summaryrefslogtreecommitdiff
path: root/kernel/cgroup.c
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2016-02-10 11:36:19 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2016-02-10 11:36:19 -0800
commitfb0dc5f129bc2d4763bdc237b8df0e1708c03e1e (patch)
tree4c635f1ca11535c0072d2f10282a31d16979d639 /kernel/cgroup.c
parent9aece75c138d93bde79a2baeb9187a1109b4e952 (diff)
parent9a2ddda572a002633a64b1ae5f4bc49cfcbf495f (diff)
Merge branch 'for-4.5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup fixes from Tejun Heo: - The destruction path of cgroup objects are asynchronous and multi-staged and some of them ended up destroying parents before children leading to failures in cpu and memory controllers. Ensure that parents are always destroyed after children. - cpuset mm node migration was performed synchronously while holding threadgroup and cgroup mutexes and the recent threadgroup locking update resulted in a possible deadlock. The migration is best effort and shouldn't have been performed under those locks to begin with. Made asynchronous. - Minor documentation fix. * 'for-4.5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: Documentation: cgroup: Fix 'cgroup-legacy' -> 'cgroup-v1' cgroup: make sure a parent css isn't freed before its children cgroup: make sure a parent css isn't offlined before its children cpuset: make mm migration asynchronous
Diffstat (limited to 'kernel/cgroup.c')
-rw-r--r--kernel/cgroup.c31
1 files changed, 23 insertions, 8 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index c03a640ef6da..d27904c193da 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -58,6 +58,7 @@
#include <linux/kthread.h>
#include <linux/delay.h>
#include <linux/atomic.h>
+#include <linux/cpuset.h>
#include <net/sock.h>
/*
@@ -2739,6 +2740,7 @@ out_unlock_rcu:
out_unlock_threadgroup:
percpu_up_write(&cgroup_threadgroup_rwsem);
cgroup_kn_unlock(of->kn);
+ cpuset_post_attach_flush();
return ret ?: nbytes;
}
@@ -4655,14 +4657,15 @@ static void css_free_work_fn(struct work_struct *work)
if (ss) {
/* css free path */
+ struct cgroup_subsys_state *parent = css->parent;
int id = css->id;
- if (css->parent)
- css_put(css->parent);
-
ss->css_free(css);
cgroup_idr_remove(&ss->css_idr, id);
cgroup_put(cgrp);
+
+ if (parent)
+ css_put(parent);
} else {
/* cgroup free path */
atomic_dec(&cgrp->root->nr_cgrps);
@@ -4758,6 +4761,7 @@ static void init_and_link_css(struct cgroup_subsys_state *css,
INIT_LIST_HEAD(&css->sibling);
INIT_LIST_HEAD(&css->children);
css->serial_nr = css_serial_nr_next++;
+ atomic_set(&css->online_cnt, 0);
if (cgroup_parent(cgrp)) {
css->parent = cgroup_css(cgroup_parent(cgrp), ss);
@@ -4780,6 +4784,10 @@ static int online_css(struct cgroup_subsys_state *css)
if (!ret) {
css->flags |= CSS_ONLINE;
rcu_assign_pointer(css->cgroup->subsys[ss->id], css);
+
+ atomic_inc(&css->online_cnt);
+ if (css->parent)
+ atomic_inc(&css->parent->online_cnt);
}
return ret;
}
@@ -5017,10 +5025,15 @@ static void css_killed_work_fn(struct work_struct *work)
container_of(work, struct cgroup_subsys_state, destroy_work);
mutex_lock(&cgroup_mutex);
- offline_css(css);
- mutex_unlock(&cgroup_mutex);
- css_put(css);
+ do {
+ offline_css(css);
+ css_put(css);
+ /* @css can't go away while we're holding cgroup_mutex */
+ css = css->parent;
+ } while (css && atomic_dec_and_test(&css->online_cnt));
+
+ mutex_unlock(&cgroup_mutex);
}
/* css kill confirmation processing requires process context, bounce */
@@ -5029,8 +5042,10 @@ static void css_killed_ref_fn(struct percpu_ref *ref)
struct cgroup_subsys_state *css =
container_of(ref, struct cgroup_subsys_state, refcnt);
- INIT_WORK(&css->destroy_work, css_killed_work_fn);
- queue_work(cgroup_destroy_wq, &css->destroy_work);
+ if (atomic_dec_and_test(&css->online_cnt)) {
+ INIT_WORK(&css->destroy_work, css_killed_work_fn);
+ queue_work(cgroup_destroy_wq, &css->destroy_work);
+ }
}
/**