From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Paul E. McKenney" Subject: Re: [PATCH v5 14/45] rcu, CPU hotplug: Fix comment referring to stop_machine() Date: Fri, 8 Feb 2013 16:14:39 -0800 Message-ID: <20130209001439.GQ2666@linux.vnet.ibm.com> References: <20130122073210.13822.50434.stgit@srivatsabhat.in.ibm.com> <20130122073630.13822.99359.stgit@srivatsabhat.in.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20130122073630.13822.99359.stgit@srivatsabhat.in.ibm.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: "Srivatsa S. Bhat" Cc: linux-doc@vger.kernel.org, peterz@infradead.org, fweisbec@gmail.com, linux-kernel@vger.kernel.org, mingo@kernel.org, linux-arch@vger.kernel.org, linux@arm.linux.org.uk, xiaoguangrong@linux.vnet.ibm.com, wangyun@linux.vnet.ibm.com, nikunj@linux.vnet.ibm.com, linux-pm@vger.kernel.org, rusty@rustcorp.com.au, rostedt@goodmis.org, rjw@sisk.pl, namhyung@kernel.org, tglx@linutronix.de, linux-arm-kernel@lists.infradead.org, netdev@vger.kernel.org, oleg@redhat.com, sbw@mit.edu, tj@kernel.org, akpm@linux-foundation.org, linuxppc-dev@lists.ozlabs.org List-Id: linux-arch.vger.kernel.org On Tue, Jan 22, 2013 at 01:06:34PM +0530, Srivatsa S. Bhat wrote: > Don't refer to stop_machine() in the CPU hotplug path, since we are going > to get rid of it. Also, move the comment referring to callback adoption > to the CPU_DEAD case, because that's where it happens now. > > Signed-off-by: Srivatsa S. Bhat Ouch! That comment is indeed obsolete and must die. I queued this to -rcu with your Signed-off-by. However, I omitted the added comment, as it is imcomplete -- it is easy to look at rcu_cleanup_dead_cpu() to see what it does. Thanx, Paul > --- > > kernel/rcutree.c | 9 ++++----- > 1 file changed, 4 insertions(+), 5 deletions(-) > > diff --git a/kernel/rcutree.c b/kernel/rcutree.c > index e441b77..ac94474 100644 > --- a/kernel/rcutree.c > +++ b/kernel/rcutree.c > @@ -2827,11 +2827,6 @@ static int __cpuinit rcu_cpu_notify(struct notifier_block *self, > break; > case CPU_DYING: > case CPU_DYING_FROZEN: > - /* > - * The whole machine is "stopped" except this CPU, so we can > - * touch any data without introducing corruption. We send the > - * dying CPU's callbacks to an arbitrarily chosen online CPU. > - */ > for_each_rcu_flavor(rsp) > rcu_cleanup_dying_cpu(rsp); > rcu_cleanup_after_idle(cpu); > @@ -2840,6 +2835,10 @@ static int __cpuinit rcu_cpu_notify(struct notifier_block *self, > case CPU_DEAD_FROZEN: > case CPU_UP_CANCELED: > case CPU_UP_CANCELED_FROZEN: > + /* > + * We send the dead CPU's callbacks to an arbitrarily chosen > + * online CPU. > + */ > for_each_rcu_flavor(rsp) > rcu_cleanup_dead_cpu(cpu, rsp); > break; > From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e31.co.us.ibm.com ([32.97.110.149]:50327 "EHLO e31.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1947420Ab3BIA2k (ORCPT ); Fri, 8 Feb 2013 19:28:40 -0500 Received: from /spool/local by e31.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 8 Feb 2013 17:28:39 -0700 Date: Fri, 8 Feb 2013 16:14:39 -0800 From: "Paul E. McKenney" Subject: Re: [PATCH v5 14/45] rcu, CPU hotplug: Fix comment referring to stop_machine() Message-ID: <20130209001439.GQ2666@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20130122073210.13822.50434.stgit@srivatsabhat.in.ibm.com> <20130122073630.13822.99359.stgit@srivatsabhat.in.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130122073630.13822.99359.stgit@srivatsabhat.in.ibm.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: "Srivatsa S. Bhat" Cc: tglx@linutronix.de, peterz@infradead.org, tj@kernel.org, oleg@redhat.com, rusty@rustcorp.com.au, mingo@kernel.org, akpm@linux-foundation.org, namhyung@kernel.org, rostedt@goodmis.org, wangyun@linux.vnet.ibm.com, xiaoguangrong@linux.vnet.ibm.com, rjw@sisk.pl, sbw@mit.edu, fweisbec@gmail.com, linux@arm.linux.org.uk, nikunj@linux.vnet.ibm.com, linux-pm@vger.kernel.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, netdev@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Message-ID: <20130209001439.exsnkXU0rCF7Zu8KwxJOGOp7Ycbv23bLaXlly2nrrQM@z> On Tue, Jan 22, 2013 at 01:06:34PM +0530, Srivatsa S. Bhat wrote: > Don't refer to stop_machine() in the CPU hotplug path, since we are going > to get rid of it. Also, move the comment referring to callback adoption > to the CPU_DEAD case, because that's where it happens now. > > Signed-off-by: Srivatsa S. Bhat Ouch! That comment is indeed obsolete and must die. I queued this to -rcu with your Signed-off-by. However, I omitted the added comment, as it is imcomplete -- it is easy to look at rcu_cleanup_dead_cpu() to see what it does. Thanx, Paul > --- > > kernel/rcutree.c | 9 ++++----- > 1 file changed, 4 insertions(+), 5 deletions(-) > > diff --git a/kernel/rcutree.c b/kernel/rcutree.c > index e441b77..ac94474 100644 > --- a/kernel/rcutree.c > +++ b/kernel/rcutree.c > @@ -2827,11 +2827,6 @@ static int __cpuinit rcu_cpu_notify(struct notifier_block *self, > break; > case CPU_DYING: > case CPU_DYING_FROZEN: > - /* > - * The whole machine is "stopped" except this CPU, so we can > - * touch any data without introducing corruption. We send the > - * dying CPU's callbacks to an arbitrarily chosen online CPU. > - */ > for_each_rcu_flavor(rsp) > rcu_cleanup_dying_cpu(rsp); > rcu_cleanup_after_idle(cpu); > @@ -2840,6 +2835,10 @@ static int __cpuinit rcu_cpu_notify(struct notifier_block *self, > case CPU_DEAD_FROZEN: > case CPU_UP_CANCELED: > case CPU_UP_CANCELED_FROZEN: > + /* > + * We send the dead CPU's callbacks to an arbitrarily chosen > + * online CPU. > + */ > for_each_rcu_flavor(rsp) > rcu_cleanup_dead_cpu(cpu, rsp); > break; >