I've been experimenting with these changes to allow for separate updating/flushing of cgroup stats per-subsystem. The idea was instead of having a single per-cpu rstat tree for managing stats across all subsystems, we could maybe split up the rstat trees into separate trees for each subsystem. So each cpu would have individual trees for each subsystem. It would allow subsystems to update and flush their stats without having any contention with others, i.e. the io subsystem would not have to wait for an in progress memory subsystem flush to finish. The core change is moving the rstat entities off of the cgroup struct and onto the cgroup_subsystem_state struct. Every patch revolves around that concept. I reached a point where this started to feel stable in my local testing, so I wanted to share and get feedback on this approach. JP Kobryn (8): change cgroup to css in rstat updated and flush api change cgroup to css in rstat internal flush and lock funcs change cgroup to css in rstat init and exit api split rstat from cgroup into separate css separate locking between base css and others isolate base stat flush remove unneeded rcu list remove bpf rstat flush from css generic flush block/blk-cgroup.c | 4 +- include/linux/cgroup-defs.h | 35 ++--- include/linux/cgroup.h | 8 +- kernel/cgroup/cgroup-internal.h | 4 +- kernel/cgroup/cgroup.c | 79 ++++++----- kernel/cgroup/rstat.c | 225 +++++++++++++++++++------------- mm/memcontrol.c | 4 +- 7 files changed, 203 insertions(+), 156 deletions(-) -- 2.47.1
