From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756883Ab0EYJ5h (ORCPT ); Tue, 25 May 2010 05:57:37 -0400 Received: from 27.mail-out.ovh.net ([91.121.30.210]:41417 "HELO 27.mail-out.ovh.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1755313Ab0EYJ5f (ORCPT ); Tue, 25 May 2010 05:57:35 -0400 Message-ID: <4BFB9F0A.9040803@example.com> Date: Tue, 25 May 2010 11:57:30 +0200 From: Piotr Hosowicz Reply-To: piotr@hosowicz.com Organization: hosowicz.com User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100515 Icedove/3.0.4 MIME-Version: 1.0 To: Ingo Molnar CC: Peter Zijlstra , linux-kernel@vger.kernel.org, Jens Axboe , Divyesh Shah , Andrew Morton Subject: Re: BUG: using smp_processor_id() in preemptible [00000000] code: icedove-bin/5449 References: <4BF9EC69.5030709@example.com> <1274777422.5882.591.camel@twins> <20100525094347.GA7881@elte.hu> In-Reply-To: <20100525094347.GA7881@elte.hu> Content-Type: text/plain; charset=ISO-8859-2; format=flowed Content-Transfer-Encoding: 8bit X-Ovh-Tracer-Id: 11478549552176001520 X-Ovh-Remote: 83.6.191.44 (abbb44.neoplus.adsl.tpnet.pl) X-Ovh-Local: 213.186.33.20 (ns0.ovh.net) X-Spam-Check: DONE|U 0.5/N Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 25.05.2010 11:43, Ingo Molnar wrote: > This doesnt fix the whole issue. cpu_clock() is local, while the measurements > done in the blk code are global ... > > While the warning is fixed this way, the far more serious issue is still > there: time can go backwards if two points of time measurement are on > different CPUs and can mess up the statistics with negative values, etc... How serious is this? Can it damage my data? I ask because the machine is my private computer, not any test machine. Regards, Piotr Hosowicz -- Babcia rox! : alek: przyszli do mnie jechowi dzisiaj, otworzyła babcia pate_q: i co? alek: po 30 minutach rozmowy chcieli przejść na chrześcijaństwo NP: Alice In Chains - All Secrets Known NB: 2.6.34-20100524-1752