/* reference count */
refcount_t refcount;
+ /*
+ * For a domain cgroup, the following points to self. If threaded,
+ * to the matching cset of the nearest domain ancestor. The
+ * dom_cset provides access to the domain cgroup and its csses to
+ * which domain level resource consumptions should be charged.
+ */
+ struct css_set *dom_cset;
+
/* the default cgroup associated with this css_set */
struct cgroup *dfl_cgrp;
*/
struct list_head e_cset_node[CGROUP_SUBSYS_COUNT];
+ /* all threaded csets whose ->dom_cset points to this cset */
+ struct list_head threaded_csets;
+ struct list_head threaded_csets_node;
+
/*
* List running through all cgroup groups in the same hash
* slot. Protected by css_set_lock
* doesn't have any tasks.
*
* All children which have non-zero nr_populated_csets and/or
- * nr_populated_children of their own contribute one to
- * nr_populated_children. The counter is zero iff this cgroup's
- * subtree proper doesn't have any tasks.
+ * nr_populated_children of their own contribute one to either
+ * nr_populated_domain_children or nr_populated_threaded_children
+ * depending on their type. Each counter is zero iff all cgroups
+ * of the type in the subtree proper don't have any tasks.
*/
int nr_populated_csets;
- int nr_populated_children;
+ int nr_populated_domain_children;
+ int nr_populated_threaded_children;
+
+ int nr_threaded_children; /* # of live threaded child cgroups */
struct kernfs_node *kn; /* cgroup kernfs entry */
struct cgroup_file procs_file; /* handle for "cgroup.procs" */
struct list_head e_csets[CGROUP_SUBSYS_COUNT];
/*
+ * If !threaded, self. If threaded, it points to the nearest
+ * domain ancestor. Inside a threaded subtree, cgroups are exempt
+ * from process granularity and no-internal-task constraint.
+ * Domain level resource consumptions which aren't tied to a
+ * specific task are charged to the dom_cgrp.
+ */
+ struct cgroup *dom_cgrp;
+
+ /*
* list of pidlists, up to two for each namespace (one for procs, one
* for tasks); created on demand.
*/
return cgrp->nr_populated_csets;
}
+static bool cgroup_is_threaded(struct cgroup *cgrp)
+{
+ return cgrp->dom_cgrp != cgrp;
+}
+
/* subsystems visibly enabled on a cgroup */
static u16 cgroup_control(struct cgroup *cgrp)
{
*/
struct css_set init_css_set = {
.refcount = REFCOUNT_INIT(1),
+ .dom_cset = &init_css_set,
.tasks = LIST_HEAD_INIT(init_css_set.tasks),
.mg_tasks = LIST_HEAD_INIT(init_css_set.mg_tasks),
.task_iters = LIST_HEAD_INIT(init_css_set.task_iters),
+ .threaded_csets = LIST_HEAD_INIT(init_css_set.threaded_csets),
.cgrp_links = LIST_HEAD_INIT(init_css_set.cgrp_links),
.mg_preload_node = LIST_HEAD_INIT(init_css_set.mg_preload_node),
.mg_node = LIST_HEAD_INIT(init_css_set.mg_node),
static int css_set_count = 1; /* 1 for init_css_set */
+static bool css_set_threaded(struct css_set *cset)
+{
+ return cset->dom_cset != cset;
+}
+
/**
* css_set_populated - does a css_set contain any tasks?
* @cset: target css_set
do {
bool was_populated = cgroup_is_populated(cgrp);
- if (!child)
+ if (!child) {
cgrp->nr_populated_csets += adj;
- else
- cgrp->nr_populated_children += adj;
+ } else {
+ if (cgroup_is_threaded(child))
+ cgrp->nr_populated_threaded_children += adj;
+ else
+ cgrp->nr_populated_domain_children += adj;
+ }
if (was_populated == cgroup_is_populated(cgrp))
break;
if (!refcount_dec_and_test(&cset->refcount))
return;
+ WARN_ON_ONCE(!list_empty(&cset->threaded_csets));
+
/* This css_set is dead. unlink it and release cgroup and css refs */
for_each_subsys(ss, ssid) {
list_del(&cset->e_cset_node[ssid]);
kfree(link);
}
+ if (css_set_threaded(cset)) {
+ list_del(&cset->threaded_csets_node);
+ put_css_set_locked(cset->dom_cset);
+ }
+
kfree_rcu(cset, rcu_head);
}
struct cgroup *new_cgrp,
struct cgroup_subsys_state *template[])
{
+ struct cgroup *new_dfl_cgrp;
struct list_head *l1, *l2;
/*
if (memcmp(template, cset->subsys, sizeof(cset->subsys)))
return false;
+
+ /* @cset's domain should match the default cgroup's */
+ if (cgroup_on_dfl(new_cgrp))
+ new_dfl_cgrp = new_cgrp;
+ else
+ new_dfl_cgrp = old_cset->dfl_cgrp;
+
+ if (new_dfl_cgrp->dom_cgrp != cset->dom_cset->dfl_cgrp)
+ return false;
+
/*
* Compare cgroup pointers in order to distinguish between
* different cgroups in hierarchies. As different cgroups may
}
refcount_set(&cset->refcount, 1);
+ cset->dom_cset = cset;
INIT_LIST_HEAD(&cset->tasks);
INIT_LIST_HEAD(&cset->mg_tasks);
INIT_LIST_HEAD(&cset->task_iters);
+ INIT_LIST_HEAD(&cset->threaded_csets);
INIT_HLIST_NODE(&cset->hlist);
INIT_LIST_HEAD(&cset->cgrp_links);
INIT_LIST_HEAD(&cset->mg_preload_node);
spin_unlock_irq(&css_set_lock);
+ /*
+ * If @cset should be threaded, look up the matching dom_cset and
+ * link them up. We first fully initialize @cset then look for the
+ * dom_cset. It's simpler this way and safe as @cset is guaranteed
+ * to stay empty until we return.
+ */
+ if (cgroup_is_threaded(cset->dfl_cgrp)) {
+ struct css_set *dcset;
+
+ dcset = find_css_set(cset, cset->dfl_cgrp->dom_cgrp);
+ if (!dcset) {
+ put_css_set(cset);
+ return NULL;
+ }
+
+ spin_lock_irq(&css_set_lock);
+ cset->dom_cset = dcset;
+ list_add_tail(&cset->threaded_csets_node,
+ &dcset->threaded_csets);
+ spin_unlock_irq(&css_set_lock);
+ }
+
return cset;
}
mutex_init(&cgrp->pidlist_mutex);
cgrp->self.cgroup = cgrp;
cgrp->self.flags |= CSS_ONLINE;
+ cgrp->dom_cgrp = cgrp;
for_each_subsys(ss, ssid)
INIT_LIST_HEAD(&cgrp->e_csets[ssid]);
static int cgroup_destroy_locked(struct cgroup *cgrp)
__releases(&cgroup_mutex) __acquires(&cgroup_mutex)
{
+ struct cgroup *parent = cgroup_parent(cgrp);
struct cgroup_subsys_state *css;
struct cgrp_cset_link *link;
int ssid;
*/
kernfs_remove(cgrp->kn);
+ if (parent && cgroup_is_threaded(cgrp))
+ parent->nr_threaded_children--;
+
cgroup1_check_for_release(cgroup_parent(cgrp));
/* put the base reference */