1What: /sys/kernel/mm/numa/ 2Date: June 2021 3Contact: Linux memory management mailing list <linux-mm@kvack.org> 4Description: Interface for NUMA 5 6What: /sys/kernel/mm/numa/demotion_enabled 7Date: June 2021 8Contact: Linux memory management mailing list <linux-mm@kvack.org> 9Description: Enable/disable demoting pages during reclaim 10 11 Page migration during reclaim is intended for systems 12 with tiered memory configurations. These systems have 13 multiple types of memory with varied performance 14 characteristics instead of plain NUMA systems where 15 the same kind of memory is found at varied distances. 16 Allowing page migration during reclaim enables these 17 systems to migrate pages from fast tiers to slow tiers 18 when the fast tier is under pressure. This migration 19 is performed before swap. It may move data to a NUMA 20 node that does not fall into the cpuset of the 21 allocating process which might be construed to violate 22 the guarantees of cpusets. This should not be enabled 23 on systems which need strict cpuset location 24 guarantees. 25