The discussions on the patch series [1] to add memory.reclaim has shown that it is desirable to add an argument to control the type of memory being reclaimed by invoked proactive reclaim using memory.reclaim. I am proposing adding a swappiness optional argument to the interface. If set, it overwrites vm.swappiness and per-memcg swappiness. This provides a way to enforce user policy on a stateless per-reclaim basis. We can make policy decisions to perform reclaim differently for tasks of different app classes based on their individual QoS needs. It also helps for use cases when particularly page cache is high and we want to mainly hit that without swapping out. The interface would be something like this (utilizing the nested-keyed interface we documented earlier): $ echo "200M swappiness=30" > memory.reclaim Looking forward to hearing thoughts about this before I go ahead and send a patch. [1]https://lore.kernel.org/lkml/20220331084151.2600229-1-yosryahmed@xxxxxxxxxx/
