Re: [Xen-devel] Hypervisor crash(!) on xl cpupool-numa-split

To:	Stephan Diestelhorst <stephan.diestelhorst@xxxxxxx>
Subject:	Re: [Xen-devel] Hypervisor crash(!) on xl cpupool-numa-split
From:	Juergen Gross <juergen.gross@xxxxxxxxxxxxxx>
Date:	Thu, 03 Feb 2011 10:18:16 +0100
Cc:	George Dunlap <George.Dunlap@xxxxxxxxxxxxx>, "Przywara, Andre" <Andre.Przywara@xxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>, Keir Fraser <keir@xxxxxxx>, Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
Delivery-date:	Thu, 03 Feb 2011 01:19:10 -0800
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Andre, Stephan,

could you give the attached patch a try?
It moves the cpu assigning/unassigning into a tasklet always executed on the
cpu to be moved. This should avoid critical races.

Regarding Stephans rant:
You should be aware that the main critical sections are only in the tasklets.
The locking in the main routines is needed only to avoid the cpupool to be
destroyed in between.

I'm not sure whether the master_ticker patch is still needed. It seems to
break something, as my machine hung up after several 100 cpu moves (without
the new patch). I'm still investigating this problem.


Juergen

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

cpupool-idle.patch
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Re: [Xen-devel] Hypervisor crash(!) on xl cpupool-numa-split