Messages in this thread | | | Date | Wed, 10 Apr 2024 14:51:26 +0200 | From | Sebastian Andrzej Siewior <> | Subject | Re: [PATCH v3 3/4] perf: Remove perf_swevent_get_recursion_context() from perf_pending_task(). |
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On 2024-04-10 12:38:50 [+0200], Frederic Weisbecker wrote: > > Anyway, I misunderstood the concept > > before. That means we need to keep that counter here and a > > migrate_disable() is needed to avoid CPU migration which is sad. > > I fear that won't work either. The task is then pinned but another > task can come up on that CPU and its software events will be ignored...
oh, right.
> Some alternatives: > > _ Clear event->pending_work = 0 after perf_sigtrap(), preventing an > event in there from adding a new task work. We may miss a signal though... > > _ Make the recursion context per task on -RT...
The per-task counter would be indeed the easiest thing to do. But then only for task context, right?
But why would we miss a signal if we clean event->pending_work late? Isn't cleaning late same as clearing in perf_swevent_put_recursion_context()? If clearing pending_work late works, I would prefer to avoid yet another per-task counter if possible.
> > > Thanks.
Sebastian
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