Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753600AbbDGRBa (ORCPT ); Tue, 7 Apr 2015 13:01:30 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:47227 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753210AbbDGRB0 (ORCPT ); Tue, 7 Apr 2015 13:01:26 -0400 Message-ID: <55240D40.6030206@oracle.com> Date: Tue, 07 Apr 2015 13:00:48 -0400 From: Sasha Levin User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 MIME-Version: 1.0 To: Ingo Molnar , Michal Hocko CC: Borislav Petkov , Linus Torvalds , LKML , Rusty Russell , Dave Jones , the arch/x86 maintainers Subject: Re: Hang on large copy_from_user with PREEMPT_NONE References: <552204B8.40605@oracle.com> <5522D9A8.5080104@oracle.com> <20150407093145.GA10348@gmail.com> <20150407103955.GB14095@pd.tnic> <20150407110531.GA14136@gmail.com> <20150407143009.GG7935@dhcp22.suse.cz> <20150407143710.GA18777@gmail.com> In-Reply-To: <20150407143710.GA18777@gmail.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit X-Source-IP: aserv0021.oracle.com [141.146.126.233] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1163 Lines: 36 On 04/07/2015 10:37 AM, Ingo Molnar wrote: > > * Michal Hocko wrote: > >> On Tue 07-04-15 13:05:31, Ingo Molnar wrote: >>> >>> * Borislav Petkov wrote: >>> >>>> On Tue, Apr 07, 2015 at 11:31:45AM +0200, Ingo Molnar wrote: >>>>> Would be nice to see the actual kernel .config, as there's a few >>>>> debug features that can slow things down significantly, such as >>>>> CONFIG_KMEMCHECK=y or in some cases CONFIG_DEBUG_PAGEALLOC=y. >>>> >>>> He sent it here: https://lkml.kernel.org/r/55229D7E.6080309@oracle.com >>>> >>>> I'm attaching it again. >>> >>> Thanks. Nothing particularly expensive stands out to me at a quick >>> glance:-/ >> >> Sasha uses KASAN very often and it is enabled here as well. I guess >> this might slow things really down. > > Indeed, that kind of instrumentation might explain the overhead ... It locks up quickly without KASan as well. Thanks, Sasha -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/