From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758845Ab3IBPv4 (ORCPT ); Mon, 2 Sep 2013 11:51:56 -0400 Received: from fold.natur.cuni.cz ([195.113.57.32]:37133 "EHLO fold.natur.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758760Ab3IBPvz (ORCPT ); Mon, 2 Sep 2013 11:51:55 -0400 Message-ID: <5224B3F5.8090402@gmail.com> Date: Mon, 02 Sep 2013 17:51:17 +0200 From: =?UTF-8?B?TWFydGluIE1PS1JFSsWg?= User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:23.0) Gecko/20100101 Firefox/23.0 SeaMonkey/2.20 MIME-Version: 1.0 To: Catalin Marinas , Max Filippov CC: LKML Subject: Re: 3.10.9: kmemleak disables all CPUs except CPU0 References: <5221F119.4070000@gmail.com> <20130902154840.GC13871@arm.com> In-Reply-To: <20130902154840.GC13871@arm.com> X-Enigmail-Version: 1.5.2 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Catalin Marinas wrote: > On Mon, Sep 02, 2013 at 04:44:52PM +0100, Max Filippov wrote: >> On Mon, Sep 2, 2013 at 7:31 PM, Catalin Marinas wrote: >>> On 31 August 2013 14:35, Martin MOKREJŠ wrote: >>>> never realized that my CPUs are gone if I compile into kernel kmemleak. >>>> Is that really the aim? >>>> >>>> CONFIG_HAVE_DEBUG_KMEMLEAK=y >>>> CONFIG_DEBUG_KMEMLEAK=y >>>> CONFIG_DEBUG_KMEMLEAK_EARLY_LOG_SIZE=400 >>>> # CONFIG_DEBUG_KMEMLEAK_TEST is not set >>>> # CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF is not set >>>> >>>> 1. Why isn't there /sys/devices/system/cpu/cpu0/online file? >>>> Does not matter if it contains 0 or 1. It just should exist. >>> >>> I can't really see how kmemleak would do this, maybe other config >>> options that get set/cleared in the process of selecting kmemleak. Can >> >> Seems to be kmemcheck: from arch/x86/mm/kmemcheck/kmemcheck.c: >> >> int __init kmemcheck_init(void) >> { >> #ifdef CONFIG_SMP >> /* >> * Limit SMP to use a single CPU. We rely on the fact that this code >> * runs before SMP is set up. >> */ >> if (setup_max_cpus > 1) { >> printk(KERN_INFO >> "kmemcheck: Limiting number of CPUs to 1.\n"); >> setup_max_cpus = 1; >> } >> #endif > > Ah, ok, not my problem then ;) Fine, so would somebody please update the help text accessible in "menuconfig" for this entry? It should be clear that it has a huge performance impact if enabled. And, by compiling in it is enabled by default. Thank you Martin