static struct cftype cgroup_dfl_base_files[];
static struct cftype cgroup_legacy_base_files[];
-static void cgroup_put(struct cgroup *cgrp);
static int rebind_subsystems(struct cgroup_root *dst_root,
unsigned int ss_mask);
static int cgroup_destroy_locked(struct cgroup *cgrp);
static void kill_css(struct cgroup_subsys_state *css);
static int cgroup_addrm_files(struct cgroup *cgrp, struct cftype cfts[],
bool is_add);
-static void cgroup_pidlist_destroy_all(struct cgroup *cgrp);
/* IDR wrappers which synchronize using cgroup_idr_lock */
static int cgroup_idr_alloc(struct idr *idr, void *ptr, int start, int end,
if (!(cgrp->root->subsys_mask & (1 << ss->id)))
return NULL;
+ /*
+ * This function is used while updating css associations and thus
+ * can't test the csses directly. Use ->child_subsys_mask.
+ */
while (cgroup_parent(cgrp) &&
!(cgroup_parent(cgrp)->child_subsys_mask & (1 << ss->id)))
cgrp = cgroup_parent(cgrp);
return cgroup_css(cgrp, ss);
}
+/**
+ * cgroup_get_e_css - get a cgroup's effective css for the specified subsystem
+ * @cgrp: the cgroup of interest
+ * @ss: the subsystem of interest
+ *
+ * Find and get the effective css of @cgrp for @ss. The effective css is
+ * defined as the matching css of the nearest ancestor including self which
+ * has @ss enabled. If @ss is not mounted on the hierarchy @cgrp is on,
+ * the root css is returned, so this function always returns a valid css.
+ * The returned css must be put using css_put().
+ */
+struct cgroup_subsys_state *cgroup_get_e_css(struct cgroup *cgrp,
+ struct cgroup_subsys *ss)
+{
+ struct cgroup_subsys_state *css;
+
+ rcu_read_lock();
+
+ do {
+ css = cgroup_css(cgrp, ss);
+
+ if (css && css_tryget_online(css))
+ goto out_unlock;
+ cgrp = cgroup_parent(cgrp);
+ } while (cgrp);
+
+ css = init_css_set.subsys[ss->id];
+ css_get(css);
+out_unlock:
+ rcu_read_unlock();
+ return css;
+}
+
/* convenient tests for these bits */
static inline bool cgroup_is_dead(const struct cgroup *cgrp)
{
return false;
}
-static int cgroup_is_releasable(const struct cgroup *cgrp)
-{
- const int bits =
- (1 << CGRP_RELEASABLE) |
- (1 << CGRP_NOTIFY_ON_RELEASE);
- return (cgrp->flags & bits) == bits;
-}
-
static int notify_on_release(const struct cgroup *cgrp)
{
return test_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
; \
else
-/* the list of cgroups eligible for automatic release. Protected by
- * release_list_lock */
-static LIST_HEAD(release_list);
-static DEFINE_RAW_SPINLOCK(release_list_lock);
static void cgroup_release_agent(struct work_struct *work);
-static DECLARE_WORK(release_agent_work, cgroup_release_agent);
static void check_for_release(struct cgroup *cgrp);
/*
return key;
}
-static void put_css_set_locked(struct css_set *cset, bool taskexit)
+static void put_css_set_locked(struct css_set *cset)
{
struct cgrp_cset_link *link, *tmp_link;
struct cgroup_subsys *ss;
/* @cgrp can't go away while we're holding css_set_rwsem */
if (list_empty(&cgrp->cset_links)) {
cgroup_update_populated(cgrp, false);
- if (notify_on_release(cgrp)) {
- if (taskexit)
- set_bit(CGRP_RELEASABLE, &cgrp->flags);
- check_for_release(cgrp);
- }
+ check_for_release(cgrp);
}
kfree(link);
kfree_rcu(cset, rcu_head);
}
-static void put_css_set(struct css_set *cset, bool taskexit)
+static void put_css_set(struct css_set *cset)
{
/*
* Ensure that the refcount doesn't hit zero while any readers
return;
down_write(&css_set_rwsem);
- put_css_set_locked(cset, taskexit);
+ put_css_set_locked(cset);
up_write(&css_set_rwsem);
}
* knows that the cgroup won't be removed, as cgroup_rmdir()
* needs that mutex.
*
- * The fork and exit callbacks cgroup_fork() and cgroup_exit(), don't
- * (usually) take cgroup_mutex. These are the two most performance
- * critical pieces of code here. The exception occurs on cgroup_exit(),
- * when a task in a notify_on_release cgroup exits. Then cgroup_mutex
- * is taken, and if the cgroup count is zero, a usermode call made
- * to the release agent with the name of the cgroup (path relative to
- * the root of cgroup file system) as the argument.
- *
* A cgroup can only be deleted if both its 'count' of using tasks
* is zero, and its list of 'children' cgroups is empty. Since all
* tasks in the system use _some_ cgroup, and since there is always at
}
/**
- * cgroup_refresh_child_subsys_mask - update child_subsys_mask
+ * cgroup_calc_child_subsys_mask - calculate child_subsys_mask
* @cgrp: the target cgroup
+ * @subtree_control: the new subtree_control mask to consider
*
* On the default hierarchy, a subsystem may request other subsystems to be
* enabled together through its ->depends_on mask. In such cases, more
* subsystems than specified in "cgroup.subtree_control" may be enabled.
*
- * This function determines which subsystems need to be enabled given the
- * current @cgrp->subtree_control and records it in
- * @cgrp->child_subsys_mask. The resulting mask is always a superset of
- * @cgrp->subtree_control and follows the usual hierarchy rules.
+ * This function calculates which subsystems need to be enabled if
+ * @subtree_control is to be applied to @cgrp. The returned mask is always
+ * a superset of @subtree_control and follows the usual hierarchy rules.
*/
-static void cgroup_refresh_child_subsys_mask(struct cgroup *cgrp)
+static unsigned int cgroup_calc_child_subsys_mask(struct cgroup *cgrp,
+ unsigned int subtree_control)
{
struct cgroup *parent = cgroup_parent(cgrp);
- unsigned int cur_ss_mask = cgrp->subtree_control;
+ unsigned int cur_ss_mask = subtree_control;
struct cgroup_subsys *ss;
int ssid;
lockdep_assert_held(&cgroup_mutex);
- if (!cgroup_on_dfl(cgrp)) {
- cgrp->child_subsys_mask = cur_ss_mask;
- return;
- }
+ if (!cgroup_on_dfl(cgrp))
+ return cur_ss_mask;
while (true) {
unsigned int new_ss_mask = cur_ss_mask;
cur_ss_mask = new_ss_mask;
}
- cgrp->child_subsys_mask = cur_ss_mask;
+ return cur_ss_mask;
+}
+
+/**
+ * cgroup_refresh_child_subsys_mask - update child_subsys_mask
+ * @cgrp: the target cgroup
+ *
+ * Update @cgrp->child_subsys_mask according to the current
+ * @cgrp->subtree_control using cgroup_calc_child_subsys_mask().
+ */
+static void cgroup_refresh_child_subsys_mask(struct cgroup *cgrp)
+{
+ cgrp->child_subsys_mask =
+ cgroup_calc_child_subsys_mask(cgrp, cgrp->subtree_control);
}
/**
INIT_LIST_HEAD(&cgrp->self.sibling);
INIT_LIST_HEAD(&cgrp->self.children);
INIT_LIST_HEAD(&cgrp->cset_links);
- INIT_LIST_HEAD(&cgrp->release_list);
INIT_LIST_HEAD(&cgrp->pidlists);
mutex_init(&cgrp->pidlist_mutex);
cgrp->self.cgroup = cgrp;
INIT_LIST_HEAD(&cgrp->e_csets[ssid]);
init_waitqueue_head(&cgrp->offline_waitq);
+ INIT_WORK(&cgrp->release_agent_work, cgroup_release_agent);
}
static void init_cgroup_root(struct cgroup_root *root,
goto out;
root_cgrp->id = ret;
- ret = percpu_ref_init(&root_cgrp->self.refcnt, css_release);
+ ret = percpu_ref_init(&root_cgrp->self.refcnt, css_release, 0,
+ GFP_KERNEL);
if (ret)
goto out;
* task. As trading it for new_cset is protected by cgroup_mutex,
* we're safe to drop it here; it will be freed under RCU.
*/
- set_bit(CGRP_RELEASABLE, &old_cgrp->flags);
- put_css_set_locked(old_cset, false);
+ put_css_set_locked(old_cset);
}
/**
cset->mg_src_cgrp = NULL;
cset->mg_dst_cset = NULL;
list_del_init(&cset->mg_preload_node);
- put_css_set_locked(cset, false);
+ put_css_set_locked(cset);
}
up_write(&css_set_rwsem);
}
if (src_cset == dst_cset) {
src_cset->mg_src_cgrp = NULL;
list_del_init(&src_cset->mg_preload_node);
- put_css_set(src_cset, false);
- put_css_set(dst_cset, false);
+ put_css_set(src_cset);
+ put_css_set(dst_cset);
continue;
}
if (list_empty(&dst_cset->mg_preload_node))
list_add(&dst_cset->mg_preload_node, &csets);
else
- put_css_set(dst_cset, false);
+ put_css_set(dst_cset);
}
list_splice_tail(&csets, preloaded_csets);
loff_t off)
{
unsigned int enable = 0, disable = 0;
- unsigned int css_enable, css_disable, old_ctrl, new_ctrl;
+ unsigned int css_enable, css_disable, old_sc, new_sc, old_ss, new_ss;
struct cgroup *cgrp, *child;
struct cgroup_subsys *ss;
char *tok;
ret = -ENOENT;
goto out_unlock;
}
-
- /*
- * @ss is already enabled through dependency and
- * we'll just make it visible. Skip draining.
- */
- if (cgrp->child_subsys_mask & (1 << ssid))
- continue;
-
- /*
- * Because css offlining is asynchronous, userland
- * might try to re-enable the same controller while
- * the previous instance is still around. In such
- * cases, wait till it's gone using offline_waitq.
- */
- cgroup_for_each_live_child(child, cgrp) {
- DEFINE_WAIT(wait);
-
- if (!cgroup_css(child, ss))
- continue;
-
- cgroup_get(child);
- prepare_to_wait(&child->offline_waitq, &wait,
- TASK_UNINTERRUPTIBLE);
- cgroup_kn_unlock(of->kn);
- schedule();
- finish_wait(&child->offline_waitq, &wait);
- cgroup_put(child);
-
- return restart_syscall();
- }
} else if (disable & (1 << ssid)) {
if (!(cgrp->subtree_control & (1 << ssid))) {
disable &= ~(1 << ssid);
* subsystems than specified may need to be enabled or disabled
* depending on subsystem dependencies.
*/
- cgrp->subtree_control |= enable;
- cgrp->subtree_control &= ~disable;
-
- old_ctrl = cgrp->child_subsys_mask;
- cgroup_refresh_child_subsys_mask(cgrp);
- new_ctrl = cgrp->child_subsys_mask;
+ old_sc = cgrp->subtree_control;
+ old_ss = cgrp->child_subsys_mask;
+ new_sc = (old_sc | enable) & ~disable;
+ new_ss = cgroup_calc_child_subsys_mask(cgrp, new_sc);
- css_enable = ~old_ctrl & new_ctrl;
- css_disable = old_ctrl & ~new_ctrl;
+ css_enable = ~old_ss & new_ss;
+ css_disable = old_ss & ~new_ss;
enable |= css_enable;
disable |= css_disable;
+ /*
+ * Because css offlining is asynchronous, userland might try to
+ * re-enable the same controller while the previous instance is
+ * still around. In such cases, wait till it's gone using
+ * offline_waitq.
+ */
+ for_each_subsys(ss, ssid) {
+ if (!(css_enable & (1 << ssid)))
+ continue;
+
+ cgroup_for_each_live_child(child, cgrp) {
+ DEFINE_WAIT(wait);
+
+ if (!cgroup_css(child, ss))
+ continue;
+
+ cgroup_get(child);
+ prepare_to_wait(&child->offline_waitq, &wait,
+ TASK_UNINTERRUPTIBLE);
+ cgroup_kn_unlock(of->kn);
+ schedule();
+ finish_wait(&child->offline_waitq, &wait);
+ cgroup_put(child);
+
+ return restart_syscall();
+ }
+ }
+
+ cgrp->subtree_control = new_sc;
+ cgrp->child_subsys_mask = new_ss;
+
/*
* Create new csses or make the existing ones visible. A css is
* created invisible if it's being implicitly enabled through
}
}
+ /*
+ * The effective csses of all the descendants (excluding @cgrp) may
+ * have changed. Subsystems can optionally subscribe to this event
+ * by implementing ->css_e_css_changed() which is invoked if any of
+ * the effective csses seen from the css's cgroup may have changed.
+ */
+ for_each_subsys(ss, ssid) {
+ struct cgroup_subsys_state *this_css = cgroup_css(cgrp, ss);
+ struct cgroup_subsys_state *css;
+
+ if (!ss->css_e_css_changed || !this_css)
+ continue;
+
+ css_for_each_descendant_pre(css, this_css)
+ if (css != this_css)
+ ss->css_e_css_changed(css);
+ }
+
kernfs_activate(cgrp->kn);
ret = 0;
out_unlock:
return ret ?: nbytes;
err_undo_css:
- cgrp->subtree_control &= ~enable;
- cgrp->subtree_control |= disable;
- cgroup_refresh_child_subsys_mask(cgrp);
+ cgrp->subtree_control = old_sc;
+ cgrp->child_subsys_mask = old_ss;
for_each_subsys(ss, ssid) {
if (!(enable & (1 << ssid)))
static int cgroup_write_notify_on_release(struct cgroup_subsys_state *css,
struct cftype *cft, u64 val)
{
- clear_bit(CGRP_RELEASABLE, &css->cgroup->flags);
if (val)
set_bit(CGRP_NOTIFY_ON_RELEASE, &css->cgroup->flags);
else
/* cgroup free path */
atomic_dec(&cgrp->root->nr_cgrps);
cgroup_pidlist_destroy_all(cgrp);
+ cancel_work_sync(&cgrp->release_agent_work);
if (cgroup_parent(cgrp)) {
/*
if (ss) {
/* css release path */
cgroup_idr_remove(&ss->css_idr, css->id);
+ if (ss->css_released)
+ ss->css_released(css);
} else {
/* cgroup release path */
cgroup_idr_remove(&cgrp->root->cgroup_idr, cgrp->id);
init_and_link_css(css, ss, cgrp);
- err = percpu_ref_init(&css->refcnt, css_release);
+ err = percpu_ref_init(&css->refcnt, css_release, 0, GFP_KERNEL);
if (err)
goto err_free_css;
goto out_unlock;
}
- ret = percpu_ref_init(&cgrp->self.refcnt, css_release);
+ ret = percpu_ref_init(&cgrp->self.refcnt, css_release, 0, GFP_KERNEL);
if (ret)
goto out_free_cgrp;
for_each_css(css, ssid, cgrp)
kill_css(css);
- /* CSS_ONLINE is clear, remove from ->release_list for the last time */
- raw_spin_lock(&release_list_lock);
- if (!list_empty(&cgrp->release_list))
- list_del_init(&cgrp->release_list);
- raw_spin_unlock(&release_list_lock);
-
/*
* Remove @cgrp directory along with the base files. @cgrp has an
* extra ref on its kn.
*/
kernfs_remove(cgrp->kn);
- set_bit(CGRP_RELEASABLE, &cgroup_parent(cgrp)->flags);
check_for_release(cgroup_parent(cgrp));
/* put the base reference */
cgrp = cgroup_kn_lock_live(kn);
if (!cgrp)
return 0;
- cgroup_get(cgrp); /* for @kn->priv clearing */
ret = cgroup_destroy_locked(cgrp);
cgroup_kn_unlock(kn);
-
- cgroup_put(cgrp);
return ret;
}
* - Print task's cgroup paths into seq_file, one line for each hierarchy
* - Used for /proc/<pid>/cgroup.
*/
-
-/* TODO: Use a proper seq_file iterator */
-int proc_cgroup_show(struct seq_file *m, void *v)
+int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns,
+ struct pid *pid, struct task_struct *tsk)
{
- struct pid *pid;
- struct task_struct *tsk;
char *buf, *path;
int retval;
struct cgroup_root *root;
if (!buf)
goto out;
- retval = -ESRCH;
- pid = m->private;
- tsk = get_pid_task(pid, PIDTYPE_PID);
- if (!tsk)
- goto out_free;
-
- retval = 0;
-
mutex_lock(&cgroup_mutex);
down_read(&css_set_rwsem);
seq_putc(m, '\n');
}
+ retval = 0;
out_unlock:
up_read(&css_set_rwsem);
mutex_unlock(&cgroup_mutex);
- put_task_struct(tsk);
-out_free:
kfree(buf);
out:
return retval;
int i;
/*
- * This may race against cgroup_enable_task_cg_links(). As that
+ * This may race against cgroup_enable_task_cg_lists(). As that
* function sets use_task_css_set_links before grabbing
* tasklist_lock and we just went through tasklist_lock to add
* @child, it's guaranteed that either we see the set
* when implementing operations which need to migrate all tasks of
* a cgroup to another.
*
- * Note that if we lose to cgroup_enable_task_cg_links(), @child
+ * Note that if we lose to cgroup_enable_task_cg_lists(), @child
* will remain in init_css_set. This is safe because all tasks are
* in the init_css_set before cg_links is enabled and there's no
* operation which transfers all tasks out of init_css_set.
}
if (put_cset)
- put_css_set(cset, true);
+ put_css_set(cset);
}
static void check_for_release(struct cgroup *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
- * it now
- */
- int need_schedule_work = 0;
-
- raw_spin_lock(&release_list_lock);
- if (!cgroup_is_dead(cgrp) &&
- list_empty(&cgrp->release_list)) {
- list_add(&cgrp->release_list, &release_list);
- need_schedule_work = 1;
- }
- raw_spin_unlock(&release_list_lock);
- if (need_schedule_work)
- schedule_work(&release_agent_work);
- }
+ if (notify_on_release(cgrp) && !cgroup_has_tasks(cgrp) &&
+ !css_has_online_children(&cgrp->self) && !cgroup_is_dead(cgrp))
+ schedule_work(&cgrp->release_agent_work);
}
/*
*/
static void cgroup_release_agent(struct work_struct *work)
{
- BUG_ON(work != &release_agent_work);
+ struct cgroup *cgrp =
+ container_of(work, struct cgroup, release_agent_work);
+ char *pathbuf = NULL, *agentbuf = NULL, *path;
+ char *argv[3], *envp[3];
+
mutex_lock(&cgroup_mutex);
- raw_spin_lock(&release_list_lock);
- while (!list_empty(&release_list)) {
- char *argv[3], *envp[3];
- int i;
- char *pathbuf = NULL, *agentbuf = NULL, *path;
- struct cgroup *cgrp = list_entry(release_list.next,
- struct cgroup,
- release_list);
- list_del_init(&cgrp->release_list);
- raw_spin_unlock(&release_list_lock);
- pathbuf = kmalloc(PATH_MAX, GFP_KERNEL);
- if (!pathbuf)
- goto continue_free;
- path = cgroup_path(cgrp, pathbuf, PATH_MAX);
- if (!path)
- goto continue_free;
- agentbuf = kstrdup(cgrp->root->release_agent_path, GFP_KERNEL);
- if (!agentbuf)
- goto continue_free;
-
- i = 0;
- argv[i++] = agentbuf;
- argv[i++] = path;
- argv[i] = NULL;
-
- i = 0;
- /* minimal command environment */
- envp[i++] = "HOME=/";
- envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
- envp[i] = NULL;
-
- /* Drop the lock while we invoke the usermode helper,
- * since the exec could involve hitting disk and hence
- * be a slow process */
- mutex_unlock(&cgroup_mutex);
- call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC);
- mutex_lock(&cgroup_mutex);
- continue_free:
- kfree(pathbuf);
- kfree(agentbuf);
- raw_spin_lock(&release_list_lock);
- }
- raw_spin_unlock(&release_list_lock);
+
+ pathbuf = kmalloc(PATH_MAX, GFP_KERNEL);
+ agentbuf = kstrdup(cgrp->root->release_agent_path, GFP_KERNEL);
+ if (!pathbuf || !agentbuf)
+ goto out;
+
+ path = cgroup_path(cgrp, pathbuf, PATH_MAX);
+ if (!path)
+ goto out;
+
+ argv[0] = agentbuf;
+ argv[1] = path;
+ argv[2] = NULL;
+
+ /* minimal command environment */
+ envp[0] = "HOME=/";
+ envp[1] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
+ envp[2] = NULL;
+
mutex_unlock(&cgroup_mutex);
+ call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC);
+ goto out_free;
+out:
+ mutex_unlock(&cgroup_mutex);
+out_free:
+ kfree(agentbuf);
+ kfree(pathbuf);
}
static int __init cgroup_disable(char *str)
static u64 releasable_read(struct cgroup_subsys_state *css, struct cftype *cft)
{
- return test_bit(CGRP_RELEASABLE, &css->cgroup->flags);
+ return (!cgroup_has_tasks(css->cgroup) &&
+ !css_has_online_children(&css->cgroup->self));
}
static struct cftype debug_files[] = {
projects / deliverable / linux.git / blobdiff