From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ricardo Neri Subject: Re: [RFC PATCH 22/23] watchdog/hardlockup/hpet: Only enable the HPET watchdog via a boot parameter Date: Wed, 13 Jun 2018 17:58:39 -0700 Message-ID: <20180614005839.GA22358@voyager> References: <1528851463-21140-1-git-send-email-ricardo.neri-calderon@linux.intel.com> <1528851463-21140-23-git-send-email-ricardo.neri-calderon@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Randy Dunlap Cc: "Rafael J. Wysocki" , Peter Zijlstra , Alexei Starovoitov , Kai-Heng Feng , "H. Peter Anvin" , sparclinux-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Ingo Molnar , Christoffer Dall , Davidlohr Bueso , Ashok Raj , Michael Ellerman , x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, David Rientjes , Andi Kleen , Waiman Long , Borislav Petkov , Masami Hiramatsu , Don Zickus , "Ravi V. Shankar" , Konrad Rzeszutek Wilk , Marc Zyngier , Frederic Weisbecker , Nicholas Piggin List-Id: iommu@lists.linux-foundation.org On Tue, Jun 12, 2018 at 10:26:57PM -0700, Randy Dunlap wrote: > On 06/12/2018 05:57 PM, Ricardo Neri wrote: > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > > index f2040d4..a8833c7 100644 > > --- a/Documentation/admin-guide/kernel-parameters.txt > > +++ b/Documentation/admin-guide/kernel-parameters.txt > > @@ -2577,7 +2577,7 @@ > > Format: [state][,regs][,debounce][,die] > > > > nmi_watchdog= [KNL,BUGS=X86] Debugging features for SMP kernels > > - Format: [panic,][nopanic,][num] > > + Format: [panic,][nopanic,][num,][hpet] > > Valid num: 0 or 1 > > 0 - turn hardlockup detector in nmi_watchdog off > > 1 - turn hardlockup detector in nmi_watchdog on > > This says that I can use "nmi_watchdog=hpet" without using 0 or 1. > Is that correct? Yes, this what I meant. In my view, if you set nmi_watchdog=hpet it implies that you want to activate the NMI watchdog. In this case, perf. I can see how this will be ambiguous for the case of perf and arch NMI watchdogs. Alternative, a new parameter could be added; such as nmi_watchdog_type. I didn't want to add it in this patchset as I think that a single parameter can handle the enablement and type of the NMI watchdog. What do you think? Thanks and BR, Ricardo From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 415lhv6h52zF11V for ; Thu, 14 Jun 2018 11:02:38 +1000 (AEST) Date: Wed, 13 Jun 2018 17:58:39 -0700 From: Ricardo Neri To: Randy Dunlap Cc: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Andi Kleen , Ashok Raj , Borislav Petkov , Tony Luck , "Ravi V. Shankar" , x86@kernel.org, sparclinux@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, Jacob Pan , "Rafael J. Wysocki" , Don Zickus , Nicholas Piggin , Michael Ellerman , Frederic Weisbecker , Alexei Starovoitov , Babu Moger , Mathieu Desnoyers , Masami Hiramatsu , Peter Zijlstra , Andrew Morton , Philippe Ombredanne , Colin Ian King , Byungchul Park , "Paul E. McKenney" , "Luis R. Rodriguez" , Waiman Long , Josh Poimboeuf , Davidlohr Bueso , Christoffer Dall , Marc Zyngier , Kai-Heng Feng , Konrad Rzeszutek Wilk , David Rientjes , iommu@lists.linux-foundation.org Subject: Re: [RFC PATCH 22/23] watchdog/hardlockup/hpet: Only enable the HPET watchdog via a boot parameter Message-ID: <20180614005839.GA22358@voyager> References: <1528851463-21140-1-git-send-email-ricardo.neri-calderon@linux.intel.com> <1528851463-21140-23-git-send-email-ricardo.neri-calderon@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, Jun 12, 2018 at 10:26:57PM -0700, Randy Dunlap wrote: > On 06/12/2018 05:57 PM, Ricardo Neri wrote: > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > > index f2040d4..a8833c7 100644 > > --- a/Documentation/admin-guide/kernel-parameters.txt > > +++ b/Documentation/admin-guide/kernel-parameters.txt > > @@ -2577,7 +2577,7 @@ > > Format: [state][,regs][,debounce][,die] > > > > nmi_watchdog= [KNL,BUGS=X86] Debugging features for SMP kernels > > - Format: [panic,][nopanic,][num] > > + Format: [panic,][nopanic,][num,][hpet] > > Valid num: 0 or 1 > > 0 - turn hardlockup detector in nmi_watchdog off > > 1 - turn hardlockup detector in nmi_watchdog on > > This says that I can use "nmi_watchdog=hpet" without using 0 or 1. > Is that correct? Yes, this what I meant. In my view, if you set nmi_watchdog=hpet it implies that you want to activate the NMI watchdog. In this case, perf. I can see how this will be ambiguous for the case of perf and arch NMI watchdogs. Alternative, a new parameter could be added; such as nmi_watchdog_type. I didn't want to add it in this patchset as I think that a single parameter can handle the enablement and type of the NMI watchdog. What do you think? Thanks and BR, Ricardo From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ricardo Neri Date: Thu, 14 Jun 2018 00:58:39 +0000 Subject: Re: [RFC PATCH 22/23] watchdog/hardlockup/hpet: Only enable the HPET watchdog via a boot parameter Message-Id: <20180614005839.GA22358@voyager> List-Id: References: <1528851463-21140-1-git-send-email-ricardo.neri-calderon@linux.intel.com> <1528851463-21140-23-git-send-email-ricardo.neri-calderon@linux.intel.com> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Randy Dunlap Cc: "Rafael J. Wysocki" , Peter Zijlstra , Alexei Starovoitov , Kai-Heng Feng , "H. Peter Anvin" , sparclinux-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Ingo Molnar , Christoffer Dall , Davidlohr Bueso , Ashok Raj , Michael Ellerman , x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, David Rientjes , Andi Kleen , Waiman Long , Borislav Petkov , Masami Hiramatsu , Don Zickus , "Ravi V. Shankar" , Konrad Rzeszutek Wilk , Marc Zyngier , Frederic Weisbecker , Nicholas Piggin On Tue, Jun 12, 2018 at 10:26:57PM -0700, Randy Dunlap wrote: > On 06/12/2018 05:57 PM, Ricardo Neri wrote: > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > > index f2040d4..a8833c7 100644 > > --- a/Documentation/admin-guide/kernel-parameters.txt > > +++ b/Documentation/admin-guide/kernel-parameters.txt > > @@ -2577,7 +2577,7 @@ > > Format: [state][,regs][,debounce][,die] > > > > nmi_watchdog= [KNL,BUGS=X86] Debugging features for SMP kernels > > - Format: [panic,][nopanic,][num] > > + Format: [panic,][nopanic,][num,][hpet] > > Valid num: 0 or 1 > > 0 - turn hardlockup detector in nmi_watchdog off > > 1 - turn hardlockup detector in nmi_watchdog on > > This says that I can use "nmi_watchdog=hpet" without using 0 or 1. > Is that correct? Yes, this what I meant. In my view, if you set nmi_watchdog=hpet it implies that you want to activate the NMI watchdog. In this case, perf. I can see how this will be ambiguous for the case of perf and arch NMI watchdogs. Alternative, a new parameter could be added; such as nmi_watchdog_type. I didn't want to add it in this patchset as I think that a single parameter can handle the enablement and type of the NMI watchdog. What do you think? Thanks and BR, Ricardo