Subject: Re: linux-next: Tree for May 4 --> mm: free_area_init: allow defining max_zone_pfn in descending order does increase memory use

From: Mike Rapoport <[email-masked]>
Date: Mon, 4 May 2020 18:44:10 +0300

Ho Christian,

On Mon, May 04, 2020 at 04:50:06PM +0200, Christian Borntraeger wrote:
> Mike,
> commit 51a2f644fd020d5f090044825c388444d11029d ("mm: free_area_init: allow defining max_zone_pfn in descending order")
> does increase the memory use on s390 (e.g. 700 MB vs.1.8 GB).
> 
> Something is odd in this patch. Any idea?

Yeah, this patch is buggy. In short, it breaks zone size calculation on
s390 and some other architectures.

I've just replied at [1] with more details and a fix.

[1] https://lore.kernel.org/linux-mm/[email-masked]/

-- 
Sincerely yours,
Mike.