KVM: Timer event should not unconditionally unhalt vcpu.
[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         count = cgroup_task_count(cont);
44         return count;
45 }
46
47 static u64 current_css_set_read(struct cgroup *cont, struct cftype *cft)
48 {
49         return (u64)(long)current->cgroups;
50 }
51
52 static u64 current_css_set_refcount_read(struct cgroup *cont,
53                                            struct cftype *cft)
54 {
55         u64 count;
56
57         rcu_read_lock();
58         count = atomic_read(&current->cgroups->refcount);
59         rcu_read_unlock();
60         return count;
61 }
62
63 static u64 releasable_read(struct cgroup *cgrp, struct cftype *cft)
64 {
65         return test_bit(CGRP_RELEASABLE, &cgrp->flags);
66 }
67
68 static struct cftype files[] =  {
69         {
70                 .name = "cgroup_refcount",
71                 .read_u64 = cgroup_refcount_read,
72         },
73         {
74                 .name = "taskcount",
75                 .read_u64 = taskcount_read,
76         },
77
78         {
79                 .name = "current_css_set",
80                 .read_u64 = current_css_set_read,
81         },
82
83         {
84                 .name = "current_css_set_refcount",
85                 .read_u64 = current_css_set_refcount_read,
86         },
87
88         {
89                 .name = "releasable",
90                 .read_u64 = releasable_read,
91         },
92 };
93
94 static int debug_populate(struct cgroup_subsys *ss, struct cgroup *cont)
95 {
96         return cgroup_add_files(cont, ss, files, ARRAY_SIZE(files));
97 }
98
99 struct cgroup_subsys debug_subsys = {
100         .name = "debug",
101         .create = debug_create,
102         .destroy = debug_destroy,
103         .populate = debug_populate,
104         .subsys_id = debug_subsys_id,
105 };