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) > > I'm not sure that these architecture maintainers even know that DISCONTIGMEM > is deprecated. Adding linux-arch to the cc. Poor wording then -- yes, DISCONTIGMEM is still used but look where it's used. I find it impossible to believe that any new arch would support DISCONTIGMEM or that DISCONTIGMEM would be selected when SPARSEMEM is available.`It's even more insane when you consider that SPARSEMEM can be extended to support VMEMMAP so that it has similar overhead to FLATMEM when mapping pfns to struct pages and vice-versa. -- Mel Gorman SUSE Labs
