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