From: Mel Gorman <mgorman@techsingularity.net>
To: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport <rppt@linux.ibm.com>,
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: Re: DISCONTIGMEM is deprecated
Date: Sun, 21 Apr 2019 22:16:04 +0100 [thread overview]
Message-ID: <20190421211604.GN18914@techsingularity.net> (raw)
In-Reply-To: <20190421132606.GJ7751@bombadil.infradead.org>
On Sun, Apr 21, 2019 at 06:26:07AM -0700, Matthew Wilcox wrote:
> On Sun, Apr 21, 2019 at 09:38:59AM +0300, Mike Rapoport wrote:
> > On Fri, Apr 19, 2019 at 07:05:21AM -0700, Matthew Wilcox wrote:
> > > 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)
> >
> > i386 NUMA as well
>
> I clearly over-trimmed. The original assumption that Mel had was that
> DISCONTIGMEM => NUMA, and that's not true on the above six architectures.
> It is true on i386 ;-)
32-bit NUMA systems should be non-existent in practice. The last NUMA
system I'm aware of that was both NUMA and 32-bit only died somewhere
between 2004 and 2007. If someone is running a 64-bit capable system in
32-bit mode with NUMA, they really are just punishing themselves for fun.
--
Mel Gorman
SUSE Labs
next prev parent reply other threads:[~2019-04-21 21:16 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-19 9:43 [PATCH] mm: Do not boost watermarks to avoid fragmentation for the DISCONTIG memory model Mel Gorman
2019-04-19 14:05 ` DISCONTIGMEM is deprecated Matthew Wilcox
2019-04-19 14:28 ` Mel Gorman
2019-04-19 20:08 ` Helge Deller
2019-05-05 8:53 ` Mike Rapoport
2019-04-21 6:38 ` Mike Rapoport
2019-04-21 13:26 ` Matthew Wilcox
2019-04-21 21:16 ` Mel Gorman [this message]
2019-04-23 7:13 ` Christoph Hellwig
2019-04-24 11:33 ` Mike Rapoport
2019-04-24 12:21 ` Mel Gorman
2019-04-28 8:11 ` Christoph Hellwig
2019-05-01 20:46 ` Mike Rapoport
2019-04-22 17:29 ` Christopher Lameter
2019-04-23 16:49 ` Meelis Roos
2019-04-28 8:13 ` Christoph Hellwig
2019-04-29 16:58 ` Luck, Tony
2019-04-29 20:09 ` Christoph Hellwig
2019-04-30 13:40 ` Christopher Lameter
2019-04-23 6:33 ` [PATCH] mm: Do not boost watermarks to avoid fragmentation for the DISCONTIG memory model Vlastimil Babka
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