Messages in this thread | | | Date | Thu, 12 Feb 2015 07:01:21 -0600 | From | Josh Poimboeuf <> | Subject | Re: [RFC PATCH 6/9] livepatch: create per-task consistency model |
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On Thu, Feb 12, 2015 at 01:42:01PM +0100, Jiri Kosina wrote: > On Thu, 12 Feb 2015, Peter Zijlstra wrote: > > > > Well, the fact indisputable fact is that there is a demand for this. It's > > > not about one machine, it's about scheduling dowtimes of datacentres. > > > > The changelog says: > > > > > ... A patch can remain in the > > > transition state indefinitely, if any of the tasks are stuck in the > > > previous universe. > > > > Therefore there is no scheduling anything. Without timeliness guarantees > > you can't make a schedule. > > > > Might as well just reboot, at least that's fairly well guaranteed to > > happen. > > All running (reasonably alive) tasks will be running patched code though. > > You can't just claim complete victory (and get ready for accepting another > patch, etc) if there is a long-time sleeper that hasn't been converted > yet.
Agreed. And also we have several strategies for reducing the time needed to get all tasks to a patched state (see patch 9 of this series for more details). The goal is to not leave systems in limbo for more than a few seconds.
-- Josh
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