* Lukas Straub (lukasstra...@web.de) wrote: > Terminology: > instance = one (nbd) blockdev/one chardev/the single migrationstate > connection = one TCP connection > > Hello Everyone, > Having read all the comments, here is proposal v2: > Every instance registers itself with a unique name in the form > "blockdev:<node-name>", "chardev:<chardev-name>" and "migration" using > yank_register_instance which will do some sanity checks like checking if the > same name exists already. Then (multiple) yank functions can be registered as > needed with that single name. When the instance exits/is removed, it > unregisters all yank functions and unregisters it's name with > yank_unregister_instance which will check if all yank functions where > unregistered. > Every instance that supports the yank feature will register itself and the > yank functions unconditionally (No extra 'yank' option per instance). > The 'query-yank' oob qmp command lists the names of all registered instances. > The 'yank' oob qmp command takes a list of names and for every name calls all > yank functions registered with that name. Before doing anything, it will > check that all names exist. > > If the instance has multiple connections (say, migration with multifd), i > don't think it makes much sense to just shutdown one connection. Calling > 'yank' on a instance will always shutdown all connections of that instance.
Agreed. > Yank functions are generic and in no way limited to connections. Say, if > migration is started to an 'exec:' address, migration could register a yank > function to kill that external command on yank (Won't be implemented yet > though). One thing we need to be care of is that the yank functions stay suitable for OOB calling. Dave > Regards, > Lukas Straub -- Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
