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+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.