From 006cb99200a38a8e3b0cbc1be48035a08921e601 Mon Sep 17 00:00:00 2001 From: Paul Menage Date: Thu, 18 Oct 2007 23:39:43 -0700 Subject: [PATCH] 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: Paul Menage Cc: Serge E. Hallyn Cc: "Eric W. Biederman" Cc: Dave Hansen Cc: Balbir Singh Cc: Paul Jackson Cc: Kirill Korotaev Cc: Herbert Poetzl Cc: Srivatsa Vaddagiri Cc: Cedric Le Goater Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/cgroup_subsys.h | 4 ++ init/Kconfig | 10 ++++ kernel/Makefile | 1 + kernel/cgroup_debug.c | 97 +++++++++++++++++++++++++++++++++++ 4 files changed, 112 insertions(+) create mode 100644 kernel/cgroup_debug.c diff --git a/include/linux/cgroup_subsys.h b/include/linux/cgroup_subsys.h index a568b8746f..cbadc3b5db 100644 --- a/include/linux/cgroup_subsys.h +++ b/include/linux/cgroup_subsys.h @@ -19,4 +19,8 @@ SUBSYS(cpuacct) /* */ +#ifdef CONFIG_CGROUP_DEBUG +SUBSYS(debug) +#endif + /* */ diff --git a/init/Kconfig b/init/Kconfig index b59a0a95a0..6687f805b3 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -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 diff --git a/kernel/Makefile b/kernel/Makefile index 48a7fae002..a50a6debe5 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -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 diff --git a/kernel/cgroup_debug.c b/kernel/cgroup_debug.c new file mode 100644 index 0000000000..37301e877c --- /dev/null +++ b/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, +}; -- 2.39.5