From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755447Ab3KEVlJ (ORCPT ); Tue, 5 Nov 2013 16:41:09 -0500 Received: from terminus.zytor.com ([198.137.202.10]:39720 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754728Ab3KEVlH (ORCPT ); Tue, 5 Nov 2013 16:41:07 -0500 User-Agent: K-9 Mail for Android In-Reply-To: <20131105202855.GD4598@redhat.com> References: <1383642967-12595-1-git-send-email-bhe@redhat.com> <20131105202855.GD4598@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Subject: Re: [PATCH] x86: make reboot task only run on the appropriate processor From: "H. Peter Anvin" Date: Tue, 05 Nov 2013 13:39:49 -0800 To: Vivek Goyal , Baoquan He CC: linux-kernel@vger.kernel.org, tglx@linutronix.de, mingo@redhat.com, x86@kernel.org, akpm@linux-foundation.org, holt@sgi.com, davej@fedoraproject.org, rmk+kernel@arm.linux.org.uk, chaowang@redhat.com, mwhitehe@redhat.com, kexec@lists.infradead.org Message-ID: <6b2e54d6-effa-4884-b674-2692a67e5cbc@email.android.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We should, yes, if cpu 0 is available. Vivek Goyal wrote: >On Tue, Nov 05, 2013 at 05:16:07PM +0800, Baoquan He wrote: >> Currently system always reboot after below message when execute >"kexec -e". >> >> [ 0.572119] smpboot: Booting Node 0, Processors # 1 OK >> > >So is it same problem were we reboot on non-boot cpu and sending INIT >to boot cpu in second kernel brings down the machine? > >I think for x86, it makes sense to reboot on boot cpu. > >Thanks >Vivek > >> In commit 1b3a5d02ee070c8f9943333b9b6370f486601e0f, reboot= handling >was >> moved to kerne/reboot.c. However, the code to migrate current thread >to >> reboot cpu was removed. That cause this incorrect kexec behavior. >> >> Now add that code block back. >> >> Reported-by: Matthew Whitehead >> Reported-by: Dave Young >> Tested-by: WANG Chao >> Signed-off-by: Baoquan He >> --- >> arch/x86/kernel/reboot.c | 15 +++++++++++++++ >> 1 file changed, 15 insertions(+) >> >> diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c >> index 7e920bf..3049de9 100644 >> --- a/arch/x86/kernel/reboot.c >> +++ b/arch/x86/kernel/reboot.c >> @@ -551,6 +551,21 @@ void native_machine_shutdown(void) >> { >> /* Stop the cpus and apics */ >> #ifdef CONFIG_SMP >> + /* The boot cpu is always logical cpu 0 */ >> + int reboot_cpu_id = 0; >> + >> + /* See if there has been given a command line override */ >> + if ((reboot_cpu != -1) && (reboot_cpu < nr_cpu_ids) && >> + cpu_online(reboot_cpu)) >> + reboot_cpu_id = reboot_cpu; >> + >> + /* Make certain the cpu I'm about to reboot on is online */ >> + if (!cpu_online(reboot_cpu_id)) >> + reboot_cpu_id = smp_processor_id(); >> + >> + /* Make certain I only run on the appropriate processor */ >> + set_cpus_allowed_ptr(current, cpumask_of(reboot_cpu_id)); >> + >> /* >> * Stop all of the others. Also disable the local irq to >> * not receive the per-cpu timer interrupt which may trigger >> -- >> 1.8.3.1 -- Sent from my mobile phone. Please pardon brevity and lack of formatting.