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.