Re: [Xen-devel] [PATCH v3 4/6] xen: don't free percpu areas during suspend

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 02.04.19 at 07:34, <jgross@xxxxxxxx> wrote:
> Instead of freeing percpu areas during suspend and allocating them
> again when resuming keep them. Only free an area in case a cpu didn't
> come up again when resuming.
> 
> It should be noted that there is a potential change in behaviour as
> the percpu areas are no longer zeroed out during suspend/resume. While
> I have checked the called cpu notifier hooks to cope with that there
> might be some well hidden dependency on the previous behaviour. OTOH
> a component not registering itself for cpu down/up and expecting to
> see a zeroed percpu variable after suspend/resume is kind of broken
> already. And the opposite case, where a component is not registered
> to be called for cpu down/up and is not expecting a percpu variable
> suddenly to be zero due to suspend/resume is much more probable,
> especially as the suspend/resume functionality seems not to be tested
> that often.
> 
> Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
> Reviewed-by: Dario Faggioli <dfaggioli@xxxxxxxx>

Acked-by: Jan Beulich <jbeulich@xxxxxxxx>

Wasn't there a request though to do the same on Arm? Even if
right now Arm doesn't support suspend/resume out of the box,
I think it would be better if such relatively generic adjustments
were done in lock step.

Jan



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