CA-286165: Only non-VF PCI need to update dependencies

[xiewei20082008]

Signed-off-by: Wei Xie wei.xie@citrix.com

[xiewei20082008]

Just Having test on this method. Also works.

[robhoes]

This may work, but it does a get_phyfn_path twice for every PCI, which is a filesystem operation: once in update_pf_vf_relations and once in update_dependencies.

[coveralls]

Coverage increased (+0.003%) to 20.353% when pulling bcc538b on xiewei20082008:private/weix/CA-286165-update-dependencies into 095a1f8 on xapi-project:master.

[xiewei20082008]

Hi @robhoes Performance impact solved. Changed a bit of structure of the code. I think it is worth refining it since actually we improved the performance eventually - the update_dependencies is O(n^2) and after the change we just need to do update_dependencies for non-VF only, thinking about in the future we could have a MxVGPU with hundreds of VFs other than current 16 VFs. That is a lot of time. :)