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