From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932659AbeCOPya (ORCPT ); Thu, 15 Mar 2018 11:54:30 -0400 Received: from mail-wm0-f66.google.com ([74.125.82.66]:53356 "EHLO mail-wm0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932395AbeCOPy0 (ORCPT ); Thu, 15 Mar 2018 11:54:26 -0400 X-Google-Smtp-Source: AG47ELtl4WWeVCL7n+27UcYhBW2/7g1NFrrUY0JnU8VccwdIU3q13I3buqpaX+ttwX01aUWpUzXRfw== Message-ID: <1521129262.2686.23.camel@arista.com> Subject: Re: [PATCHv3] iommu/intel: Ratelimit each dmar fault printing From: Dmitry Safonov To: Joerg Roedel Cc: linux-kernel@vger.kernel.org, 0x7f454c46@gmail.com, Alex Williamson , David Woodhouse , Ingo Molnar , Lu Baolu , iommu@lists.linux-foundation.org Date: Thu, 15 Mar 2018 15:54:22 +0000 In-Reply-To: <20180315152828.GA11365@8bytes.org> References: <20180215191729.15777-1-dima@arista.com> <20180315134649.skh2aukcmg5ud74y@8bytes.org> <1521123183.2686.7.camel@arista.com> <20180315142253.GC5259@8bytes.org> <1521124490.2686.16.camel@arista.com> <1521124920.2686.20.camel@arista.com> <20180315152828.GA11365@8bytes.org> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.24.6 (3.24.6-1.fc26) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2018-03-15 at 16:28 +0100, Joerg Roedel wrote: > On Thu, Mar 15, 2018 at 02:42:00PM +0000, Dmitry Safonov wrote: > > But even with loop-limit we will need ratelimit each printk() > > *also*. > > Otherwise loop-limit will be based on time spent printing, not on > > anything else.. > > The patch makes sense even with loop-limit in my opinion. > > Looks like I mis-read your patch, somehow it looked to me as if you > replace all 'ratelimited' usages with a call to __ratelimit(), but > you > just move 'ratelimited' into the loop, which actually makes sense. Oh, ok > But still, this alone is no proper fix for the soft-lockups you are > seeing. Well, I can also limit number of loops with say cap_num_fault_regs(). I didn't do that as on my measures the time spent on clearing a fault is so small, that I'm not sure if it's possible to stuck in this loop. -- Thanks, Dmitry