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006cb992 PM |
1 | /* |
2 | * kernel/ccontainer_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(¤t->cgroups->ref.refcount); | |
61 | rcu_read_unlock(); | |
62 | return count; | |
63 | } | |
64 | ||
65 | static struct cftype files[] = { | |
66 | { | |
67 | .name = "cgroup_refcount", | |
f4c753b7 | 68 | .read_u64 = cgroup_refcount_read, |
006cb992 PM |
69 | }, |
70 | { | |
71 | .name = "taskcount", | |
f4c753b7 | 72 | .read_u64 = taskcount_read, |
006cb992 PM |
73 | }, |
74 | ||
75 | { | |
76 | .name = "current_css_set", | |
f4c753b7 | 77 | .read_u64 = current_css_set_read, |
006cb992 PM |
78 | }, |
79 | ||
80 | { | |
81 | .name = "current_css_set_refcount", | |
f4c753b7 | 82 | .read_u64 = current_css_set_refcount_read, |
006cb992 PM |
83 | }, |
84 | }; | |
85 | ||
86 | static int debug_populate(struct cgroup_subsys *ss, struct cgroup *cont) | |
87 | { | |
88 | return cgroup_add_files(cont, ss, files, ARRAY_SIZE(files)); | |
89 | } | |
90 | ||
91 | struct cgroup_subsys debug_subsys = { | |
92 | .name = "debug", | |
93 | .create = debug_create, | |
94 | .destroy = debug_destroy, | |
95 | .populate = debug_populate, | |
96 | .subsys_id = debug_subsys_id, | |
97 | }; |