The non-hierarchical cgroup v1 mode is a legacy of early days of the memory controller and doesn't bring any value today. However, it complicates the code and creates many edge cases all over the memory controller code. It's a good time to deprecate it completely. This patchset removes the internal logic, adjusts the user interface and updates the documentation. The alt patch removes some bits of the cgroup core code, which become obsolete. >From Michal Hocko: All that we know today is that we have a warning in place to complain loudly when somebody relies on use_hierarchy=0 with a deeper hierarchy. For all those years we have seen _zero_ reports that would describe a sensible usecase. Moreover we (SUSE) have backported this warning into old distribution kernels (since 3.0 based kernels) to extend the coverage and didn't hear even for users who adopt new kernels only very slowly. The only report we have seen so far was a LTP test suite which doesn't really reflect any real life usecase. v1: - added a note from Michal - added acks and reviews rfc: - https://lwn.net/Articles/835983/ Roman Gushchin (3): mm: memcg: deprecate the non-hierarchical mode docs: cgroup-v1: reflect the deprecation of the non-hierarchical mode cgroup: remove obsoleted broken_hierarchy and warned_broken_hierarchy .../admin-guide/cgroup-v1/memcg_test.rst | 8 +- .../admin-guide/cgroup-v1/memory.rst | 40 +++------ include/linux/cgroup-defs.h | 15 ---- include/linux/memcontrol.h | 7 -- kernel/cgroup/cgroup.c | 12 --- mm/memcontrol.c | 90 +++---------------- 6 files changed, 29 insertions(+), 143 deletions(-) -- 2.26.2
