Re: [Xen-devel] cpupools and locking

To:	Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Subject:	Re: [Xen-devel] cpupools and locking
From:	Juergen Gross <juergen.gross@xxxxxxxxxxxxxx>
Date:	Wed, 05 May 2010 13:07:02 +0200
Cc:	George Dunlap <George.Dunlap@xxxxxxxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>
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On 05/05/2010 11:00 AM, Keir Fraser wrote:

On 05/05/2010 06:25, "Juergen Gross"<juergen.gross@xxxxxxxxxxxxxx>  wrote:

cpupool_do_domctl is called always while the domctl lock is being held. Maybe
I should have added a comment to document this assumption.


Yes please. Even better would be to explicitly add your own big lock in
cpupool.c, just for clarity. And why do you need your 'little' lock around
the lookup operations at all, in that case? It seems unnecessary if you have
a bigger lock protecting you; yet insufficient if you do not.


That's the best solution, I think. Patch attached.


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

poollock.patch
Description: Text Data

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Re: [Xen-devel] cpupools and locking