From mboxrd@z Thu Jan 1 00:00:00 1970 From: Juergen Gross Subject: Re: Re: [Xen-users] Xen 4.1.1 crash when manipulating cpupools. Date: Mon, 14 Nov 2011 10:58:18 +0100 Message-ID: <4EC0E63A.6050707@ts.fujitsu.com> References: <553832861.1721802.1321046283027.JavaMail.root@sz0032a.westchester.pa.mail.comcast.net> <4EC0DD6A.7040007@ts.fujitsu.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============0032680925==" Return-path: In-Reply-To: <4EC0DD6A.7040007@ts.fujitsu.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: andrewpitman@comcast.net, George Dunlap Cc: xen-devel@lists.xensource.com, xen-users@lists.xensource.com List-Id: xen-devel@lists.xenproject.org This is a multi-part message in MIME format. --===============0032680925== Content-Type: multipart/alternative; boundary="------------070004070606000608050307" This is a multi-part message in MIME format. --------------070004070606000608050307 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 11/14/2011 10:20 AM, Juergen Gross wrote: > On 11/11/2011 10:18 PM, andrewpitman@comcast.net wrote: >> Juergen, >> >> It doesn't look like this has been fixed. I managed to get my 4.1.2 server >> to crash when setting the weight of Domain-0 (running in Pool-0 using >> credit2) and again when moving some cpus into a new cpupool which was set >> up to use the credit2 scheduler. > > Yeah, I could reproduce your problems on my machine. > > George, I see two problems in credit2: > > - when setting the weight of dom0, vcpu_schedule_lock_irq(current) will be > taken in sched_adjust() of schedule.c and again in csched_dom_cntl() of > sched_credit2.c resulting in a deadlock. > > - removing a cpu from a cpupool seems not to work for credit2. I removed all > but cpu 0 from Pool-0 and the dom0 vcpus were all active on cpus 1-3. It > took some time until they moved to cpu 0 (verified via 'r' hotkey on the > xen console). IMO the problem is choose_cpu() not using CSCHED_CPUONLINE(). The comment /* Leave it where it is for now. When we actually pay attention * to affinity we'll have to figure something out... */ suggests the solution isn't too easy... Juergen -- Juergen Gross Principal Developer Operating Systems PDG ES&S SWE OS6 Telephone: +49 (0) 89 3222 2967 Fujitsu Technology Solutions e-mail: juergen.gross@ts.fujitsu.com Domagkstr. 28 Internet: ts.fujitsu.com D-80807 Muenchen Company details: ts.fujitsu.com/imprint.html --------------070004070606000608050307 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 8bit On 11/14/2011 10:20 AM, Juergen Gross wrote:

On 11/11/2011 10:18 PM, andrewpitman@comcast.net wrote:

Juergen,

It doesn't look like this has been fixed. I managed to get my 4.1.2 server to crash when setting the weight of Domain-0 (running in Pool-0 using credit2) and again when moving some cpus into a new cpupool which was set up to use the credit2 scheduler.

Yeah, I could reproduce your problems on my machine. George, I see two problems in credit2: - when setting the weight of dom0, vcpu_schedule_lock_irq(current) will be taken in sched_adjust() of schedule.c and again in csched_dom_cntl() of sched_credit2.c resulting in a deadlock. - removing a cpu from a cpupool seems not to work for credit2. I removed all but cpu 0 from Pool-0 and the dom0 vcpus were all active on cpus 1-3. It took some time until they moved to cpu 0 (verified via 'r' hotkey on the xen console).

IMO the problem is choose_cpu() not using CSCHED_CPUONLINE(). The comment /* Leave it where it is for now. When we actually pay attention * to affinity we'll have to figure something out... */ suggests the solution isn't too easy... Juergen

-- 
Juergen Gross                 Principal Developer Operating Systems
PDG ES&S SWE OS6                       Telephone: +49 (0) 89 3222 2967
Fujitsu Technology Solutions              e-mail: juergen.gross@ts.fujitsu.com
Domagkstr. 28                           Internet: ts.fujitsu.com
D-80807 Muenchen                 Company details: ts.fujitsu.com/imprint.html

--------------070004070606000608050307-- --===============0032680925== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel --===============0032680925==--