root/kernel/cgroup_debug.c

DEFINITIONS

1. debug_create
2. debug_destroy
3. cgroup_refcount_read
4. taskcount_read
5. current_css_set_read
6. current_css_set_refcount_read
7. releasable_read
8. debug_populate

/*
 * kernel/cgroup_debug.c - Example cgroup subsystem that
 * exposes debug info
 *
 * Copyright (C) Google Inc, 2007
 *
 * Developed by Paul Menage (menage@google.com)
 *
 */

#include <linux/cgroup.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/rcupdate.h>

#include <asm/atomic.h>

static struct cgroup_subsys_state *debug_create(struct cgroup_subsys *ss,
                                                   struct cgroup *cont)
{
        struct cgroup_subsys_state *css = kzalloc(sizeof(*css), GFP_KERNEL);

        if (!css)
                return ERR_PTR(-ENOMEM);

        return css;
}

static void debug_destroy(struct cgroup_subsys *ss, struct cgroup *cont)
{
        kfree(cont->subsys[debug_subsys_id]);
}

static u64 cgroup_refcount_read(struct cgroup *cont, struct cftype *cft)
{
        return atomic_read(&cont->count);
}

static u64 taskcount_read(struct cgroup *cont, struct cftype *cft)
{
        u64 count;

        cgroup_lock();
        count = cgroup_task_count(cont);
        cgroup_unlock();
        return count;
}

static u64 current_css_set_read(struct cgroup *cont, struct cftype *cft)
{
        return (u64)(long)current->cgroups;
}

static u64 current_css_set_refcount_read(struct cgroup *cont,
                                           struct cftype *cft)
{
        u64 count;

        rcu_read_lock();
        count = atomic_read(&current->cgroups->ref.refcount);
        rcu_read_unlock();
        return count;
}

static u64 releasable_read(struct cgroup *cgrp, struct cftype *cft)
{
        return test_bit(CGRP_RELEASABLE, &cgrp->flags);
}

static struct cftype files[] =  {
        {
                .name = "cgroup_refcount",
                .read_u64 = cgroup_refcount_read,
        },
        {
                .name = "taskcount",
                .read_u64 = taskcount_read,
        },

        {
                .name = "current_css_set",
                .read_u64 = current_css_set_read,
        },

        {
                .name = "current_css_set_refcount",
                .read_u64 = current_css_set_refcount_read,
        },

        {
                .name = "releasable",
                .read_u64 = releasable_read,
        }
};

static int debug_populate(struct cgroup_subsys *ss, struct cgroup *cont)
{
        return cgroup_add_files(cont, ss, files, ARRAY_SIZE(files));
}

struct cgroup_subsys debug_subsys = {
        .name = "debug",
        .create = debug_create,
        .destroy = debug_destroy,
        .populate = debug_populate,
        .subsys_id = debug_subsys_id,
};