This example subsystem exports debugging information as an aid to diagnosing refcount leaks, etc, in the cgroup framework. Signed-off-by: Paul Menage --- include/linux/cgroup_subsys.h | 4 + init/Kconfig | 10 ++ kernel/Makefile | 1 kernel/cgroup_debug.c | 97 +++++++++++++++++++++++++++++ 4 files changed, 112 insertions(+) diff -puN include/linux/cgroup_subsys.h~task-cgroupsv11-simple-task-cgroup-debug-info-subsystem include/linux/cgroup_subsys.h --- a/include/linux/cgroup_subsys.h~task-cgroupsv11-simple-task-cgroup-debug-info-subsystem +++ a/include/linux/cgroup_subsys.h @@ -19,4 +19,8 @@ SUBSYS(cpuacct) /* */ +#ifdef CONFIG_CGROUP_DEBUG +SUBSYS(debug) +#endif + /* */ diff -puN init/Kconfig~task-cgroupsv11-simple-task-cgroup-debug-info-subsystem init/Kconfig --- a/init/Kconfig~task-cgroupsv11-simple-task-cgroup-debug-info-subsystem +++ a/init/Kconfig @@ -282,6 +282,16 @@ 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 diff -puN kernel/Makefile~task-cgroupsv11-simple-task-cgroup-debug-info-subsystem kernel/Makefile --- a/kernel/Makefile~task-cgroupsv11-simple-task-cgroup-debug-info-subsystem +++ a/kernel/Makefile @@ -39,6 +39,7 @@ 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 diff -puN /dev/null kernel/cgroup_debug.c --- /dev/null +++ a/kernel/cgroup_debug.c @@ -0,0 +1,97 @@ +/* + * kernel/ccontainer_debug.c - Example cgroup subsystem that + * exposes debug info + * + * Copyright (C) Google Inc, 2007 + * + * Developed by Paul Menage (menage@google.com) + * + */ + +#include +#include +#include +#include + +#include + +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(¤t->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, +}; _ -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/