| 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. |
