linux-kernel - Re: [PATCH v1 2/4] mm/memory_hotplug: Handle unaligned start and nr_pages in online_pages

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Message-ID: <710da2da-6ad5-33f1-ff6e-88ed7c91607b@redhat.com>
Date:   Sat, 10 Aug 2019 11:18:42 +0200
From:   David Hildenbrand <david@...hat.com>
To:     Andrew Morton <akpm@...ux-foundation.org>
Cc:     linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        Arun KS <arunks@...eaurora.org>,
        Oscar Salvador <osalvador@...e.de>,
        Michal Hocko <mhocko@...e.com>,
        Pavel Tatashin <pasha.tatashin@...een.com>,
        Dan Williams <dan.j.williams@...el.com>,
        Sasha Levin <sashal@...nel.org>
Subject: Re: [PATCH v1 2/4] mm/memory_hotplug: Handle unaligned start and
 nr_pages in online_pages_blocks()

On 09.08.19 23:46, Andrew Morton wrote:
> On Fri,  9 Aug 2019 14:56:59 +0200 David Hildenbrand <david@...hat.com> wrote:
> 
>> Take care of nr_pages not being a power of two and start not being
>> properly aligned. Essentially, what walk_system_ram_range() could provide
>> to us. get_order() will round-up in case it's not a power of two.
>>
>> This should only apply to memory blocks that contain strange memory
>> resources (especially with holes), not to ordinary DIMMs.
> 
> I'm assuming this doesn't fix any known runtime problem and that a
> -stable backport isn't needed.

Yeah, my understanding is that this would only apply when offlining and
re-onlining boot memory that contains such weird memory holes. I don't
think this is stable material.

Thanks!

> 
>> Fixes: a9cd410a3d29 ("mm/page_alloc.c: memory hotplug: free pages as higher order")
> 
> To that end, I replaced this with my new "Fixes-no-stable" in order to
> discourage -stable maintainers from overriding our decision.
> 
>> Cc: Arun KS <arunks@...eaurora.org>
>> Cc: Andrew Morton <akpm@...ux-foundation.org>
>> Cc: Oscar Salvador <osalvador@...e.de>
>> Cc: Michal Hocko <mhocko@...e.com>
>> Cc: Pavel Tatashin <pasha.tatashin@...een.com>
>> Cc: Dan Williams <dan.j.williams@...el.com>
>> Signed-off-by: David Hildenbrand <david@...hat.com>


-- 

Thanks,

David / dhildenb