/* * kernel/cgroup_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(¤t->cgroups->ref.refcount); rcu_read_unlock(); return count; } static u64 releasable_read(struct cgroup *cgrp, struct cftype *cft) { return test_bit(CGRP_RELEASABLE, &cgrp->flags); } static struct cftype files[] = { { .name = "cgroup_refcount", .read_u64 = cgroup_refcount_read, }, { .name = "taskcount", .read_u64 = taskcount_read, }, { .name = "current_css_set", .read_u64 = current_css_set_read, }, { .name = "current_css_set_refcount", .read_u64 = current_css_set_refcount_read, }, { .name = "releasable", .read_u64 = releasable_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, };