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Date:   Thu, 13 Oct 2022 13:44:29 +0200
From:   Michal Hocko <mhocko@suse.com>
To:     Doug Berger <opendmb@gmail.com>
Cc:     David Hildenbrand <david@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Jonathan Corbet <corbet@lwn.net>,
        Mike Rapoport <rppt@kernel.org>, Borislav Petkov <bp@suse.de>,
        "Paul E. McKenney" <paulmck@kernel.org>,
        Neeraj Upadhyay <quic_neeraju@quicinc.com>,
        Randy Dunlap <rdunlap@infradead.org>,
        Damien Le Moal <damien.lemoal@opensource.wdc.com>,
        Muchun Song <songmuchun@bytedance.com>,
        KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
        Mel Gorman <mgorman@suse.de>,
        Mike Kravetz <mike.kravetz@oracle.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Oscar Salvador <osalvador@suse.de>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org
Subject: Re: [PATCH v2 2/9] mm/vmstat: show start_pfn when zone spans pages
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On Wed 12-10-22 16:57:53, Doug Berger wrote:
[...]
> I was working from the notion that the classic 'movablecore' implementation
> keeps the ZONE_MOVABLE zone the last zone on System RAM so it always spans
> the last page on the node (i.e. 0x33ffff000). My implementation moves the
> start of ZONE_MOVABLE up to the lowest page of any defined DMBs on the node.

I wouldn't rely on movablecore specific implementation. ZONE_MOVABLE can
span any physical address range. ZONE_NORMAL usually covers any ranges
not covered by more specific zones like ZONE_DMA{32}. At least on most
architectures I am familiar with.
-- 
Michal Hocko
SUSE Labs