From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dietmar Hahn Subject: POD: soft lockups in dom0 kernel Date: Thu, 05 Dec 2013 14:55:29 +0100 Message-ID: <1538524.5AKIkpF9LB@amur> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta3.messagelabs.com ([195.245.230.39]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1VoZOu-00015i-Ln for xen-devel@lists.xenproject.org; Thu, 05 Dec 2013 13:55:33 +0000 Received: from amur.localnet (amur.mch.fsc.net [10.172.102.13]) by sanpedro.mch.fsc.net (Postfix) with ESMTP id 9EBFC9D3980 for ; Thu, 5 Dec 2013 14:55:29 +0100 (CET) List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: xen-devel@lists.xenproject.org List-Id: xen-devel@lists.xenproject.org Hi, when creating a bigger (> 50 GB) HVM guest with maxmem > memory we get softlockups from time to time. kernel: [ 802.084335] BUG: soft lockup - CPU#1 stuck for 22s! [xend:31351] I tracked this down to the call of xc_domain_set_pod_target() and further p2m_pod_set_mem_target(). Unfortunately I can this check only with xen-4.2.2 as I don't have a machine with enough memory for current hypervisors. But it seems the code is nearly the same. My suggestion would be to do the 'pod set target' in the function xc_domain_set_pod_target() in chunks of maybe 1GB to give the dom0 scheduler a chance to run. As this is not performance critical it should not be a problem. I can reproduce this with SLES11-SP3 with Linux 3.0.101 and xen-4.2.2. # cat dummy name = "DummyOS" memory = 10000 maxmem = 12000 builder='hvm' # echo 1 > /proc/sys/kernel/watchdog_thresh # xm create -c dummy This leads to a kernel message: kernel: [ 5019.958089] BUG: soft lockup - CPU#4 stuck for 3s! [xend:20854] Any comments are welcome. Thanks. Dietmar. -- Company details: http://ts.fujitsu.com/imprint.html