On Thu, Jan 10, 2019 at 03:14:40AM +0800, Yang Shi wrote: > > We have some usecases which create and remove memcgs very frequently, > and the tasks in the memcg may just access the files which are unlikely > accessed by anyone else. So, we prefer force_empty the memcg before > rmdir'ing it to reclaim the page cache so that they don't get > accumulated to incur unnecessary memory pressure. Since the memory > pressure may incur direct reclaim to harm some latency sensitive > applications. We have kswapd for exactly this purpose. Can you lay out more details on why that is not good enough, especially in conjunction with tuning the watermark_scale_factor etc.? We've been pretty adamant that users shouldn't use drop_caches for performance for example, and that the need to do this usually is indicative of a problem or suboptimal tuning in the VM subsystem. How is this different?
