Re: DISCONTIGMEM is deprecated

Matthew Wilcox
2019-04-21T13:26:13Z

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 ;-)