[ovirt-devel] contEIOVMs regression?

Hi list, I am taking a look at Bug 1157421 [1] which describes a situation where VM's that are paused with an -EIO error are not automatically resumed after the problem with storage has been corrected. I have some patches [2] on gerrit that resolve the problem. Since this appears to be a regression I am looking at a non-intrusive way to fix it in the 3.5 branch. There is some disagreement on the proper way to fix this so I am hoping we can arrive at a solution through an open discussion. The main issue at hand is with the Event/Callback mechanism we use to call clientIF.contEIOVMs. According to my experiments and this online discussion [3] weakref does not work for instance methods such as clientIF.contEIOVMs. Our Event class uses weakref to prevent it from holding references to registered callback functions. I see two easy ways to fix the regression: 1) Treat clientIF as a singleton class (which it is) and make contEIOVMs a module-level method which gets the clientIF instance and calls it's bound contEIOVMs method. See my patches [2] for the code behind this idea. 2) Allow Event to maintain a strong reference on the bound clientIF.contEIOVMs method. This will allow the current code to work as designed but will change the Event implementation to accomodate this specific use case. Since no one else appears to be using this code, it should have no functional impact. Are there any other ideas I'm missing? I am aware of plans to refactor this code for 3.6 but I am more interested in a short-term, practical solution to address the current regression. Thanks for offering your insight on this problem. [1] https://bugzilla.redhat.com/show_bug.cgi?id=1157421 [2] http://gerrit.ovirt.org/#/q/status:open+project:vdsm+branch:master+topic:... -- Adam Litke