dm raid1: fix error count
[linux-2.6.git] / kernel / cgroup_debug.c
1 /*
2  * kernel/cgroup_debug.c - Example cgroup subsystem that
3  * exposes debug info
4  *
5  * Copyright (C) Google Inc, 2007
6  *
7  * Developed by Paul Menage (menage@google.com)
8  *
9  */
10
11 #include <linux/cgroup.h>
12 #include <linux/fs.h>
13 #include <linux/slab.h>
14 #include <linux/rcupdate.h>
15
16 #include <asm/atomic.h>
17
18 static struct cgroup_subsys_state *debug_create(struct cgroup_subsys *ss,
19                                                    struct cgroup *cont)
20 {
21         struct cgroup_subsys_state *css = kzalloc(sizeof(*css), GFP_KERNEL);
22
23         if (!css)
24                 return ERR_PTR(-ENOMEM);
25
26         return css;
27 }
28
29 static void debug_destroy(struct cgroup_subsys *ss, struct cgroup *cont)
30 {
31         kfree(cont->subsys[debug_subsys_id]);
32 }
33
34 static u64 cgroup_refcount_read(struct cgroup *cont, struct cftype *cft)
35 {
36         return atomic_read(&cont->count);
37 }
38
39 static u64 taskcount_read(struct cgroup *cont, struct cftype *cft)
40 {
41         u64 count;
42
43         cgroup_lock();
44         count = cgroup_task_count(cont);
45         cgroup_unlock();
46         return count;
47 }
48
49 static u64 current_css_set_read(struct cgroup *cont, struct cftype *cft)
50 {
51         return (u64)(long)current->cgroups;
52 }
53
54 static u64 current_css_set_refcount_read(struct cgroup *cont,
55                                            struct cftype *cft)
56 {
57         u64 count;
58
59         rcu_read_lock();
60         count = atomic_read(&current->cgroups->refcount);
61         rcu_read_unlock();
62         return count;
63 }
64
65 static u64 releasable_read(struct cgroup *cgrp, struct cftype *cft)
66 {
67         return test_bit(CGRP_RELEASABLE, &cgrp->flags);
68 }
69
70 static struct cftype files[] =  {
71         {
72                 .name = "cgroup_refcount",
73                 .read_u64 = cgroup_refcount_read,
74         },
75         {
76                 .name = "taskcount",
77                 .read_u64 = taskcount_read,
78         },
79
80         {
81                 .name = "current_css_set",
82                 .read_u64 = current_css_set_read,
83         },
84
85         {
86                 .name = "current_css_set_refcount",
87                 .read_u64 = current_css_set_refcount_read,
88         },
89
90         {
91                 .name = "releasable",
92                 .read_u64 = releasable_read,
93         },
94 };
95
96 static int debug_populate(struct cgroup_subsys *ss, struct cgroup *cont)
97 {
98         return cgroup_add_files(cont, ss, files, ARRAY_SIZE(files));
99 }
100
101 struct cgroup_subsys debug_subsys = {
102         .name = "debug",
103         .create = debug_create,
104         .destroy = debug_destroy,
105         .populate = debug_populate,
106         .subsys_id = debug_subsys_id,
107 };