From mboxrd@z Thu Jan 1 00:00:00 1970 From: Randy Dunlap Subject: Re: [RFC PATCH 22/23] watchdog/hardlockup/hpet: Only enable the HPET watchdog via a boot parameter Date: Wed, 13 Jun 2018 20:30:00 -0700 Message-ID: <2cde62b1-5218-0169-4f9d-1139f83a25c1@infradead.org> 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> <20180614005839.GA22358@voyager> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20180614005839.GA22358@voyager> Content-Language: en-US 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: Ricardo Neri 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 06/13/2018 05:58 PM, Ricardo Neri wrote: > 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? I think it's OK like it is. thanks, -- ~Randy