On Mon, Aug 13, 2018 at 06:48:42AM -0700, Tejun Heo wrote: > Hello, Konstantin. > > On Mon, Aug 13, 2018 at 09:58:05AM +0300, Konstantin Khlebnikov wrote: > > After removing cgroup subsystem state could leak or live in background > > forever because it is pinned by some reference. For example memory cgroup > > could be pinned by pages in cache or tmpfs. > > > > This patch adds common debugfs interface for listing basic state for each > > controller. Controller could define callback for dumping own attributes. > > > > In file /sys/kernel/debug/cgroup/<controller> each line shows state in > > format: <common_attr>=<value>... [-- <controller_attr>=<value>... ] > > Seems pretty useful to me. Roman, Johannes, what do you guys think? Generally I like the idea of having more introspection into offlined cgroups, but I wonder if having only memory= and swap= could be a little too terse to track down what exactly is pinning the groups. Roman has more experience debugging these pileups, but it seems to me that unless we add a breakdown off memory, and maybe make slabinfo available for these groups, that in practice this might not provide that much more insight than per-cgroup stat counters of dead children.
