Commit 006cb992 authored by Paul Menage's avatar Paul Menage Committed by Linus Torvalds

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
......@@ -19,4 +19,8 @@ SUBSYS(cpuacct)
/* */
#ifdef CONFIG_CGROUP_DEBUG
SUBSYS(debug)
#endif
/* */
......@@ -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
......
......@@ -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/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,
};
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