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Diffstat (limited to 'kernel/cgroup/cgroup.c')
-rw-r--r--kernel/cgroup/cgroup.c152
1 files changed, 144 insertions, 8 deletions
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 3f2b4bde0f9c..327f37c9fdfa 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -593,6 +593,39 @@ static void cgroup_get_live(struct cgroup *cgrp)
css_get(&cgrp->self);
}
+/**
+ * __cgroup_task_count - count the number of tasks in a cgroup. The caller
+ * is responsible for taking the css_set_lock.
+ * @cgrp: the cgroup in question
+ */
+int __cgroup_task_count(const struct cgroup *cgrp)
+{
+ int count = 0;
+ struct cgrp_cset_link *link;
+
+ lockdep_assert_held(&css_set_lock);
+
+ list_for_each_entry(link, &cgrp->cset_links, cset_link)
+ count += link->cset->nr_tasks;
+
+ return count;
+}
+
+/**
+ * cgroup_task_count - count the number of tasks in a cgroup.
+ * @cgrp: the cgroup in question
+ */
+int cgroup_task_count(const struct cgroup *cgrp)
+{
+ int count;
+
+ spin_lock_irq(&css_set_lock);
+ count = __cgroup_task_count(cgrp);
+ spin_unlock_irq(&css_set_lock);
+
+ return count;
+}
+
struct cgroup_subsys_state *of_css(struct kernfs_open_file *of)
{
struct cgroup *cgrp = of->kn->parent->priv;
@@ -783,6 +816,8 @@ static void cgroup_update_populated(struct cgroup *cgrp, bool populated)
break;
cgroup1_check_for_release(cgrp);
+ TRACE_CGROUP_PATH(notify_populated, cgrp,
+ cgroup_is_populated(cgrp));
cgroup_file_notify(&cgrp->events_file);
child = cgrp;
@@ -2402,8 +2437,15 @@ static int cgroup_migrate_execute(struct cgroup_mgctx *mgctx)
get_css_set(to_cset);
to_cset->nr_tasks++;
css_set_move_task(task, from_cset, to_cset, true);
- put_css_set_locked(from_cset);
from_cset->nr_tasks--;
+ /*
+ * If the source or destination cgroup is frozen,
+ * the task might require to change its state.
+ */
+ cgroup_freezer_migrate_task(task, from_cset->dfl_cgrp,
+ to_cset->dfl_cgrp);
+ put_css_set_locked(from_cset);
+
}
}
spin_unlock_irq(&css_set_lock);
@@ -2602,7 +2644,7 @@ int cgroup_migrate_prepare_dst(struct cgroup_mgctx *mgctx)
dst_cset = find_css_set(src_cset, src_cset->mg_dst_cgrp);
if (!dst_cset)
- goto err;
+ return -ENOMEM;
WARN_ON_ONCE(src_cset->mg_dst_cset || dst_cset->mg_dst_cset);
@@ -2634,9 +2676,6 @@ int cgroup_migrate_prepare_dst(struct cgroup_mgctx *mgctx)
}
return 0;
-err:
- cgroup_migrate_finish(mgctx);
- return -ENOMEM;
}
/**
@@ -3447,8 +3486,11 @@ static ssize_t cgroup_max_depth_write(struct kernfs_open_file *of,
static int cgroup_events_show(struct seq_file *seq, void *v)
{
- seq_printf(seq, "populated %d\n",
- cgroup_is_populated(seq_css(seq)->cgroup));
+ struct cgroup *cgrp = seq_css(seq)->cgroup;
+
+ seq_printf(seq, "populated %d\n", cgroup_is_populated(cgrp));
+ seq_printf(seq, "frozen %d\n", test_bit(CGRP_FROZEN, &cgrp->flags));
+
return 0;
}
@@ -3510,6 +3552,40 @@ static int cgroup_cpu_pressure_show(struct seq_file *seq, void *v)
}
#endif
+static int cgroup_freeze_show(struct seq_file *seq, void *v)
+{
+ struct cgroup *cgrp = seq_css(seq)->cgroup;
+
+ seq_printf(seq, "%d\n", cgrp->freezer.freeze);
+
+ return 0;
+}
+
+static ssize_t cgroup_freeze_write(struct kernfs_open_file *of,
+ char *buf, size_t nbytes, loff_t off)
+{
+ struct cgroup *cgrp;
+ ssize_t ret;
+ int freeze;
+
+ ret = kstrtoint(strstrip(buf), 0, &freeze);
+ if (ret)
+ return ret;
+
+ if (freeze < 0 || freeze > 1)
+ return -ERANGE;
+
+ cgrp = cgroup_kn_lock_live(of->kn, false);
+ if (!cgrp)
+ return -ENOENT;
+
+ cgroup_freeze(cgrp, freeze);
+
+ cgroup_kn_unlock(of->kn);
+
+ return nbytes;
+}
+
static int cgroup_file_open(struct kernfs_open_file *of)
{
struct cftype *cft = of->kn->priv;
@@ -4654,6 +4730,12 @@ static struct cftype cgroup_base_files[] = {
.seq_show = cgroup_stat_show,
},
{
+ .name = "cgroup.freeze",
+ .flags = CFTYPE_NOT_ON_ROOT,
+ .seq_show = cgroup_freeze_show,
+ .write = cgroup_freeze_write,
+ },
+ {
.name = "cpu.stat",
.flags = CFTYPE_NOT_ON_ROOT,
.seq_show = cpu_stat_show,
@@ -4781,9 +4863,11 @@ static void css_release_work_fn(struct work_struct *work)
if (cgroup_on_dfl(cgrp))
cgroup_rstat_flush(cgrp);
+ spin_lock_irq(&css_set_lock);
for (tcgrp = cgroup_parent(cgrp); tcgrp;
tcgrp = cgroup_parent(tcgrp))
tcgrp->nr_dying_descendants--;
+ spin_unlock_irq(&css_set_lock);
cgroup_idr_remove(&cgrp->root->cgroup_idr, cgrp->id);
cgrp->id = -1;
@@ -5001,12 +5085,31 @@ static struct cgroup *cgroup_create(struct cgroup *parent)
if (ret)
goto out_psi_free;
+ /*
+ * New cgroup inherits effective freeze counter, and
+ * if the parent has to be frozen, the child has too.
+ */
+ cgrp->freezer.e_freeze = parent->freezer.e_freeze;
+ if (cgrp->freezer.e_freeze)
+ set_bit(CGRP_FROZEN, &cgrp->flags);
+
+ spin_lock_irq(&css_set_lock);
for (tcgrp = cgrp; tcgrp; tcgrp = cgroup_parent(tcgrp)) {
cgrp->ancestor_ids[tcgrp->level] = tcgrp->id;
- if (tcgrp != cgrp)
+ if (tcgrp != cgrp) {
tcgrp->nr_descendants++;
+
+ /*
+ * If the new cgroup is frozen, all ancestor cgroups
+ * get a new frozen descendant, but their state can't
+ * change because of this.
+ */
+ if (cgrp->freezer.e_freeze)
+ tcgrp->freezer.nr_frozen_descendants++;
+ }
}
+ spin_unlock_irq(&css_set_lock);
if (notify_on_release(parent))
set_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
@@ -5291,10 +5394,18 @@ static int cgroup_destroy_locked(struct cgroup *cgrp)
if (parent && cgroup_is_threaded(cgrp))
parent->nr_threaded_children--;
+ spin_lock_irq(&css_set_lock);
for (tcgrp = cgroup_parent(cgrp); tcgrp; tcgrp = cgroup_parent(tcgrp)) {
tcgrp->nr_descendants--;
tcgrp->nr_dying_descendants++;
+ /*
+ * If the dying cgroup is frozen, decrease frozen descendants
+ * counters of ancestor cgroups.
+ */
+ if (test_bit(CGRP_FROZEN, &cgrp->flags))
+ tcgrp->freezer.nr_frozen_descendants--;
}
+ spin_unlock_irq(&css_set_lock);
cgroup1_check_for_release(parent);
@@ -5746,6 +5857,26 @@ void cgroup_post_fork(struct task_struct *child)
cset->nr_tasks++;
css_set_move_task(child, NULL, cset, false);
}
+
+ /*
+ * If the cgroup has to be frozen, the new task has too.
+ * Let's set the JOBCTL_TRAP_FREEZE jobctl bit to get
+ * the task into the frozen state.
+ */
+ if (unlikely(cgroup_task_freeze(child))) {
+ spin_lock(&child->sighand->siglock);
+ WARN_ON_ONCE(child->frozen);
+ child->jobctl |= JOBCTL_TRAP_FREEZE;
+ spin_unlock(&child->sighand->siglock);
+
+ /*
+ * Calling cgroup_update_frozen() isn't required here,
+ * because it will be called anyway a bit later
+ * from do_freezer_trap(). So we avoid cgroup's
+ * transient switch from the frozen state and back.
+ */
+ }
+
spin_unlock_irq(&css_set_lock);
}
@@ -5794,6 +5925,11 @@ void cgroup_exit(struct task_struct *tsk)
spin_lock_irq(&css_set_lock);
css_set_move_task(tsk, cset, NULL, false);
cset->nr_tasks--;
+
+ WARN_ON_ONCE(cgroup_task_frozen(tsk));
+ if (unlikely(cgroup_task_freeze(tsk)))
+ cgroup_update_frozen(task_dfl_cgroup(tsk));
+
spin_unlock_irq(&css_set_lock);
} else {
get_css_set(cset);