From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752314AbaEVTzn (ORCPT ); Thu, 22 May 2014 15:55:43 -0400 Received: from mail.skyhub.de ([78.46.96.112]:50738 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751581AbaEVTzm (ORCPT ); Thu, 22 May 2014 15:55:42 -0400 Date: Thu, 22 May 2014 21:55:38 +0200 From: Borislav Petkov To: "Luck, Tony" Cc: Peter Zijlstra , "Srivatsa S. Bhat" , Srinivas Pandruvada , Jacob Pan , LKML , Borislav Petkov , Ingo Molnar , "Wysocki, Rafael J" , Thomas Gleixner , "ego@linux.vnet.ibm.com" , Oleg Nesterov Subject: Re: [PATCH] x86, MCE: Kill CPU_POST_DEAD Message-ID: <20140522195538.GM4383@pd.tnic> References: <1400750624-19238-1-git-send-email-bp@alien8.de> <537DC6D2.8040305@linux.vnet.ibm.com> <20140522100820.GE4383@pd.tnic> <537DE579.6000505@linux.vnet.ibm.com> <20140522123251.GU30445@twins.programming.kicks-ass.net> <20140522153006.GK4383@pd.tnic> <3908561D78D1C84285E8C5FCA982C28F328133C0@ORSMSX114.amr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <3908561D78D1C84285E8C5FCA982C28F328133C0@ORSMSX114.amr.corp.intel.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 On Thu, May 22, 2014 at 03:50:21PM +0000, Luck, Tony wrote: > >> So I think we can reduce it to just the one rwsem (with recursion) if we > >> shoot CPU_POST_DEAD in the head. > > > > Here's the first bullet. Stressing my box here with Steve's hotplug > > script seems to work fine. > > > > Tony, any objections? > > what was this comment referring to: > > /* intentionally ignoring frozen here */ > > After you move the cmci_rediscover() call, it is now in a place where we are > no longer ignoring frozen (i.e. the old placement did the rediscover even if the > CPU_TASKS_FROZEN bit was set - with the new placement we will skip rediscovery. > > So we were working around some interaction between cpu hotplug and frozen. > Do we no longer need to do that? Hmm, that FROZEN thing is supposedly for hotplug operations while suspend is happening. I guess it makes a little sense to rediscover CMCI banks while suspend is in progress. Whatever. Let's keep it before more crap ensues, that was a good catch, thanks. So, I guess something like that instead. Which means, I'd need to run a couple of suspend/resume rounds while hotplugging cores to see whether we're still kosher. More fun tomorrow. --- From: Borislav Petkov Date: Thu, 22 May 2014 16:40:54 +0200 Subject: [PATCH] x86, MCE: Kill CPU_POST_DEAD In conjunction with cleaning up CPU hotplug, we want to get rid of CPU_POST_DEAD. Kill this instance here and rediscover CMCI banks at the end of CPU_DEAD. Signed-off-by: Borislav Petkov --- arch/x86/kernel/cpu/mcheck/mce.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c index 68317c80de7f..bfde4871848f 100644 --- a/arch/x86/kernel/cpu/mcheck/mce.c +++ b/arch/x86/kernel/cpu/mcheck/mce.c @@ -2391,6 +2391,10 @@ mce_cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu) threshold_cpu_callback(action, cpu); mce_device_remove(cpu); mce_intel_hcpu_update(cpu); + + /* intentionally ignoring frozen here */ + if (!(action & CPU_TASKS_FROZEN)) + cmci_rediscover(); break; case CPU_DOWN_PREPARE: smp_call_function_single(cpu, mce_disable_cpu, &action, 1); @@ -2402,11 +2406,6 @@ mce_cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu) break; } - if (action == CPU_POST_DEAD) { - /* intentionally ignoring frozen here */ - cmci_rediscover(); - } - return NOTIFY_OK; } -- 1.9.0 -- Regards/Gruss, Boris. Sent from a fat crate under my desk. Formatting is fine. --