Messages in this thread | | | Date | Tue, 5 May 2015 15:06:03 -0400 | From | Tejun Heo <> | Subject | Re: [PATCH] sched: Relax a restriction in sched_rt_can_attach() |
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Hello, Peter.
On Tue, May 05, 2015 at 09:00:57PM +0200, Peter Zijlstra wrote: > On Tue, May 05, 2015 at 12:31:12PM -0400, Tejun Heo wrote: > > What I don't want to happen is controllers failing migrations > > willy-nilly for random reasons leaving users baffled, which we've > > actually been doing unfortunately. Maybe we need to deal with this > > fixed resource arbitration as a separate class and allow them to fail > > migration w/ -EBUSY. > > Ah, _that_ was the problem. > > Which is something created by this co-mounting of controllers.
Yeah, partly, but also that it's an extra failure mode which isn't necessary for most controllers.
> You could of course store the ss-id of the failing operation in > task_struct and have a file reporting the name of the ss-id. > > That way, there is a simple way to find out which controller failed the > migrate.
Given that the resources which can fail are very limited, I don't think we need that right now as long as we limit and document the possible failure cases clearly. Hopefully, this won't devolve into collection of arbitrary failures.
Thanks.
-- tejun
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