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

[Mike Rapoport <rppt@kernel.org>]

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@kernel.org>
> >> Signed-off-by: Pratyush Yadav (Google) <pratyush@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@kernel.org>
Signed-off-by: Pratyush Yadav (Google) <pratyush@kernel.org>
 
;-)

> Anyway, I am fine with dropping either one of the two.
> 
> >
> > Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
> 
> Thanks!
> 
> [...]
> 
> -- 
> Regards,
> Pratyush Yadav

-- 
Sincerely yours,
Mike.