[libvirt] [Xen-devel] [PATCH 0/3] libxl: domain destroy fixes

Jim Fehlig jfehlig at suse.com
Fri Mar 27 18:34:04 UTC 2015


Konrad Rzeszutek Wilk wrote:
> On Wed, Mar 25, 2015 at 02:08:33PM -0600, Jim Fehlig wrote:
>   
>> This small series of patches fixes some issues wrt domain destroy in
>> the libxl driver.  The primary motivation for this work is to
>> prevent locking the virDomainObj during long running destroy operations
>> on large memory domains.
>>
>> Patch 1 moves job acquisition from libxlDomainStart to it's callers so
>> they have more control over when the job is acquired.  Patch 2 fixes a
>> few spots where we never acquired a job during domain destroy.  Patch 3
>> contains the interesting change, where the virDomainObj is unlocked
>> during the long-running destroy operation.
>>
>> This series wraps up my work to improve parallel OpenStack Tempest runs
>> against the libxl driver.  With libvirt.git master + this series + a
>> patched libxl [1], I've successfully run a reproducer that was hitting
>> the same issues encountered by Tempest.
>>
>> [1] libxl commits from xen.git: 93699882d, f1335f0d, 4783c99a, 1c91d6fba,
>> and 188e9c54.  I'll contact the stable branch maintainers and ask them
>> to include these commits in the next Xen 4.4.x and 4.5.x releases.
>>
>> Jim Fehlig (3):
>>   libxl: Move job acquisition in libxlDomainStart to callers
>>   libxl: acquire a job when destroying a domain
>>   libxl: drop virDomainObj lock when destroying a domain
>>     
>
> I am no expert at this- but I dug through the code to understand how
> the job and locking is done and now I am more comfortable with it.
>
> Since I am new to this I went through all of the the callsites (which used
> the job now) from the driver to make sure that there are no chained calls
> (one function calling another which also uses a mutex or job locking).
>
> I only found one culprit (libxlDomainAutoCoreDump being called from
>  libxlDomainShutdownThread).
>
> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk at oracle.com>
>   

Thanks for taking time to review the series and familiarize yourself
with the libvirt libxl code!  As mentioned, I squashed in your
libxlDomainAutoCoreDump fix in 2/3.

Do any other libvirt devs have time for a quick review?  I'd like to
push this series, and the dom0 ballooning fix, for 1.2.14 if there are
no objections.  The latter was reviewed by Stefano Stabellini before the
freeze

https://www.redhat.com/archives/libvir-list/2015-March/msg01248.html

Regards,
Jim




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