Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756340Ab2BQB5q (ORCPT ); Thu, 16 Feb 2012 20:57:46 -0500 Received: from oz.csail.mit.edu ([128.30.30.239]:47189 "EHLO mail.mgebm.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753865Ab2BQB5o (ORCPT ); Thu, 16 Feb 2012 20:57:44 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Date: Thu, 16 Feb 2012 20:57:40 -0500 From: Eric B Munson To: john stultz Cc: Dave Jones , Linux Kernel Subject: Re: soft lockup detector & virtualisation In-Reply-To: References: <20120216231533.GA7392@redhat.com> Message-ID: <78aa6599cf8dddc4d44f39bcdd0bb917@mgebm.net> User-Agent: Roundcube Webmail/0.5.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1428 Lines: 37 On Thu, 16 Feb 2012 17:39:38 -0800, john stultz wrote: > On Thu, Feb 16, 2012 at 3:15 PM, Dave Jones wrote: >> Lately I've noticed quite a few soft lockup bugs being reported. >> In many of them, they're coming from inside virtual guests. >> >> Is the softlockup detector fundamentally broken in this situation ? >> >> If the host doesn't schedule the guest for whatever reason, >> or the user suspends the VM and resumes it later ? >> >> Here's the most recent example: >> https://bugzilla.redhat.com/attachment.cgi?id=563767 >> >> In many of these, the code where it's "stuck" isn't anything >> special, which is why I think the guest just hasn't had a >> timeslice in 185 seconds. >> >> Is there some way we can perhaps detect we're running virtualised, >> and disable the detector automatically ? > > I think Eric's work (See "Add check for suspended vm in softlockup > detector" sent out today) tries to address this issue. > > thanks > -john The work I have been doing specifically handles the case where the hypervisor suspends the guest. There is talk of extending that work to handle preemption as well, which I think will cover your use case. Eric -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/