#include <linux/vmalloc.h> /* TODO: replace with more sophisticated array */
#include <linux/kthread.h>
#include <linux/delay.h>
-
+#include <linux/cpuset.h>
#include <linux/atomic.h>
/*
*/
static bool cgroup_ssid_enabled(int ssid)
{
+ if (CGROUP_SUBSYS_COUNT == 0)
+ return false;
+
return static_key_enabled(cgroup_subsys_enabled_key[ssid]);
}
static void put_css_set(struct css_set *cset)
{
+ unsigned long flags;
+
/*
* Ensure that the refcount doesn't hit zero while any readers
* can see it. Similar to atomic_dec_and_lock(), but for an
if (atomic_add_unless(&cset->refcount, -1, 1))
return;
- spin_lock_bh(&css_set_lock);
+ spin_lock_irqsave(&css_set_lock, flags);
put_css_set_locked(cset);
- spin_unlock_bh(&css_set_lock);
+ spin_unlock_irqrestore(&css_set_lock, flags);
}
/*
/* First see if we already have a cgroup group that matches
* the desired set */
- spin_lock_bh(&css_set_lock);
+ spin_lock_irq(&css_set_lock);
cset = find_existing_css_set(old_cset, cgrp, template);
if (cset)
get_css_set(cset);
- spin_unlock_bh(&css_set_lock);
+ spin_unlock_irq(&css_set_lock);
if (cset)
return cset;
* find_existing_css_set() */
memcpy(cset->subsys, template, sizeof(cset->subsys));
- spin_lock_bh(&css_set_lock);
+ spin_lock_irq(&css_set_lock);
/* Add reference counts and links from the new css_set. */
list_for_each_entry(link, &old_cset->cgrp_links, cgrp_link) {
struct cgroup *c = link->cgrp;
css_get(css);
}
- spin_unlock_bh(&css_set_lock);
+ spin_unlock_irq(&css_set_lock);
return cset;
}
* Release all the links from cset_links to this hierarchy's
* root cgroup
*/
- spin_lock_bh(&css_set_lock);
+ spin_lock_irq(&css_set_lock);
list_for_each_entry_safe(link, tmp_link, &cgrp->cset_links, cset_link) {
list_del(&link->cset_link);
kfree(link);
}
- spin_unlock_bh(&css_set_lock);
+ spin_unlock_irq(&css_set_lock);
if (!list_empty(&root->root_list)) {
list_del(&root->root_list);
ss->root = dst_root;
css->cgroup = dcgrp;
- spin_lock_bh(&css_set_lock);
+ spin_lock_irq(&css_set_lock);
hash_for_each(css_set_table, i, cset, hlist)
list_move_tail(&cset->e_cset_node[ss->id],
&dcgrp->e_csets[ss->id]);
- spin_unlock_bh(&css_set_lock);
+ spin_unlock_irq(&css_set_lock);
src_root->subsys_mask &= ~(1 << ssid);
scgrp->subtree_control &= ~(1 << ssid);
{
struct task_struct *p, *g;
- spin_lock_bh(&css_set_lock);
+ spin_lock_irq(&css_set_lock);
if (use_task_css_set_links)
goto out_unlock;
* entry won't be deleted though the process has exited.
* Do it while holding siglock so that we don't end up
* racing against cgroup_exit().
+ *
+ * Interrupts were already disabled while acquiring
+ * the css_set_lock, so we do not need to disable it
+ * again when acquiring the sighand->siglock here.
*/
- spin_lock_irq(&p->sighand->siglock);
+ spin_lock(&p->sighand->siglock);
if (!(p->flags & PF_EXITING)) {
struct css_set *cset = task_css_set(p);
list_add_tail(&p->cg_list, &cset->tasks);
get_css_set(cset);
}
- spin_unlock_irq(&p->sighand->siglock);
+ spin_unlock(&p->sighand->siglock);
} while_each_thread(g, p);
read_unlock(&tasklist_lock);
out_unlock:
- spin_unlock_bh(&css_set_lock);
+ spin_unlock_irq(&css_set_lock);
}
static void init_cgroup_housekeeping(struct cgroup *cgrp)
* Link the root cgroup in this hierarchy into all the css_set
* objects.
*/
- spin_lock_bh(&css_set_lock);
+ spin_lock_irq(&css_set_lock);
hash_for_each(css_set_table, i, cset, hlist) {
link_css_set(&tmp_links, cset, root_cgrp);
if (css_set_populated(cset))
cgroup_update_populated(root_cgrp, true);
}
- spin_unlock_bh(&css_set_lock);
+ spin_unlock_irq(&css_set_lock);
BUG_ON(!list_empty(&root_cgrp->self.children));
BUG_ON(atomic_read(&root->nr_cgrps) != 1);
char *path = NULL;
mutex_lock(&cgroup_mutex);
- spin_lock_bh(&css_set_lock);
+ spin_lock_irq(&css_set_lock);
root = idr_get_next(&cgroup_hierarchy_idr, &hierarchy_id);
path = buf;
}
- spin_unlock_bh(&css_set_lock);
+ spin_unlock_irq(&css_set_lock);
mutex_unlock(&cgroup_mutex);
return path;
}
* the new cgroup. There are no failure cases after here, so this
* is the commit point.
*/
- spin_lock_bh(&css_set_lock);
+ spin_lock_irq(&css_set_lock);
list_for_each_entry(cset, &tset->src_csets, mg_node) {
list_for_each_entry_safe(task, tmp_task, &cset->mg_tasks, cg_list) {
struct css_set *from_cset = task_css_set(task);
put_css_set_locked(from_cset);
}
}
- spin_unlock_bh(&css_set_lock);
+ spin_unlock_irq(&css_set_lock);
/*
* Migration is committed, all target tasks are now on dst_csets.
}
}
out_release_tset:
- spin_lock_bh(&css_set_lock);
+ spin_lock_irq(&css_set_lock);
list_splice_init(&tset->dst_csets, &tset->src_csets);
list_for_each_entry_safe(cset, tmp_cset, &tset->src_csets, mg_node) {
list_splice_tail_init(&cset->mg_tasks, &cset->tasks);
list_del_init(&cset->mg_node);
}
- spin_unlock_bh(&css_set_lock);
+ spin_unlock_irq(&css_set_lock);
return ret;
}
lockdep_assert_held(&cgroup_mutex);
- spin_lock_bh(&css_set_lock);
+ spin_lock_irq(&css_set_lock);
list_for_each_entry_safe(cset, tmp_cset, preloaded_csets, mg_preload_node) {
cset->mg_src_cgrp = NULL;
cset->mg_dst_cset = NULL;
list_del_init(&cset->mg_preload_node);
put_css_set_locked(cset);
}
- spin_unlock_bh(&css_set_lock);
+ spin_unlock_irq(&css_set_lock);
}
/**
lockdep_assert_held(&cgroup_mutex);
lockdep_assert_held(&css_set_lock);
+ /*
+ * If ->dead, @src_set is associated with one or more dead cgroups
+ * and doesn't contain any migratable tasks. Ignore it early so
+ * that the rest of migration path doesn't get confused by it.
+ */
+ if (src_cset->dead)
+ return;
+
src_cgrp = cset_cgroup_from_root(src_cset, dst_cgrp->root);
if (!list_empty(&src_cset->mg_preload_node))
* already PF_EXITING could be freed from underneath us unless we
* take an rcu_read_lock.
*/
- spin_lock_bh(&css_set_lock);
+ spin_lock_irq(&css_set_lock);
rcu_read_lock();
task = leader;
do {
break;
} while_each_thread(leader, task);
rcu_read_unlock();
- spin_unlock_bh(&css_set_lock);
+ spin_unlock_irq(&css_set_lock);
return cgroup_taskset_migrate(&tset, cgrp);
}
int ret;
/* look up all src csets */
- spin_lock_bh(&css_set_lock);
+ spin_lock_irq(&css_set_lock);
rcu_read_lock();
task = leader;
do {
break;
} while_each_thread(leader, task);
rcu_read_unlock();
- spin_unlock_bh(&css_set_lock);
+ spin_unlock_irq(&css_set_lock);
/* prepare dst csets and commit */
ret = cgroup_migrate_prepare_dst(dst_cgrp, &preloaded_csets);
struct cgroup *cgrp;
struct inode *inode;
- spin_lock_bh(&css_set_lock);
+ spin_lock_irq(&css_set_lock);
cgrp = task_cgroup_from_root(task, &cgrp_dfl_root);
- spin_unlock_bh(&css_set_lock);
+ spin_unlock_irq(&css_set_lock);
while (!cgroup_is_descendant(dst_cgrp, cgrp))
cgrp = cgroup_parent(cgrp);
size_t nbytes, loff_t off, bool threadgroup)
{
struct task_struct *tsk;
+ struct cgroup_subsys *ss;
struct cgroup *cgrp;
pid_t pid;
- int ret;
+ int ssid, ret;
if (kstrtoint(strstrip(buf), 0, &pid) || pid < 0)
return -EINVAL;
tsk = tsk->group_leader;
/*
- * Workqueue threads may acquire PF_NO_SETAFFINITY and become
- * trapped in a cpuset, or RT worker may be born in a cgroup
- * with no rt_runtime allocated. Just say no.
+ * kthreads may acquire PF_NO_SETAFFINITY during initialization.
+ * If userland migrates such a kthread to a non-root cgroup, it can
+ * become trapped in a cpuset, or RT kthread may be born in a
+ * cgroup with no rt_runtime allocated. Just say no.
*/
- if (tsk == kthreadd_task || (tsk->flags & PF_NO_SETAFFINITY)) {
+ if (tsk->no_cgroup_migration || (tsk->flags & PF_NO_SETAFFINITY)) {
ret = -EINVAL;
goto out_unlock_rcu;
}
rcu_read_unlock();
out_unlock_threadgroup:
percpu_up_write(&cgroup_threadgroup_rwsem);
+ for_each_subsys(ss, ssid)
+ if (ss->post_attach)
+ ss->post_attach();
cgroup_kn_unlock(of->kn);
return ret ?: nbytes;
}
if (root == &cgrp_dfl_root)
continue;
- spin_lock_bh(&css_set_lock);
+ spin_lock_irq(&css_set_lock);
from_cgrp = task_cgroup_from_root(from, root);
- spin_unlock_bh(&css_set_lock);
+ spin_unlock_irq(&css_set_lock);
retval = cgroup_attach_task(from_cgrp, tsk, false);
if (retval)
percpu_down_write(&cgroup_threadgroup_rwsem);
/* look up all csses currently attached to @cgrp's subtree */
- spin_lock_bh(&css_set_lock);
+ spin_lock_irq(&css_set_lock);
css_for_each_descendant_pre(css, cgroup_css(cgrp, NULL)) {
struct cgrp_cset_link *link;
cgroup_migrate_add_src(link->cset, cgrp,
&preloaded_csets);
}
- spin_unlock_bh(&css_set_lock);
+ spin_unlock_irq(&css_set_lock);
/* NULL dst indicates self on default hierarchy */
ret = cgroup_migrate_prepare_dst(NULL, &preloaded_csets);
if (ret)
goto out_finish;
- spin_lock_bh(&css_set_lock);
+ spin_lock_irq(&css_set_lock);
list_for_each_entry(src_cset, &preloaded_csets, mg_preload_node) {
struct task_struct *task, *ntask;
list_for_each_entry_safe(task, ntask, &src_cset->tasks, cg_list)
cgroup_taskset_add(task, &tset);
}
- spin_unlock_bh(&css_set_lock);
+ spin_unlock_irq(&css_set_lock);
ret = cgroup_taskset_migrate(&tset, cgrp);
out_finish:
int count = 0;
struct cgrp_cset_link *link;
- spin_lock_bh(&css_set_lock);
+ spin_lock_irq(&css_set_lock);
list_for_each_entry(link, &cgrp->cset_links, cset_link)
count += atomic_read(&link->cset->refcount);
- spin_unlock_bh(&css_set_lock);
+ spin_unlock_irq(&css_set_lock);
return count;
}
memset(it, 0, sizeof(*it));
- spin_lock_bh(&css_set_lock);
+ spin_lock_irq(&css_set_lock);
it->ss = css->ss;
css_task_iter_advance_css_set(it);
- spin_unlock_bh(&css_set_lock);
+ spin_unlock_irq(&css_set_lock);
}
/**
it->cur_task = NULL;
}
- spin_lock_bh(&css_set_lock);
+ spin_lock_irq(&css_set_lock);
if (it->task_pos) {
it->cur_task = list_entry(it->task_pos, struct task_struct,
css_task_iter_advance(it);
}
- spin_unlock_bh(&css_set_lock);
+ spin_unlock_irq(&css_set_lock);
return it->cur_task;
}
void css_task_iter_end(struct css_task_iter *it)
{
if (it->cur_cset) {
- spin_lock_bh(&css_set_lock);
+ spin_lock_irq(&css_set_lock);
list_del(&it->iters_node);
put_css_set_locked(it->cur_cset);
- spin_unlock_bh(&css_set_lock);
+ spin_unlock_irq(&css_set_lock);
}
if (it->cur_task)
mutex_lock(&cgroup_mutex);
/* all tasks in @from are being moved, all csets are source */
- spin_lock_bh(&css_set_lock);
+ spin_lock_irq(&css_set_lock);
list_for_each_entry(link, &from->cset_links, cset_link)
cgroup_migrate_add_src(link->cset, to, &preloaded_csets);
- spin_unlock_bh(&css_set_lock);
+ spin_unlock_irq(&css_set_lock);
ret = cgroup_migrate_prepare_dst(to, &preloaded_csets);
if (ret)
*/
do {
css_task_iter_start(&from->self, &it);
- task = css_task_iter_next(&it);
+
+ do {
+ task = css_task_iter_next(&it);
+ } while (task && (task->flags & PF_EXITING));
+
if (task)
get_task_struct(task);
css_task_iter_end(&it);
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);
memset(css, 0, sizeof(*css));
css->cgroup = cgrp;
css->ss = ss;
+ css->id = -1;
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);
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;
}
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 */
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);
+ }
}
/**
__releases(&cgroup_mutex) __acquires(&cgroup_mutex)
{
struct cgroup_subsys_state *css;
+ struct cgrp_cset_link *link;
int ssid;
lockdep_assert_held(&cgroup_mutex);
return -EBUSY;
/*
- * Mark @cgrp dead. This prevents further task migration and child
- * creation by disabling cgroup_lock_live_group().
+ * Mark @cgrp and the associated csets dead. The former prevents
+ * further task migration and child creation by disabling
+ * cgroup_lock_live_group(). The latter makes the csets ignored by
+ * the migration path.
*/
cgrp->self.flags &= ~CSS_ONLINE;
+ spin_lock_irq(&css_set_lock);
+ list_for_each_entry(link, &cgrp->cset_links, cset_link)
+ link->cset->dead = true;
+ spin_unlock_irq(&css_set_lock);
+
/* initiate massacre of all css's */
for_each_css(css, ssid, cgrp)
kill_css(css);
goto out;
mutex_lock(&cgroup_mutex);
- spin_lock_bh(&css_set_lock);
+ spin_lock_irq(&css_set_lock);
for_each_root(root) {
struct cgroup_subsys *ss;
retval = 0;
out_unlock:
- spin_unlock_bh(&css_set_lock);
+ spin_unlock_irq(&css_set_lock);
mutex_unlock(&cgroup_mutex);
kfree(buf);
out:
if (use_task_css_set_links) {
struct css_set *cset;
- spin_lock_bh(&css_set_lock);
+ spin_lock_irq(&css_set_lock);
cset = task_css_set(current);
if (list_empty(&child->cg_list)) {
get_css_set(cset);
css_set_move_task(child, NULL, cset, false);
}
- spin_unlock_bh(&css_set_lock);
+ spin_unlock_irq(&css_set_lock);
}
/*
cset = task_css_set(tsk);
if (!list_empty(&tsk->cg_list)) {
- spin_lock_bh(&css_set_lock);
+ spin_lock_irq(&css_set_lock);
css_set_move_task(tsk, cset, NULL, false);
- spin_unlock_bh(&css_set_lock);
+ spin_unlock_irq(&css_set_lock);
} else {
get_css_set(cset);
}
if (!name_buf)
return -ENOMEM;
- spin_lock_bh(&css_set_lock);
+ spin_lock_irq(&css_set_lock);
rcu_read_lock();
cset = rcu_dereference(current->cgroups);
list_for_each_entry(link, &cset->cgrp_links, cgrp_link) {
c->root->hierarchy_id, name_buf);
}
rcu_read_unlock();
- spin_unlock_bh(&css_set_lock);
+ spin_unlock_irq(&css_set_lock);
kfree(name_buf);
return 0;
}
struct cgroup_subsys_state *css = seq_css(seq);
struct cgrp_cset_link *link;
- spin_lock_bh(&css_set_lock);
+ spin_lock_irq(&css_set_lock);
list_for_each_entry(link, &css->cgroup->cset_links, cset_link) {
struct css_set *cset = link->cset;
struct task_struct *task;
overflow:
seq_puts(seq, " ...\n");
}
- spin_unlock_bh(&css_set_lock);
+ spin_unlock_irq(&css_set_lock);
return 0;
}
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