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
