Messages in this thread | | | From | Valentin Schneider <> | Subject | Re: [PATCH 1/2] sched: Fix balance_callback() | Date | Fri, 11 Sep 2020 14:27:30 +0100 |
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On 11/09/20 13:25, peterz@infradead.org wrote: > On Fri, Sep 11, 2020 at 01:17:02PM +0100, Valentin Schneider wrote: >> So that can be say __schedule() tail racing with some setprio; what's the >> worst that can (currently) happen here? Something like say two consecutive >> enqueuing of push_rt_tasks() to the callback list? > > Yeah, but that isn't in fact the case I worry most about. > > What can happen (and what I've spotted once before) is that someone > attempts to enqueue a balance_callback from a rq->lock region that > doesn't handle the calls. > > Currently that 'works', that is, it will get ran _eventually_. But > ideally we'd want that to not work and issue a WARN. We want the > callbacks to be timely. > > So basically all of these machinations we in order to add the WARN :-)
Makes sense, thanks!
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