On Tue 06-11-12 12:31:54, Tejun Heo wrote: > On Sat, Nov 03, 2012 at 01:38:29AM -0700, Tejun Heo wrote: > > Currently, cgroup doesn't provide any generic helper for walking a > > given cgroup's children or descendants. This patch adds the following > > three macros. > > > > * cgroup_for_each_child() - walk immediate children of a cgroup. > > > > * cgroup_for_each_descendant_pre() - visit all descendants of a cgroup > > in pre-order tree traversal. > > > > * cgroup_for_each_descendant_post() - visit all descendants of a > > cgroup in post-order tree traversal. > > > > All three only require the user to hold RCU read lock during > > traversal. Verifying that each iterated cgroup is online is the > > responsibility of the user. When used with proper synchronization, > > cgroup_for_each_descendant_pre() can be used to propagate config > > updates to descendants in reliable way. See comments for details. > > Michal, Li, how does this look to you? Would this be okay for memcg > too? Yes, definitely. We are currently iterating by css->id which is, ehm, impractical. Having a deterministic tree walk is definitely a plus. -- Michal Hocko SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
