Hi Hannes, On Thu, Jun 16, 2016 at 10:41:02AM -0400, Johannes Weiner wrote: > On Wed, Jun 15, 2016 at 09:40:27AM +0900, Minchan Kim wrote: > > A question is it seems cgroup2 doesn't have per-cgroup swappiness. > > Why? > > > > I think we need it in one-cgroup-per-app model. > > Can you explain why you think that? > > As we have talked about this recently in the LRU balancing thread, > swappiness is the cost factor between file IO and swapping, so the > only situation I can imagine you'd need a memcg swappiness setting is > when you have different cgroups use different storage devices that do > not have comparable speeds. > > So I'm not sure I understand the relationship to an app-group model. Sorry for lacking the inforamtion. I should have written more clear. In fact, what we need is *per-memcg-swap-device*. What I want is to avoid kill background application although memory is overflow because cold launcing of app takes a very long time compared to resume(ie, just switching). I also want to keep a mount of free pages in the memory so that new application startup cannot be stuck by reclaim activities. To get free memory, I want to reclaim less important app rather than killing. In this time, we can support two swap devices. A one is zram, other is slow storage but much bigger than zram size. Then, we can use storage swap to reclaim pages for not-important app while we can use zram swap for for important app(e.g., forground app, system services, daemon and so on). IOW, we want to support mutiple swap device with one-cgroup-per-app and the storage speed is totally different. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>