Messages in this thread | | | Date | Tue, 24 Oct 2017 11:40:40 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH 0/6] Boot-time switching between 4- and 5-level paging for 4.15, Part 1 |
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* Kirill A. Shutemov <kirill@shutemov.name> wrote:
> On Mon, Oct 23, 2017 at 02:40:14PM +0200, Ingo Molnar wrote: > > > > * Kirill A. Shutemov <kirill@shutemov.name> wrote: > > > > > > Making a variable that 'looks' like a constant macro dynamic in a rare Kconfig > > > > scenario is asking for trouble. > > > > > > We expect boot-time page mode switching to be enabled in kernel of next > > > generation enterprise distros. It shoudn't be that rare. > > > > My point remains even with not-so-rare Kconfig dependency. > > I don't follow how introducing new variable that depends on Kconfig option > would help with the situation.
A new, properly named variable or function (max_physmem_bits or max_physmem_bits()) that is not all uppercase would make it abundantly clear that it is not a constant but a runtime value.
> We would end up with inverse situation: people would use MAX_PHYSMEM_BITS > where the new variable need to be used and we will in the same situation.
It should result in sub-optimal resource allocations worst-case, right?
We could also rename it to MAX_POSSIBLE_PHYSMEM_BITS to make it clear that the real number of bits can be lower.
Thanks,
Ingo
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