On Wed 08-11-23 14:58:11, Huan Yang wrote: > In some cases, we need to selectively reclaim file pages or anonymous > pages in an unbalanced manner. > > For example, when an application is pushed to the background and frozen, > it may not be opened for a long time, and we can safely reclaim the > application's anonymous pages, but we do not want to touch the file pages. Could you explain why? And also why do you need to swap out in that case? > This patchset extends the proactive reclaim interface to achieve > unbalanced reclamation. Users can control the reclamation tendency by > inputting swappiness under the original interface. Specifically, users > can input special values to extremely reclaim specific pages. Other have already touched on this in other replies but v2 doesn't have a per-memcg swappiness > Example: > echo "1G" 200 > memory.reclaim (only reclaim anon) > echo "1G" 0 > memory.reclaim (only reclaim file) > echo "1G" 1 > memory.reclaim (only reclaim file) > > Note that when performing unbalanced reclamation, the cgroup swappiness > will be temporarily adjusted dynamically to the input value. Therefore, > if the cgroup swappiness is further modified during runtime, there may > be some errors. In general this is a bad semantic. The operation shouldn't have side effect that are potentially visible for another operation. -- Michal Hocko SUSE Labs
