From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755455AbbEUI6k (ORCPT ); Thu, 21 May 2015 04:58:40 -0400 Received: from foss.arm.com ([217.140.101.70]:40728 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754067AbbEUI6L (ORCPT ); Thu, 21 May 2015 04:58:11 -0400 Date: Thu, 21 May 2015 09:58:06 +0100 From: Will Deacon To: "Paul E. McKenney" Cc: "linux-kernel@vger.kernel.org" , "mingo@kernel.org" , "laijs@cn.fujitsu.com" , "dipankar@in.ibm.com" , "akpm@linux-foundation.org" , "mathieu.desnoyers@efficios.com" , "josh@joshtriplett.org" , "tglx@linutronix.de" , "peterz@infradead.org" , "rostedt@goodmis.org" , "dhowells@redhat.com" , "edumazet@google.com" , "dvhart@linux.intel.com" , "fweisbec@gmail.com" , "oleg@redhat.com" , "bobby.prani@gmail.com" , "linux-arm-kernel@lists.infradead.org" , Catalin Marinas Subject: Re: [PATCH tip/core/rcu 7/9] arm64: Use common outgoing-CPU-notification code Message-ID: <20150521085806.GC21920@arm.com> References: <20150512214945.GA813@linux.vnet.ibm.com> <1431467407-1223-1-git-send-email-paulmck@linux.vnet.ibm.com> <1431467407-1223-7-git-send-email-paulmck@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1431467407-1223-7-git-send-email-paulmck@linux.vnet.ibm.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Paul, Sorry for being late on this one. On Tue, May 12, 2015 at 10:50:05PM +0100, Paul E. McKenney wrote: > From: "Paul E. McKenney" > > This commit removes the open-coded CPU-offline notification with new > common code. In particular, this change avoids calling scheduler code > using RCU from an offline CPU that RCU is ignoring. This is a minimal > change. A more intrusive change might invoke the cpu_check_up_prepare() > and cpu_set_state_online() functions at CPU-online time, which would > allow onlining throw an error if the CPU did not go offline properly. > > Signed-off-by: Paul E. McKenney > Cc: linux-arm-kernel@lists.infradead.org > Cc: Catalin Marinas > Cc: Will Deacon > --- > arch/arm64/kernel/smp.c | 6 ++---- > 1 file changed, 2 insertions(+), 4 deletions(-) I don't have a better idea, so: Acked-by: Will Deacon Is this queued via -tip already, or can we pick it into the arm64 tree for 4.2? Cheers, Will > diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c > index 2cb008177252..a899c1beff54 100644 > --- a/arch/arm64/kernel/smp.c > +++ b/arch/arm64/kernel/smp.c > @@ -253,15 +253,13 @@ static int op_cpu_kill(unsigned int cpu) > return cpu_ops[cpu]->cpu_kill(cpu); > } > > -static DECLARE_COMPLETION(cpu_died); > - > /* > * called on the thread which is asking for a CPU to be shutdown - > * waits until shutdown has completed, or it is timed out. > */ > void __cpu_die(unsigned int cpu) > { > - if (!wait_for_completion_timeout(&cpu_died, msecs_to_jiffies(5000))) { > + if (!cpu_wait_death(cpu, 5)) { > pr_crit("CPU%u: cpu didn't die\n", cpu); > return; > } > @@ -294,7 +292,7 @@ void cpu_die(void) > local_irq_disable(); > > /* Tell __cpu_die() that this CPU is now safe to dispose of */ > - complete(&cpu_died); > + (void)cpu_report_death(); > > /* > * Actually shutdown the CPU. This must never fail. The specific hotplug > -- > 1.8.1.5 >