From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-x244.google.com (mail-pg0-x244.google.com [IPv6:2607:f8b0:400e:c05::244]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3wTRfr3pRBzDqb7 for ; Fri, 19 May 2017 09:07:48 +1000 (AEST) Received: by mail-pg0-x244.google.com with SMTP id h64so7447778pge.3 for ; Thu, 18 May 2017 16:07:48 -0700 (PDT) Date: Fri, 19 May 2017 09:07:31 +1000 From: Nicholas Piggin To: Don Zickus Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, adi-buildroot-devel@lists.sourceforge.net, linux-am33-list@redhat.com, sparclinux@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, uobergfe@redhat.com Subject: Re: [RFC] arch hardlockup detector interfaces improvement Message-ID: <20170519090731.1e49cd0d@roar.ozlabs.ibm.com> In-Reply-To: <20170518163028.tf2llimuo4l4l5nv@redhat.com> References: <20170518155026.23799-1-npiggin@gmail.com> <20170518163028.tf2llimuo4l4l5nv@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Thu, 18 May 2017 12:30:28 -0400 Don Zickus wrote: > (adding Uli) > > On Fri, May 19, 2017 at 01:50:26AM +1000, Nicholas Piggin wrote: > > I'd like to make it easier for architectures that have their own NMI / > > hard lockup detector to reuse various configuration interfaces that are > > provided by generic detectors (cmdline, sysctl, suspend/resume calls). > > > > I'd also like to remove the dependency of arch hard lockup detectors > > on the softlockup detector. The reason being these watchdogs can be > > very small (sparc's is like a page of core code that does not use any > > big subsystem like kthreads or timers). > > > > So I do this by adding a separate CONFIG_SOFTLOCKUP_DETECTOR, and > > juggling around what goes under config options. HAVE_NMI_WATCHDOG > > continues to be the config for arch to override the hard lockup > > detector, which is expanded to cover a few more cases. > > Basically you are trying to remove the heavy HARDLOCKUP pieces to minimize > the SOFTLOCKUP piece and use your own NMI detector, right? > > I am guessing you would then disable SOFTLOCKUP to remove all the kthread > and timer stuff but continue to use the generic infrastructure to help > manager your own NMI detector? Yes that's right. > A lot of the code is just re-organizing things and adding an explicit > ifdef on SOFTLOCKUP, which seems fine to me. > > I just need to spend some time on some of your #else clauses to see what > functionality is dropped when you use your approach. Okay, appreciated. I can trim down cc lists and send you my powerpc WIP if you'd like to have a look. Thanks, Nick