.vnet.ibm.com Subject: Re: [PATCH 2/2] tracing/rcu: don't trace rcu_callback on offline CPUs Message-ID: <20160214114350.1159e561@grimm.local.home> In-Reply-To: <1455387773-4245-2-git-send-email-kda@linux-powerpc.org> References: <1455387773-4245-1-git-send-email-kda@linux-powerpc.org> <1455387773-4245-2-git-send-email-kda@linux-powerpc.org> X-Mailer: Claws Mail 3.13.0 (GTK+ 2.24.29; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-RR-Connecting-IP: 107.14.168.142:25 X-Cloudmark-Score: 0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 13 Feb 2016 21:22:53 +0300 Denis Kirjanov wrote: > > diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h > index ef72c4a..5470f2f 100644 > --- a/include/trace/events/rcu.h > +++ b/include/trace/events/rcu.h > @@ -435,6 +435,8 @@ TRACE_EVENT(rcu_callback, > > TP_ARGS(rcuname, rhp, qlen_lazy, qlen), > > + TP_CONDITION(cpu_online(raw_smp_processor_id())), > + Besides the fact that this isn't a TRACE_EVENT_CONDITION, Isn't calling rcu_callback() dangerous from an offline CPU? Or is calling a callback from an offline CPU OK? Perhaps it is OK, as it doesn't need to worry about its current CPU, just the other CPUs. Paul? -- Steve > TP_STRUCT__entry( > __field(const char *, rcuname) > __field(void *, rhp)