This example subsystem exports debugging information as an aid to diagnosing
refcount leaks, etc, in the container framework.
Signed-off-by: Paul Menage <[email protected]>
---
include/linux/container_subsys.h | 4 +
init/Kconfig | 10 ++++
kernel/Makefile | 1
kernel/container_debug.c | 97 +++++++++++++++++++++++++++++++++++++++
4 files changed, 112 insertions(+)
Index: container-2.6.22-rc6-mm1/include/linux/container_subsys.h
===================================================================
--- container-2.6.22-rc6-mm1.orig/include/linux/container_subsys.h
+++ container-2.6.22-rc6-mm1/include/linux/container_subsys.h
@@ -19,4 +19,8 @@ SUBSYS(cpuacct)
/* */
+#ifdef CONFIG_CONTAINER_DEBUG
+SUBSYS(debug)
+#endif
+
/* */
Index: container-2.6.22-rc6-mm1/init/Kconfig
===================================================================
--- container-2.6.22-rc6-mm1.orig/init/Kconfig
+++ container-2.6.22-rc6-mm1/init/Kconfig
@@ -303,6 +303,16 @@ config CONTAINERS
Say N if unsure.
+config CONTAINER_DEBUG
+ bool "Example debug container subsystem"
+ depends on CONTAINERS
+ help
+ This option enables a simple container subsystem that
+ exports useful debugging information about the containers
+ framework
+
+ Say N if unsure
+
config CPUSETS
bool "Cpuset support"
depends on SMP && CONTAINERS
Index: container-2.6.22-rc6-mm1/kernel/Makefile
===================================================================
--- container-2.6.22-rc6-mm1.orig/kernel/Makefile
+++ container-2.6.22-rc6-mm1/kernel/Makefile
@@ -38,6 +38,7 @@ obj-$(CONFIG_BSD_PROCESS_ACCT) += acct.o
obj-$(CONFIG_KEXEC) += kexec.o
obj-$(CONFIG_COMPAT) += compat.o
obj-$(CONFIG_CONTAINERS) += container.o
+obj-$(CONFIG_CONTAINER_DEBUG) += container_debug.o
obj-$(CONFIG_CPUSETS) += cpuset.o
obj-$(CONFIG_CONTAINER_CPUACCT) += cpu_acct.o
obj-$(CONFIG_IKCONFIG) += configs.o
Index: container-2.6.22-rc6-mm1/kernel/container_debug.c
===================================================================
--- /dev/null
+++ container-2.6.22-rc6-mm1/kernel/container_debug.c
@@ -0,0 +1,97 @@
+/*
+ * kernel/ccontainer_debug.c - Example container subsystem that
+ * exposes debug info
+ *
+ * Copyright (C) Google Inc, 2007
+ *
+ * Developed by Paul Menage ([email protected])
+ *
+ */
+
+#include <linux/container.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/rcupdate.h>
+
+#include <asm/atomic.h>
+
+static struct container_subsys_state *debug_create(struct container_subsys *ss,
+ struct container *cont)
+{
+ struct container_subsys_state *css = kzalloc(sizeof(*css), GFP_KERNEL);
+
+ if (!css)
+ return ERR_PTR(-ENOMEM);
+
+ return css;
+}
+
+static void debug_destroy(struct container_subsys *ss, struct container *cont)
+{
+ kfree(cont->subsys[debug_subsys_id]);
+}
+
+static u64 container_refcount_read(struct container *cont, struct cftype *cft)
+{
+ return atomic_read(&cont->count);
+}
+
+static u64 taskcount_read(struct container *cont, struct cftype *cft)
+{
+ u64 count;
+
+ container_lock();
+ count = container_task_count(cont);
+ container_unlock();
+ return count;
+}
+
+static u64 current_css_group_read(struct container *cont, struct cftype *cft)
+{
+ return (u64)(long)current->containers;
+}
+
+static u64 current_css_group_refcount_read(struct container *cont,
+ struct cftype *cft)
+{
+ u64 count;
+
+ rcu_read_lock();
+ count = atomic_read(¤t->containers->ref.refcount);
+ rcu_read_unlock();
+ return count;
+}
+
+static struct cftype files[] = {
+ {
+ .name = "container_refcount",
+ .read_uint = container_refcount_read,
+ },
+ {
+ .name = "taskcount",
+ .read_uint = taskcount_read,
+ },
+
+ {
+ .name = "current_css_group",
+ .read_uint = current_css_group_read,
+ },
+
+ {
+ .name = "current_css_group_refcount",
+ .read_uint = current_css_group_refcount_read,
+ },
+};
+
+static int debug_populate(struct container_subsys *ss, struct container *cont)
+{
+ return container_add_files(cont, ss, files, ARRAY_SIZE(files));
+}
+
+struct container_subsys debug_subsys = {
+ .name = "debug",
+ .create = debug_create,
+ .destroy = debug_destroy,
+ .populate = debug_populate,
+ .subsys_id = debug_subsys_id,
+};
--
-
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