2 * kernel/cgroup_debug.c - Example cgroup subsystem that
5 * Copyright (C) Google Inc, 2007
7 * Developed by Paul Menage (menage@google.com)
11 #include <linux/cgroup.h>
13 #include <linux/slab.h>
14 #include <linux/rcupdate.h>
16 #include <asm/atomic.h>
18 static struct cgroup_subsys_state *debug_create(struct cgroup_subsys *ss,
21 struct cgroup_subsys_state *css = kzalloc(sizeof(*css), GFP_KERNEL);
24 return ERR_PTR(-ENOMEM);
29 static void debug_destroy(struct cgroup_subsys *ss, struct cgroup *cont)
31 kfree(cont->subsys[debug_subsys_id]);
34 static u64 cgroup_refcount_read(struct cgroup *cont, struct cftype *cft)
36 return atomic_read(&cont->count);
39 static u64 taskcount_read(struct cgroup *cont, struct cftype *cft)
43 count = cgroup_task_count(cont);
47 static u64 current_css_set_read(struct cgroup *cont, struct cftype *cft)
49 return (u64)(long)current->cgroups;
52 static u64 current_css_set_refcount_read(struct cgroup *cont,
58 count = atomic_read(¤t->cgroups->refcount);
63 static u64 releasable_read(struct cgroup *cgrp, struct cftype *cft)
65 return test_bit(CGRP_RELEASABLE, &cgrp->flags);
68 static struct cftype files[] = {
70 .name = "cgroup_refcount",
71 .read_u64 = cgroup_refcount_read,
75 .read_u64 = taskcount_read,
79 .name = "current_css_set",
80 .read_u64 = current_css_set_read,
84 .name = "current_css_set_refcount",
85 .read_u64 = current_css_set_refcount_read,
90 .read_u64 = releasable_read,
94 static int debug_populate(struct cgroup_subsys *ss, struct cgroup *cont)
96 return cgroup_add_files(cont, ss, files, ARRAY_SIZE(files));
99 struct cgroup_subsys debug_subsys = {
101 .create = debug_create,
102 .destroy = debug_destroy,
103 .populate = debug_populate,
104 .subsys_id = debug_subsys_id,