From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751438Ab3LLEu4 (ORCPT ); Wed, 11 Dec 2013 23:50:56 -0500 Received: from terminus.zytor.com ([198.137.202.10]:42911 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751028Ab3LLEuw (ORCPT ); Wed, 11 Dec 2013 23:50:52 -0500 Message-ID: <52A94065.1050103@zytor.com> Date: Wed, 11 Dec 2013 20:49:41 -0800 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.1.0 MIME-Version: 1.0 To: Mike Galbraith CC: Borislav Petkov , Ingo Molnar , Peter Zijlstra , Thomas Gleixner , Len Brown , Linux PM list , "linux-kernel@vger.kernel.org" , Jeremy Eder , x86@kernel.org Subject: Re: 50 Watt idle power regression bisected to Linux-3.10 References: <20131211113839.GF21683@pd.tnic> <20131211115239.GA21999@twins.programming.kicks-ass.net> <1386764955.12005.60.camel@marge.simpson.net> <20131211124352.GB21999@twins.programming.kicks-ass.net> <20131211134048.GH21683@pd.tnic> <20131211145655.GB4510@gmail.com> <20131211164318.GA2480@laptop.programming.kicks-ass.net> <20131211175036.GC12431@gmail.com> <52A8F073.9040500@zytor.com> <20131211231425.GD8863@pd.tnic> <52A908DB.60902@zytor.com> <1386822357.6056.12.camel@marge.simpson.net> In-Reply-To: <1386822357.6056.12.camel@marge.simpson.net> X-Enigmail-Version: 1.6 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/11/2013 08:25 PM, Mike Galbraith wrote: > arch/x86/include/asm/mwait.h | 4 ++-- > arch/x86/kernel/cpu/common.c | 7 ++++--- > arch/x86/kernel/setup_percpu.c | 1 + > 3 files changed, 7 insertions(+), 5 deletions(-) > > Index: linux-2.6/arch/x86/kernel/cpu/common.c > =================================================================== > --- linux-2.6.orig/arch/x86/kernel/cpu/common.c > +++ linux-2.6/arch/x86/kernel/cpu/common.c > @@ -65,13 +65,14 @@ void __init setup_cpu_local_masks(void) > } > > /* allocate percpu area for mwait doorbell */ > -char __percpu *mwait_doorbell; > +DEFINE_PER_CPU(char *, mwait_doorbell); > +EXPORT_PER_CPU_SYMBOL(mwait_doorbell); > Sorry, this is wrong. This is NOT a percpu variable, it is a pointer to a percpu allocation, but the variable itself is not a percpu variable. This explains your boom. > void __init setup_mwait_doorbell(void) > { > if (boot_cpu_has(X86_FEATURE_MWAIT)) { > - mwait_doorbell = __alloc_percpu(boot_cpu_data.clflush_size, > - boot_cpu_data.clflush_size); > + mwait_doorbell = __alloc_percpu(boot_cpu_data.x86_clflush_size, > + boot_cpu_data.x86_clflush_size); > > if (!mwait_doorbell) { > /* This should never happen... */ -hpa