/* * 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->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,};