2020-05-04 15:46:50

by Mike Rapoport

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

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 protected]/

--
Sincerely yours,
Mike.


2020-05-04 21:12:35

by Stephen Rothwell

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

Hi Mike,

On Mon, 4 May 2020 18:44:10 +0300 Mike Rapoport <[email protected]> wrote:
>
> 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 protected]/

I have added that to linux-next for today.

--
Cheers,
Stephen Rothwell

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2020-05-05 09:38:27

by Christian Borntraeger

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



On 04.05.20 23:08, Stephen Rothwell wrote:
> Hi Mike,
>
> On Mon, 4 May 2020 18:44:10 +0300 Mike Rapoport <[email protected]> wrote:
>>
>> 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 protected]/
>
> I have added that to linux-next for today.
>

Ack, 5.7.0-rc4-next-20200505 seems to work fine.