Re: [PATCH 4/4] mm: introduce per-node proactive reclaim interface

[Hillf Danton]

Davidlohr Bueso <dave@xxxxxxxxxxxx> writes:

> This adds support for allowing proactive reclaim in general on a
> NUMA system. A per-node interface extends support for beyond a
> memcg-specific interface, respecting the current semantics of
> memory.reclaim: respecting aging LRU and not supporting
> artificially triggering eviction on nodes belonging to non-bottom
> tiers.
>
> This patch allows userspace to do:
>
>      echo "512M swappiness=10" > /sys/devices/system/node/nodeX/reclaim
>
When kswapd is active, this is not needed.
When kswapd is idle, why is this needed?