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authorColin Cross <ccross@android.com>2010-11-23 21:37:03 -0800
committerColin Cross <ccross@android.com>2010-12-17 17:01:49 -0800
commit60cdbd1f3397f12b563cfc83055d443409c609eb (patch)
treed86bb3e709be07b248dfe622753d7f01aa14bc39 /kernel
parenta05f03bf6ece7619877d6b3ccfbc7597f6df7b40 (diff)
cgroup: Set CGRP_RELEASABLE when adding to a cgroup
Changes the meaning of CGRP_RELEASABLE to be set on any cgroup that has ever had a task or cgroup in it, or had css_get called on it. The bit is set in cgroup_attach_task, cgroup_create, and __css_get. It is not necessary to set the bit in cgroup_fork, as the task is either in the root cgroup, in which can never be released, or the task it was forked from already set the bit in croup_attach_task. Signed-off-by: Colin Cross <ccross@android.com>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/cgroup.c54
1 files changed, 23 insertions, 31 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index b90316504417..c2ba4e9c7f95 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -335,7 +335,15 @@ static void free_css_set_rcu(struct rcu_head *obj)
* compiled into their kernel but not actually in use */
static int use_task_css_set_links __read_mostly;
-static void __put_css_set(struct css_set *cg, int taskexit)
+/*
+ * refcounted get/put for css_set objects
+ */
+static inline void get_css_set(struct css_set *cg)
+{
+ atomic_inc(&cg->refcount);
+}
+
+static void put_css_set(struct css_set *cg)
{
struct cg_cgroup_link *link;
struct cg_cgroup_link *saved_link;
@@ -361,12 +369,8 @@ static void __put_css_set(struct css_set *cg, int taskexit)
struct cgroup *cgrp = link->cgrp;
list_del(&link->cg_link_list);
list_del(&link->cgrp_link_list);
- if (atomic_dec_and_test(&cgrp->count) &&
- notify_on_release(cgrp)) {
- if (taskexit)
- set_bit(CGRP_RELEASABLE, &cgrp->flags);
+ if (atomic_dec_and_test(&cgrp->count))
check_for_release(cgrp);
- }
kfree(link);
}
@@ -376,24 +380,6 @@ static void __put_css_set(struct css_set *cg, int taskexit)
}
/*
- * refcounted get/put for css_set objects
- */
-static inline void get_css_set(struct css_set *cg)
-{
- atomic_inc(&cg->refcount);
-}
-
-static inline void put_css_set(struct css_set *cg)
-{
- __put_css_set(cg, 0);
-}
-
-static inline void put_css_set_taskexit(struct css_set *cg)
-{
- __put_css_set(cg, 1);
-}
-
-/*
* compare_css_sets - helper function for find_existing_css_set().
* @cg: candidate css_set being tested
* @old_cg: existing css_set for a task
@@ -1773,7 +1759,7 @@ int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
if (ss->attach)
ss->attach(ss, cgrp, oldcgrp, tsk, false);
}
- set_bit(CGRP_RELEASABLE, &oldcgrp->flags);
+ set_bit(CGRP_RELEASABLE, &cgrp->flags);
synchronize_rcu();
put_css_set(cg);
@@ -3361,6 +3347,8 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
if (err < 0)
goto err_remove;
+ set_bit(CGRP_RELEASABLE, &parent->flags);
+
/* The cgroup directory was pre-locked for us */
BUG_ON(!mutex_is_locked(&cgrp->dentry->d_inode->i_mutex));
@@ -3579,7 +3567,6 @@ again:
cgroup_d_remove_dir(d);
dput(d);
- set_bit(CGRP_RELEASABLE, &parent->flags);
check_for_release(parent);
/*
@@ -4174,7 +4161,7 @@ void cgroup_exit(struct task_struct *tsk, int run_callbacks)
tsk->cgroups = &init_css_set;
task_unlock(tsk);
if (cg)
- put_css_set_taskexit(cg);
+ put_css_set(cg);
}
/**
@@ -4344,6 +4331,14 @@ static void check_for_release(struct cgroup *cgrp)
}
/* Caller must verify that the css is not for root cgroup */
+void __css_get(struct cgroup_subsys_state *css, int count)
+{
+ atomic_add(count, &css->refcnt);
+ set_bit(CGRP_RELEASABLE, &css->cgroup->flags);
+}
+EXPORT_SYMBOL_GPL(__css_get);
+
+/* Caller must verify that the css is not for root cgroup */
void __css_put(struct cgroup_subsys_state *css, int count)
{
struct cgroup *cgrp = css->cgroup;
@@ -4351,10 +4346,7 @@ void __css_put(struct cgroup_subsys_state *css, int count)
rcu_read_lock();
val = atomic_sub_return(count, &css->refcnt);
if (val == 1) {
- if (notify_on_release(cgrp)) {
- set_bit(CGRP_RELEASABLE, &cgrp->flags);
- check_for_release(cgrp);
- }
+ check_for_release(cgrp);
cgroup_wakeup_rmdir_waiter(cgrp);
}
rcu_read_unlock();