From mboxrd@z Thu Jan 1 00:00:00 1970 From: Prarit Bhargava Subject: Re: [patch 1/2] Ignore stolen time in the softlockup watchdog Date: Tue, 27 Mar 2007 12:53:22 -0400 Message-ID: <46094C02.9050702@redhat.com> References: <20070327053816.881735237@goop.org> <20070327054106.664262413@goop.org> <46092C9B.4030700@redhat.com> <46094861.7080400@goop.org> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <46094861.7080400@goop.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Jeremy Fitzhardinge Cc: Rick Lindsley , john stultz , Ingo Molnar , Linux Kernel , virtualization@lists.osdl.org, Paul Mackerras , Martin Schwidefsky , Thomas Gleixner , Andrew Morton List-Id: virtualization@lists.linuxfoundation.org Jeremy Fitzhardinge wrote: > Prarit Bhargava wrote: > = >> I'd like to see this patch implement/fix touch_cpu_softlockup_watchdog >> and touch_softlockup_watchdog to mimic touch_nmi_watchdog's behaviour. >> = > > Why? Is that more correct? It seems to me that you're interested in > whether a specific CPU has gone and locked up. If touching the watchdog > = > makes it update all CPU timestamps, then you'll hide the fact that other > CPUs have locked up, won't it? > > = In case of misuse, yes. But there are cases where we know that all CPUs = will have softlockup issues, such as when doing a "big" sysrq-t dump. = When doing the sysrq-t we take the tasklist_lock which prevents all = other CPUs from scheduling -- this leads to bogus softlockup messages, = so we need to reset everyone's watchdog just before releasing the = tasklist_lock. Another question -- are you going to expose disable/enable_watchdog to = other subsystems? Or are you going to expose touch_softlockup_watchdog? > J > =