On Wed, Feb 02, 2022 at 09:57:18AM +0100, Michal Hocko wrote: > On Tue 01-02-22 11:41:19, Waiman Long wrote: > > > > On 2/1/22 05:49, Michal Hocko wrote: > [...] > > > Could you be more specific? Offlined memcgs are still part of the > > > hierarchy IIRC. So it shouldn't be much more than iterating the whole > > > cgroup tree and collect interesting data about dead cgroups. > > > > What I mean is that without piggybacking on top of page_owner, we will to > > add a lot more code to collect and display those information which may have > > some overhead of its own. > > Yes, there is nothing like a free lunch. Page owner is certainly a tool > that can be used. My main concern is that this tool doesn't really > scale on large machines with a lots of memory. It will provide a very > detailed information but I am not sure this is particularly helpful to > most admins (why should people process tons of allocation backtraces in > the first place). Wouldn't it be sufficient to have per dead memcg stats > to see where the memory sits? > > Accumulated offline memcgs is something that bothers more people and I > am really wondering whether we can do more for those people to evaluate > the current state. Cgroup v2 has corresponding counters for years. Or do you mean something different?
