Messages in this thread | | | Date | Tue, 10 Mar 2015 16:28:26 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH 2/3] locking: ww_mutex: Allow to use rt_mutex instead of mutex for the baselock |
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On Tue, Mar 10, 2015 at 03:10:46PM +0100, Maarten Lankhorst wrote: > Op 10-03-15 om 13:37 schreef Peter Zijlstra:
> > So IIRC this is the function that checks who gets wounded (and gets to > > do the whole retry thing), right? > > > > So for the RT case, I think we should extend it to not (primarily) be a > > FIFO thing, but also consider the priority of the tasks involved. > > > > Maybe a little something like: > > > > if (hold_ctx->task->prio < ctx->task->prio) > > return -EDEADLOCK; > > > > before the timestamp check; although I suppose we should also add a > > deadline test in case both prios are -1.
> I think that's useful but if you implement -EDEADLK based on thread > priority, any boosted thread should receive -EDEADLK when it tries to > acquire a new lock in the same context, to force it to back off..
But _only_ if the boost comes from inside the ww_ctx, right?
Yeah, implementing that might be tricky, maybe we can keep it as a note for now ;)
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