On 2013/4/13 7:10, Tejun Heo wrote: > It's a sad fact that at this point various cgroup controllers are > carrying so many idiosyncrasies and pure insanities that it simply > isn't possible to reach any sort of sane consistent behavior while > staying compatible with what already has been exposed to userland. > > To make progress, those behaviors need to go but we can't simply drop > or change the crazies as those are directly visible to userland. This > patchset implements a mount option - sane_behavior - which turns on > new saner behaviors, so that we can keep providing the old behaviors > while and after transitioning to saner ones. > > As the behaviors which should be changed are still being determined > and then implemented, __DEVEL__ prefix is added to the mount option > and it triggers a warning message when used. > > The mount option changes the following behaviors after this patchset. > > * Mount options "noprefix" and "clone_children" are disallowed. Also, > cgroupfs file cgroup.clone_children is not created. > > * When mounting an existing superblock, mount options should match. > This is currently pretty crazy. If one mounts a cgroup, creates a > subdirectory, unmounts it and then mount it again with different > option, it looks like the new options are applied but they aren't. > > * Remount is disallowed. > > * memcg: .use_hierarchy is forced on and the cgroupfs file is not > created. > > and there are a lot more to come. Basically, when turned on, all > controllers should be ready to be mounted in the same hierarchy and > not get in the way unless specifically configured - making blk-throtl > hierarchical would need this to flip the meaning of limits, cpuset to > allow tasks to run by default in new cgroups and handle empty cpusets > in a way friendly to being co-mounted, and so on. > > This patchset contains the following four patches. > > 0001-cgroup-convert-cgroupfs_root-flag-bits-to-masks-and-.patch > 0002-move-cgroupfs_root-to-include-linux-cgroup.h.patch > 0003-cgroup-introduce-sane_behavior-mount-option.patch > 0004-memcg-force-use_hierarchy-if-sane_behavior.patch > > 0001-0002 are prep patches. It exposes cgroupfs_root in cgroup.h so > that flags can be tested with inline helpers. > > 0003 introduces sane_behavior mount option and implements behavior > changes in cgroup core proper. > > 0004 makes memcg .use_hierarchy changes. > Looks good to me! Acked-by: Li Zefan <lizefan@xxxxxxxxxx> _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/containers
