From b5f99b537d047072bd50ff5c51000613eb537be8 Mon Sep 17 00:00:00 2001 From: Glauber Costa Date: Fri, 22 Feb 2013 16:34:53 -0800 Subject: [PATCH] memcg: fast hierarchy-aware child test Currently, we use cgroups' provided list of children to verify if it is safe to proceed with any value change that is dependent on the cgroup being empty. This is less than ideal, because it enforces a dependency over cgroup core that we would be better off without. The solution proposed here is to iterate over the child cgroups and if any is found that is already online, we bounce and return: we don't really care how many children we have, only if we have any. This is also made to be hierarchy aware. IOW, cgroups with hierarchy disabled, while they still exist, will be considered for the purpose of this interface as having no children. [akpm@linux-foundation.org: tweak comments] Signed-off-by: Glauber Costa Acked-by: Michal Hocko Cc: Tejun Heo Cc: Hiroyuki Kamezawa Cc: Johannes Weiner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Reading git-format-patch failed