diff options
| author | Tejun Heo <tj@kernel.org> | 2014-05-16 19:22:52 +0200 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2014-05-16 19:22:52 +0200 |
| commit | f3d4650015301d1c880df4523f7e7ef320a38aab (patch) | |
| tree | ed6040e2019347e8bf9525c15db859737ecae709 /kernel/cgroup.c | |
| parent | cgroup: use CSS_ONLINE instead of CGRP_DEAD (diff) | |
| download | linux-f3d4650015301d1c880df4523f7e7ef320a38aab.tar.xz linux-f3d4650015301d1c880df4523f7e7ef320a38aab.zip | |
cgroup: convert cgroup_has_live_children() into css_has_online_children()
Now that cgroup liveliness and css onliness are the same state,
convert cgroup_has_live_children() into css_has_online_children() so
that it can be used for actual csses too. The function now uses
css_for_each_child() for iteration and is published.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Diffstat (limited to 'kernel/cgroup.c')
| -rw-r--r-- | kernel/cgroup.c | 32 |
1 files changed, 20 insertions, 12 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 004004fd0ded..082bb842b11a 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -175,7 +175,6 @@ static int need_forkexit_callback __read_mostly; static struct cftype cgroup_base_files[]; static void cgroup_put(struct cgroup *cgrp); -static bool cgroup_has_live_children(struct cgroup *cgrp); static int rebind_subsystems(struct cgroup_root *dst_root, unsigned int ss_mask); static int cgroup_destroy_locked(struct cgroup *cgrp); @@ -1769,7 +1768,7 @@ static void cgroup_kill_sb(struct super_block *sb) * This prevents new mounts by disabling percpu_ref_tryget_live(). * cgroup_mount() may wait for @root's release. */ - if (cgroup_has_live_children(&root->cgrp)) + if (css_has_online_children(&root->cgrp.self)) cgroup_put(&root->cgrp); else percpu_ref_kill(&root->cgrp.self.refcnt); @@ -3291,19 +3290,28 @@ css_next_descendant_post(struct cgroup_subsys_state *pos, return pos->parent; } -static bool cgroup_has_live_children(struct cgroup *cgrp) +/** + * css_has_online_children - does a css have online children + * @css: the target css + * + * Returns %true if @css has any online children; otherwise, %false. This + * function can be called from any context but the caller is responsible + * for synchronizing against on/offlining as necessary. + */ +bool css_has_online_children(struct cgroup_subsys_state *css) { - struct cgroup *child; + struct cgroup_subsys_state *child; + bool ret = false; rcu_read_lock(); - list_for_each_entry_rcu(child, &cgrp->self.children, self.sibling) { - if (!cgroup_is_dead(child)) { - rcu_read_unlock(); - return true; + css_for_each_child(child, css) { + if (css->flags & CSS_ONLINE) { + ret = true; + break; } } rcu_read_unlock(); - return false; + return ret; } /** @@ -4535,7 +4543,7 @@ static int cgroup_destroy_locked(struct cgroup *cgrp) * ->self.children as dead children linger on it while being * drained; otherwise, "rmdir parent/child parent" may fail. */ - if (cgroup_has_live_children(cgrp)) + if (css_has_online_children(&cgrp->self)) return -EBUSY; /* @@ -5014,8 +5022,8 @@ void cgroup_exit(struct task_struct *tsk) static void check_for_release(struct cgroup *cgrp) { - if (cgroup_is_releasable(cgrp) && - list_empty(&cgrp->cset_links) && !cgroup_has_live_children(cgrp)) { + if (cgroup_is_releasable(cgrp) && list_empty(&cgrp->cset_links) && + !css_has_online_children(&cgrp->self)) { /* * Control Group is currently removeable. If it's not * already queued for a userspace notification, queue |