[PATCH v7 16/22] sched: Defer wakeup in ttwu() for unschedulable frozen tasks

Peter Zijlstra peterz at infradead.org
Thu May 27 07:55:32 PDT 2021


On Thu, May 27, 2021 at 03:44:12PM +0100, Will Deacon wrote:
> I'm not seeing how this handles tasks which weren't put in the freezer
> because they have PF_FREEZER_SKIP set. For these tasks, we need to make
> sure that they don't become runnable before we have onlined a core which
> is capable of running them, and this could occur because of any old
> wakeup (i.e. whatever it was that they blocked on).

I was under the impression that userspace tasks could not have
PF_FREEZER_SKIP set.. let me look harder.



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