From mboxrd@z Thu Jan 1 00:00:00 1970 From: Glauber Costa Subject: [RFC v2 6/7] touch softlockup watchdog Date: Mon, 30 Aug 2010 12:06:28 -0400 Message-ID: <1283184391-7785-13-git-send-email-glommer@redhat.com> References: <1283184391-7785-1-git-send-email-glommer@redhat.com> <1283184391-7785-2-git-send-email-glommer@redhat.com> <1283184391-7785-3-git-send-email-glommer@redhat.com> <1283184391-7785-4-git-send-email-glommer@redhat.com> <1283184391-7785-5-git-send-email-glommer@redhat.com> <1283184391-7785-6-git-send-email-glommer@redhat.com> <1283184391-7785-7-git-send-email-glommer@redhat.com> <1283184391-7785-8-git-send-email-glommer@redhat.com> <1283184391-7785-9-git-send-email-glommer@redhat.com> <1283184391-7785-10-git-send-email-glommer@redhat.com> <1283184391-7785-11-git-send-email-glommer@redhat.com> <1283184391-7785-12-git-send-email-glommer@redhat.com> Cc: avi@redhat.com, zamsden@redhat.com, mtosatti@redhat.com, riel@redhat.com, peterz@infradead.org, mingo@elte.hu, jeremy@goop.org To: kvm@vger.kernel.org Return-path: Received: from mx1.redhat.com ([209.132.183.28]:6633 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755917Ab0H3QX6 (ORCPT ); Mon, 30 Aug 2010 12:23:58 -0400 In-Reply-To: <1283184391-7785-12-git-send-email-glommer@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: With a reliable steal time mechanism, we can tell if we're out of the cpu for very long, differentiating from the case that we simply got a real softlockup. In the case we were out of cpu, the watchdog is fed, making bogus softlockups disappear. Signed-off-by: Glauber Costa --- arch/x86/kernel/kvmclock.c | 5 +++++ 1 files changed, 5 insertions(+), 0 deletions(-) diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c index a1f4852..d217475 100644 --- a/arch/x86/kernel/kvmclock.c +++ b/arch/x86/kernel/kvmclock.c @@ -91,6 +91,7 @@ cputime_t kvm_get_steal_time(void) { u64 delta = 0; u64 *last_steal_info, this_steal_info; + int touch_wd; struct pvclock_vcpu_time_info *src; src = &get_cpu_var(hv_clock); @@ -104,6 +105,10 @@ cputime_t kvm_get_steal_time(void) delta = this_steal_info - *last_steal_info; + touch_wd = softlockup_thresh * 1000UL; + if ((touch_wd > 0) && (delta > touch_wd)) + touch_softlockup_watchdog(); + *last_steal_info = this_steal_info; put_cpu_var(steal_info); -- 1.6.2.2