From 2d8f243a5e6efa57fb7c46fe83fafa45b33d0ec2 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Wed, 23 Apr 2014 11:13:15 -0400 Subject: cgroup: implement cgroup->e_csets[] On the default unified hierarchy, a cgroup may be associated with csses of its ancestors, which means that a css of a given cgroup may be associated with css_sets of descendant cgroups. This means that we can't walk all tasks associated with a css by iterating the css_sets associated with the cgroup as there are css_sets which are pointing to the css but linked on the descendants. This patch adds per-subsystem list heads cgroup->e_csets[]. Any css_set which is pointing to a css is linked to css->cgroup->e_csets[$SUBSYS_ID] through css_set->e_cset_node[$SUBSYS_ID]. The lists are protected by css_set_rwsem and will allow us to walk all css_sets associated with a given css so that we can find out all associated tasks. Signed-off-by: Tejun Heo Acked-by: Li Zefan --- include/linux/cgroup.h | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'include') diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index 1b5b2fe1b228..33a0043ef454 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -187,6 +187,15 @@ struct cgroup { */ struct list_head cset_links; + /* + * On the default hierarchy, a css_set for a cgroup with some + * susbsys disabled will point to css's which are associated with + * the closest ancestor which has the subsys enabled. The + * following lists all css_sets which point to this cgroup's css + * for the given subsystem. + */ + struct list_head e_csets[CGROUP_SUBSYS_COUNT]; + /* * Linked list running through all cgroups that can * potentially be reaped by the release agent. Protected by @@ -369,6 +378,15 @@ struct css_set { struct cgroup *mg_src_cgrp; struct css_set *mg_dst_cset; + /* + * On the default hierarhcy, ->subsys[ssid] may point to a css + * attached to an ancestor instead of the cgroup this css_set is + * associated with. The following node is anchored at + * ->subsys[ssid]->cgroup->e_csets[ssid] and provides a way to + * iterate through all css's attached to a given cgroup. + */ + struct list_head e_cset_node[CGROUP_SUBSYS_COUNT]; + /* For RCU-protected deletion */ struct rcu_head rcu_head; }; -- cgit v1.2.3