1 files changed, 153 insertions, 0 deletions

diff --git a/kernel/cgroup/debug.c b/kernel/cgroup/debug.c
new file mode 100644
index 000000000000..1c209aa43733
--- /dev/null
+++ b/kernel/cgroup/debug.c
@@ -0,0 +1,153 @@
+#include <linux/ctype.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+
+#include "cgroup-internal.h"
+
+static struct cgroup_subsys_state *
+debug_css_alloc(struct cgroup_subsys_state *parent_css)
+{
+        struct cgroup_subsys_state *css = kzalloc(sizeof(*css), GFP_KERNEL);
+
+        if (!css)
+                return ERR_PTR(-ENOMEM);
+
+        return css;
+}
+
+static void debug_css_free(struct cgroup_subsys_state *css)
+{
+        kfree(css);
+}
+
+/*
+ * debug_taskcount_read - return the number of tasks in a cgroup.
+ * @cgrp: the cgroup in question
+ */
+static u64 debug_taskcount_read(struct cgroup_subsys_state *css,
+                                struct cftype *cft)
+{
+        return cgroup_task_count(css->cgroup);
+}
+
+static u64 current_css_set_read(struct cgroup_subsys_state *css,
+                                struct cftype *cft)
+{
+        return (u64)(unsigned long)current->cgroups;
+}
+
+static u64 current_css_set_refcount_read(struct cgroup_subsys_state *css,
+                                         struct cftype *cft)
+{
+        u64 count;
+
+        rcu_read_lock();
+        count = refcount_read(&task_css_set(current)->refcount);
+        rcu_read_unlock();
+        return count;
+}
+
+static int current_css_set_cg_links_read(struct seq_file *seq, void *v)
+{
+        struct cgrp_cset_link *link;
+        struct css_set *cset;
+        char *name_buf;
+
+        name_buf = kmalloc(NAME_MAX + 1, GFP_KERNEL);
+        if (!name_buf)
+                return -ENOMEM;
+
+        spin_lock_irq(&css_set_lock);
+        rcu_read_lock();
+        cset = rcu_dereference(current->cgroups);
+        list_for_each_entry(link, &cset->cgrp_links, cgrp_link) {
+                struct cgroup *c = link->cgrp;
+
+                cgroup_name(c, name_buf, NAME_MAX + 1);
+                seq_printf(seq, "Root %d group %s\n",
+                           c->root->hierarchy_id, name_buf);
+        }
+        rcu_read_unlock();
+        spin_unlock_irq(&css_set_lock);
+        kfree(name_buf);
+        return 0;
+}
+
+#define MAX_TASKS_SHOWN_PER_CSS 25
+static int cgroup_css_links_read(struct seq_file *seq, void *v)
+{
+        struct cgroup_subsys_state *css = seq_css(seq);
+        struct cgrp_cset_link *link;
+
+        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;
+                int count = 0;
+
+                seq_printf(seq, "css_set %pK\n", cset);
+
+                list_for_each_entry(task, &cset->tasks, cg_list) {
+                        if (count++ > MAX_TASKS_SHOWN_PER_CSS)
+                                goto overflow;
+                        seq_printf(seq, "  task %d\n", task_pid_vnr(task));
+                }
+
+                list_for_each_entry(task, &cset->mg_tasks, cg_list) {
+                        if (count++ > MAX_TASKS_SHOWN_PER_CSS)
+                                goto overflow;
+                        seq_printf(seq, "  task %d\n", task_pid_vnr(task));
+                }
+                continue;
+        overflow:
+                seq_puts(seq, "  ...\n");
+        }
+        spin_unlock_irq(&css_set_lock);
+        return 0;
+}
+
+static u64 releasable_read(struct cgroup_subsys_state *css, struct cftype *cft)
+{
+        return (!cgroup_is_populated(css->cgroup) &&
+                !css_has_online_children(&css->cgroup->self));
+}
+
+static struct cftype debug_files[] =  {
+        {
+                .name = "taskcount",
+                .read_u64 = debug_taskcount_read,
+        },
+
+        {
+                .name = "current_css_set",
+                .read_u64 = current_css_set_read,
+        },
+
+        {
+                .name = "current_css_set_refcount",
+                .read_u64 = current_css_set_refcount_read,
+        },
+
+        {
+                .name = "current_css_set_cg_links",
+                .seq_show = current_css_set_cg_links_read,
+        },
+
+        {
+                .name = "cgroup_css_links",
+                .seq_show = cgroup_css_links_read,
+        },
+
+        {
+                .name = "releasable",
+                .read_u64 = releasable_read,
+        },
+
+        { }     /* terminate */
+};
+
+struct cgroup_subsys debug_cgrp_subsys = {
+        .css_alloc = debug_css_alloc,
+        .css_free = debug_css_free,
+        .legacy_cftypes = debug_files,
+};