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Commit 006cb992 authored by Paul Menage's avatar Paul Menage Committed by Linus Torvalds
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Task Control Groups: simple task cgroup debug info subsystem 



This example subsystem exports debugging information as an aid to diagnosing
refcount leaks, etc, in the cgroup framework.

Signed-off-by: default avatarPaul Menage <menage@google.com>
Cc: Serge E. Hallyn <serue@us.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 62d0df64

include/linux/cgroup_subsys.h

+4 −0
Original line number Diff line number Diff line
@@ -19,4 +19,8 @@ SUBSYS(cpuacct) 


/* */



#ifdef CONFIG_CGROUP_DEBUG

SUBSYS(debug)

#endif



/* */

init/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -278,6 +278,16 @@ config CGROUPS 


	  Say N if unsure.



config CGROUP_DEBUG

	bool "Example debug cgroup subsystem"

	depends on CGROUPS

	help

	  This option enables a simple cgroup subsystem that

	  exports useful debugging information about the cgroups

	  framework



	  Say N if unsure



config CPUSETS

	bool "Cpuset support"

	depends on SMP && CGROUPS

kernel/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -37,6 +37,7 @@ obj-$(CONFIG_BSD_PROCESS_ACCT) += acct.o 
obj-$(CONFIG_KEXEC) += kexec.o

obj-$(CONFIG_COMPAT) += compat.o

obj-$(CONFIG_CGROUPS) += cgroup.o

obj-$(CONFIG_CGROUP_DEBUG) += cgroup_debug.o

obj-$(CONFIG_CPUSETS) += cpuset.o

obj-$(CONFIG_CGROUP_CPUACCT) += cpu_acct.o

obj-$(CONFIG_IKCONFIG) += configs.o

kernel/cgroup_debug.c

0 → 100644
+97 −0
Original line number Diff line number Diff line 
/*

 * kernel/ccontainer_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 struct cftype files[] =  {

	{

		.name = "cgroup_refcount",

		.read_uint = cgroup_refcount_read,

	},

	{

		.name = "taskcount",

		.read_uint = taskcount_read,

	},



	{

		.name = "current_css_set",

		.read_uint = current_css_set_read,

	},



	{

		.name = "current_css_set_refcount",

		.read_uint = current_css_set_refcount_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,

};