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Date:   Fri, 19 Apr 2019 07:05:21 -0700
From:   Matthew Wilcox <willy@infradead.org>
To:     Mel Gorman <mgorman@techsingularity.net>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Mikulas Patocka <mpatocka@redhat.com>,
        James Bottomley <James.Bottomley@hansenpartnership.com>,
        linux-parisc@vger.kernel.org, linux-mm@kvack.org,
        Vlastimil Babka <vbabka@suse.cz>,
        LKML <linux-kernel@vger.kernel.org>, linux-arch@vger.kernel.org
Subject: DISCONTIGMEM is deprecated
Message-ID: <20190419140521.GI7751@bombadil.infradead.org>
References: <20190419094335.GJ18914@techsingularity.net>
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On Fri, Apr 19, 2019 at 10:43:35AM +0100, Mel Gorman wrote:
> DISCONTIG is essentially deprecated and even parisc plans to move to
> SPARSEMEM so there is no need to be fancy, this patch simply disables
> watermark boosting by default on DISCONTIGMEM.

I don't think parisc is the only arch which uses DISCONTIGMEM for !NUMA
scenarios.  Grepping the arch/ directories shows:

alpha (does support NUMA, but also non-NUMA DISCONTIGMEM)
arc (for supporting more than 1GB of memory)
ia64 (looks complicated ...)
m68k (for multiple chunks of memory)
mips (does support NUMA but also non-NUMA)
parisc (both NUMA and non-NUMA)

I'm not sure that these architecture maintainers even know that DISCONTIGMEM
is deprecated.  Adding linux-arch to the cc.