Re: [Xenomai-core] xnshadow_relax in taskexit_event

[Jan Kiszka <jan.kiszka@domain.hid>]

Philippe Gerum wrote:
> Jan Kiszka wrote:
>> Philippe Gerum wrote:
>>> Jan Kiszka wrote:
>>>> Hi,
>>>>
>>>> this looks suspicious to me:
>>>>
>>>> static inline void do_taskexit_event(struct task_struct *p)
>>>> {
>>>>     ...
>>>>     if (xnpod_shadow_p())
>>>>         xnshadow_relax(0);
>>>>
>>>> A) The only call context of this hook is do_exit() - and that's Linux
>>>> kernel code which should always run in secondary mode, no?
>>>>
>>> It is a left-over from the days when do_exit() could be called from
>>> primary context directly on behalf on the shadow unmapping code; now
>>> we go through an APC, so that should be ok.
>>
>> Mmm, then I wonder if we shouldn't be able to drop the explicit
>> xnpod_schedule() from do_taskexit_event() as well: we always enter this
>> code over the ROOT thread, and xnpod_delete_thread() will only kill a
>> suspended thread. So there should be no need to reschedule afterwards.
>> Will post an updated patch.
>>
> 
> Nak, the deletion hook may alter the scheduling state.

OK. Is such a hook expected to call xnsched_set_resched in that case,
ie. can we drop it?

Jan

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