Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754142AbbDGOhS (ORCPT ); Tue, 7 Apr 2015 10:37:18 -0400 Received: from mail-wg0-f53.google.com ([74.125.82.53]:33874 "EHLO mail-wg0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750966AbbDGOhP (ORCPT ); Tue, 7 Apr 2015 10:37:15 -0400 Date: Tue, 7 Apr 2015 16:37:10 +0200 From: Ingo Molnar To: Michal Hocko Cc: Borislav Petkov , Linus Torvalds , Sasha Levin , LKML , Rusty Russell , Dave Jones , the arch/x86 maintainers Subject: Re: Hang on large copy_from_user with PREEMPT_NONE Message-ID: <20150407143710.GA18777@gmail.com> 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150407143009.GG7935@dhcp22.suse.cz> 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 Content-Length: 1078 Lines: 32 * 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 ... Thanks, Ingo -- 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/