diff options
| -rw-r--r-- | include/linux/cgroup.h | 16 | ||||
| -rw-r--r-- | kernel/cgroup.c | 20 |
2 files changed, 19 insertions, 17 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index cf8ba26..ebe7ce4 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -80,6 +80,14 @@ struct cgroup_subsys_state { unsigned int flags; + /* + * Monotonically increasing unique serial number which defines a + * uniform order among all csses. It's guaranteed that all + * ->children lists are in the ascending order of ->serial_nr and + * used to allow interrupting and resuming iterations. + */ + u64 serial_nr; + /* percpu_ref killing and RCU release */ struct rcu_head rcu_head; struct work_struct destroy_work; @@ -178,14 +186,6 @@ struct cgroup { struct kernfs_node *kn; /* cgroup kernfs entry */ struct kernfs_node *populated_kn; /* kn for "cgroup.subtree_populated" */ - /* - * Monotonically increasing unique serial number which defines a - * uniform order among all cgroups. It's guaranteed that all - * ->children lists are in the ascending order of ->serial_nr. - * It's used to allow interrupting and resuming iterations. - */ - u64 serial_nr; - /* the bitmask of subsystems enabled on the child cgroups */ unsigned int child_subsys_mask; diff --git a/kernel/cgroup.c b/kernel/cgroup.c index dcb06e1..d5af128 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -157,14 +157,13 @@ static int cgroup_root_count; static DEFINE_IDR(cgroup_hierarchy_idr); /* - * Assign a monotonically increasing serial number to cgroups. It - * guarantees cgroups with bigger numbers are newer than those with smaller - * numbers. Also, as cgroups are always appended to the parent's - * ->children list, it guarantees that sibling cgroups are always sorted in - * the ascending serial number order on the list. Protected by - * cgroup_mutex. + * Assign a monotonically increasing serial number to csses. It guarantees + * cgroups with bigger numbers are newer than those with smaller numbers. + * Also, as csses are always appended to the parent's ->children list, it + * guarantees that sibling csses are always sorted in the ascending serial + * number order on the list. Protected by cgroup_mutex. */ -static u64 cgroup_serial_nr_next = 1; +static u64 css_serial_nr_next = 1; /* This flag indicates whether tasks in the fork and exit paths should * check for fork/exit handlers to call. This avoids us having to do @@ -3133,7 +3132,7 @@ css_next_child(struct cgroup_subsys_state *pos_css, next = list_entry_rcu(pos->self.sibling.next, struct cgroup, self.sibling); } else { list_for_each_entry_rcu(next, &cgrp->self.children, self.sibling) - if (next->serial_nr > pos->serial_nr) + if (next->self.serial_nr > pos->self.serial_nr) break; } @@ -4168,6 +4167,8 @@ static void css_release(struct percpu_ref *ref) static void init_and_link_css(struct cgroup_subsys_state *css, struct cgroup_subsys *ss, struct cgroup *cgrp) { + lockdep_assert_held(&cgroup_mutex); + cgroup_get(cgrp); memset(css, 0, sizeof(*css)); @@ -4175,6 +4176,7 @@ static void init_and_link_css(struct cgroup_subsys_state *css, css->ss = ss; INIT_LIST_HEAD(&css->sibling); INIT_LIST_HEAD(&css->children); + css->serial_nr = css_serial_nr_next++; if (cgroup_parent(cgrp)) { css->parent = cgroup_css(cgroup_parent(cgrp), ss); @@ -4348,7 +4350,7 @@ static int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name, */ kernfs_get(kn); - cgrp->serial_nr = cgroup_serial_nr_next++; + cgrp->self.serial_nr = css_serial_nr_next++; /* allocation complete, commit to creation */ list_add_tail_rcu(&cgrp->self.sibling, &cgroup_parent(cgrp)->self.children); |
