Re: Kconfig doesn't support select on choices (was Re: [GIT PULL]nohz: Adaptively stop the tick, finally)
From: Frederic Weisbecker
Date: Thu Apr 25 2013 - 09:47:21 EST
2013/4/25 Ingo Molnar <mingo@xxxxxxxxxx>:
> * Frederic Weisbecker <fweisbec@xxxxxxxxx> wrote:
>> 2013/4/25 Ingo Molnar <mingo@xxxxxxxxxx>:
>> > * Frederic Weisbecker <fweisbec@xxxxxxxxx> wrote:
>> >> > depends on VIRT_CPU_ACCOUNTING_GEN
>> >> >
>> >> > It should _really_ select both the RCU and the CPU time accounting model
>> >> > automatically!
>> >> Yeah I know. I have yet to fix that in Kconfig (it's a Kconfig limitation).
>> > Why cannot we simply select it and its dependencies, explicitly, for the
>> > time being? Something like:
>> > depends on 64BIT
>> > select VIRT_CPU_ACCOUNTING
>> > select VIRT_CPU_ACCOUNTING_GEN
>> > 90% of the .config's have VIRT_CPU_ACCOUNTING_GEN turned off, because it's
>> > a default-off feature - so dynticks-full is effectively hidden from the
>> > large majority of testers...
>> Whatever we do, it seems that select does not work with choices.
>> Michal, we are running into an issue where a Kconfig option needs to
>> select CONFIG_VIRT_CPU_ACCOUNTING_GEN but this latter option is part of
>> a choice menu so it doesn't work. As a result we are forced to use a
>> "depends on" and this hides the high level option we are interested in
>> (here full dynticks) behind its low level dependency. How hard do you
>> think it would be to fix this? I tried something that worked half-way
>> but I quickly got lost in the Kconfig maze.
> While it's not an ideal solution, we could try to create three bools out
> of the choice options, as a workaround?
I thought about that yeah, at least for a temporary solution. Let's
try it, I'll see what I can get.
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