[PATCH 2/2] kho: drop restriction on maximum page order

[Pratyush Yadav]

On Tue, Mar 17 2026, Mike Rapoport wrote:

> On Tue, Mar 17, 2026 at 09:12:19AM +0000, Pratyush Yadav wrote:
>> On Tue, Mar 10 2026, Mike Rapoport wrote:
>> 
>> > On Mon, Mar 09, 2026 at 12:34:07PM +0000, Pratyush Yadav wrote:
>> >> KHO currently restricts the maximum order of a restored page to the
>> >> maximum order supported by the buddy allocator. While this works fine
>> >> for much of the data passed across kexec, it is possible to have pages
>> >> larger than MAX_PAGE_ORDER.
>> >> 
>> >> For one, it is possible to get a larger order when using
>> >> kho_preserve_pages() if the number of pages is large enough, since it
>> >> tries to combine multiple aligned 0-order preservations into one higher
>> >> order preservation.
>> >> 
>> >> For another, upcoming support for hugepages can have gigantic hugepages
>> >> being preserved over KHO.
>> >> 
>> >> There is no real reason for this limit. The KHO preservation machinery
>> >> can handle any page order. Remove this artificial restriction on max
>> >> page order.
>> >> 
>> >> Signed-off-by: Pratyush Yadav <pratyush at kernel.org>
>> >> Signed-off-by: Pratyush Yadav (Google) <pratyush at kernel.org>
>> >
>> > One SOB should be enough ;-)
>> 
>> Hmm, I figured the unemployed me (who originally wrote the patch) and
>> the employed-by-google me (who is doing this new version) would count as
>> two separate entities and there should be a S-o-b for both.
>
> Maybe than something like:
>
> Signed-off-by: Pratyush Yadav (Hobbyist) <pratyush at kernel.org>
> Signed-off-by: Pratyush Yadav (Google) <pratyush at kernel.org>
>  
> ;-)
>
Yeah, that works too :-)

I'll use that when I redo some of the HugeTLB patches too

-- 
Regards,
Pratyush Yadav