/*
- * kernel/cgroup.c
- *
* Generic process-grouping system.
*
* Based originally on the cpuset system, extracted by Paul Menage
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/sort.h>
+#include <linux/kmod.h>
+#include <linux/delayacct.h>
+#include <linux/cgroupstats.h>
+
#include <asm/atomic.h>
+static DEFINE_MUTEX(cgroup_mutex);
+
/* Generate an array of cgroup subsystem pointers */
#define SUBSYS(_x) &_x ## _subsys,
/* Hierarchy-specific flags */
unsigned long flags;
+
+ /* The path to use for release notifications. No locking
+ * between setting and use - so if userspace updates this
+ * while child cgroups exist, you could miss a
+ * notification. We ensure that it's always a valid
+ * NUL-terminated string */
+ char release_agent_path[PATH_MAX];
};
/* bits in struct cgroup flags field */
enum {
- CONT_REMOVED,
+ /* Control Group is dead */
+ CGRP_REMOVED,
+ /* Control Group has previously had a child cgroup or a task,
+ * but no longer (only if CGRP_NOTIFY_ON_RELEASE is set) */
+ CGRP_RELEASABLE,
+ /* Control Group requires release notifications to userspace */
+ CGRP_NOTIFY_ON_RELEASE,
};
/* convenient tests for these bits */
-inline int cgroup_is_removed(const struct cgroup *cont)
+inline int cgroup_is_removed(const struct cgroup *cgrp)
{
- return test_bit(CONT_REMOVED, &cont->flags);
+ return test_bit(CGRP_REMOVED, &cgrp->flags);
}
/* bits in struct cgroupfs_root flags field */
ROOT_NOPREFIX, /* mounted subsystems have no named prefix */
};
+inline int cgroup_is_releasable(const struct cgroup *cgrp)
+{
+ const int bits =
+ (1 << CGRP_RELEASABLE) |
+ (1 << CGRP_NOTIFY_ON_RELEASE);
+ return (cgrp->flags & bits) == bits;
+}
+
+inline int notify_on_release(const struct cgroup *cgrp)
+{
+ return test_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
+}
+
/*
* for_each_subsys() allows you to iterate on each subsystem attached to
* an active hierarchy
#define for_each_root(_root) \
list_for_each_entry(_root, &roots, root_list)
+/* the list of cgroups eligible for automatic release. Protected by
+ * release_list_lock */
+static LIST_HEAD(release_list);
+static DEFINE_SPINLOCK(release_list_lock);
+static void cgroup_release_agent(struct work_struct *work);
+static DECLARE_WORK(release_agent_work, cgroup_release_agent);
+static void check_for_release(struct cgroup *cgrp);
+
/* Link structure for associating css_set objects with cgroups */
struct cg_cgroup_link {
/*
* List running through cg_cgroup_links associated with a
* cgroup, anchored on cgroup->css_sets
*/
- struct list_head cont_link_list;
+ struct list_head cgrp_link_list;
/*
* List running through cg_cgroup_links pointing at a
* single css_set object, anchored on css_set->cg_links
/*
* unlink a css_set from the list and free it
*/
-static void release_css_set(struct kref *k)
+static void unlink_css_set(struct css_set *cg)
{
- struct css_set *cg = container_of(k, struct css_set, ref);
- int i;
-
write_lock(&css_set_lock);
list_del(&cg->list);
css_set_count--;
link = list_entry(cg->cg_links.next,
struct cg_cgroup_link, cg_link_list);
list_del(&link->cg_link_list);
- list_del(&link->cont_link_list);
+ list_del(&link->cgrp_link_list);
kfree(link);
}
write_unlock(&css_set_lock);
- for (i = 0; i < CGROUP_SUBSYS_COUNT; i++)
- atomic_dec(&cg->subsys[i]->cgroup->count);
+}
+
+static void __release_css_set(struct kref *k, int taskexit)
+{
+ int i;
+ struct css_set *cg = container_of(k, struct css_set, ref);
+
+ unlink_css_set(cg);
+
+ rcu_read_lock();
+ for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
+ struct cgroup *cgrp = cg->subsys[i]->cgroup;
+ if (atomic_dec_and_test(&cgrp->count) &&
+ notify_on_release(cgrp)) {
+ if (taskexit)
+ set_bit(CGRP_RELEASABLE, &cgrp->flags);
+ check_for_release(cgrp);
+ }
+ }
+ rcu_read_unlock();
kfree(cg);
}
+static void release_css_set(struct kref *k)
+{
+ __release_css_set(k, 0);
+}
+
+static void release_css_set_taskexit(struct kref *k)
+{
+ __release_css_set(k, 1);
+}
+
/*
* refcounted get/put for css_set objects
*/
kref_put(&cg->ref, release_css_set);
}
+static inline void put_css_set_taskexit(struct css_set *cg)
+{
+ kref_put(&cg->ref, release_css_set_taskexit);
+}
+
/*
* find_existing_css_set() is a helper for
* find_css_set(), and checks to see whether an existing
* oldcg: the cgroup group that we're using before the cgroup
* transition
*
- * cont: the cgroup that we're moving into
+ * cgrp: the cgroup that we're moving into
*
* template: location in which to build the desired set of subsystem
* state objects for the new cgroup group
static struct css_set *find_existing_css_set(
struct css_set *oldcg,
- struct cgroup *cont,
+ struct cgroup *cgrp,
struct cgroup_subsys_state *template[])
{
int i;
- struct cgroupfs_root *root = cont->root;
+ struct cgroupfs_root *root = cgrp->root;
struct list_head *l = &init_css_set.list;
/* Built the set of subsystem state objects that we want to
/* Subsystem is in this hierarchy. So we want
* the subsystem state from the new
* cgroup */
- template[i] = cont->subsys[i];
+ template[i] = cgrp->subsys[i];
} else {
/* Subsystem is not in this hierarchy, so we
* don't want to change the subsystem state */
/*
* allocate_cg_links() allocates "count" cg_cgroup_link structures
- * and chains them on tmp through their cont_link_list fields. Returns 0 on
+ * and chains them on tmp through their cgrp_link_list fields. Returns 0 on
* success or a negative error
*/
while (!list_empty(tmp)) {
link = list_entry(tmp->next,
struct cg_cgroup_link,
- cont_link_list);
- list_del(&link->cont_link_list);
+ cgrp_link_list);
+ list_del(&link->cgrp_link_list);
kfree(link);
}
return -ENOMEM;
}
- list_add(&link->cont_link_list, tmp);
+ list_add(&link->cgrp_link_list, tmp);
}
return 0;
}
struct cg_cgroup_link *link;
link = list_entry(tmp->next,
struct cg_cgroup_link,
- cont_link_list);
- list_del(&link->cont_link_list);
+ cgrp_link_list);
+ list_del(&link->cgrp_link_list);
kfree(link);
}
}
*/
static struct css_set *find_css_set(
- struct css_set *oldcg, struct cgroup *cont)
+ struct css_set *oldcg, struct cgroup *cgrp)
{
struct css_set *res;
struct cgroup_subsys_state *template[CGROUP_SUBSYS_COUNT];
/* First see if we already have a cgroup group that matches
* the desired set */
write_lock(&css_set_lock);
- res = find_existing_css_set(oldcg, cont, template);
+ res = find_existing_css_set(oldcg, cgrp, template);
if (res)
get_css_set(res);
write_unlock(&css_set_lock);
write_lock(&css_set_lock);
/* Add reference counts and links from the new css_set. */
for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
- struct cgroup *cont = res->subsys[i]->cgroup;
+ struct cgroup *cgrp = res->subsys[i]->cgroup;
struct cgroup_subsys *ss = subsys[i];
- atomic_inc(&cont->count);
+ atomic_inc(&cgrp->count);
/*
* We want to add a link once per cgroup, so we
* only do it for the first subsystem in each
BUG_ON(list_empty(&tmp_cg_links));
link = list_entry(tmp_cg_links.next,
struct cg_cgroup_link,
- cont_link_list);
- list_del(&link->cont_link_list);
- list_add(&link->cont_link_list, &cont->css_sets);
+ cgrp_link_list);
+ list_del(&link->cgrp_link_list);
+ list_add(&link->cgrp_link_list, &cgrp->css_sets);
link->cg = res;
list_add(&link->cg_link_list, &res->cg_links);
}
if (list_empty(&rootnode.subsys_list)) {
link = list_entry(tmp_cg_links.next,
struct cg_cgroup_link,
- cont_link_list);
- list_del(&link->cont_link_list);
- list_add(&link->cont_link_list, &dummytop->css_sets);
+ cgrp_link_list);
+ list_del(&link->cgrp_link_list);
+ list_add(&link->cgrp_link_list, &dummytop->css_sets);
link->cg = res;
list_add(&link->cg_link_list, &res->cg_links);
}
* update of a tasks cgroup pointer by attach_task()
*/
-static DEFINE_MUTEX(cgroup_mutex);
-
/**
* cgroup_lock - lock out any changes to cgroup structures
*
static int cgroup_mkdir(struct inode *dir, struct dentry *dentry, int mode);
static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry);
-static int cgroup_populate_dir(struct cgroup *cont);
+static int cgroup_populate_dir(struct cgroup *cgrp);
static struct inode_operations cgroup_dir_inode_operations;
static struct file_operations proc_cgroupstats_operations;
{
/* is dentry a directory ? if so, kfree() associated cgroup */
if (S_ISDIR(inode->i_mode)) {
- struct cgroup *cont = dentry->d_fsdata;
- BUG_ON(!(cgroup_is_removed(cont)));
- kfree(cont);
+ struct cgroup *cgrp = dentry->d_fsdata;
+ BUG_ON(!(cgroup_is_removed(cgrp)));
+ /* It's possible for external users to be holding css
+ * reference counts on a cgroup; css_put() needs to
+ * be able to access the cgroup after decrementing
+ * the reference count in order to know if it needs to
+ * queue the cgroup to be handled by the release
+ * agent */
+ synchronize_rcu();
+ kfree(cgrp);
}
iput(inode);
}
unsigned long final_bits)
{
unsigned long added_bits, removed_bits;
- struct cgroup *cont = &root->top_cgroup;
+ struct cgroup *cgrp = &root->top_cgroup;
int i;
removed_bits = root->actual_subsys_bits & ~final_bits;
* any child cgroups exist. This is theoretically supportable
* but involves complex error handling, so it's being left until
* later */
- if (!list_empty(&cont->children))
+ if (!list_empty(&cgrp->children))
return -EBUSY;
/* Process each subsystem */
unsigned long bit = 1UL << i;
if (bit & added_bits) {
/* We're binding this subsystem to this hierarchy */
- BUG_ON(cont->subsys[i]);
+ BUG_ON(cgrp->subsys[i]);
BUG_ON(!dummytop->subsys[i]);
BUG_ON(dummytop->subsys[i]->cgroup != dummytop);
- cont->subsys[i] = dummytop->subsys[i];
- cont->subsys[i]->cgroup = cont;
+ cgrp->subsys[i] = dummytop->subsys[i];
+ cgrp->subsys[i]->cgroup = cgrp;
list_add(&ss->sibling, &root->subsys_list);
rcu_assign_pointer(ss->root, root);
if (ss->bind)
- ss->bind(ss, cont);
+ ss->bind(ss, cgrp);
} else if (bit & removed_bits) {
/* We're removing this subsystem */
- BUG_ON(cont->subsys[i] != dummytop->subsys[i]);
- BUG_ON(cont->subsys[i]->cgroup != cont);
+ BUG_ON(cgrp->subsys[i] != dummytop->subsys[i]);
+ BUG_ON(cgrp->subsys[i]->cgroup != cgrp);
if (ss->bind)
ss->bind(ss, dummytop);
dummytop->subsys[i]->cgroup = dummytop;
- cont->subsys[i] = NULL;
+ cgrp->subsys[i] = NULL;
rcu_assign_pointer(subsys[i]->root, &rootnode);
list_del(&ss->sibling);
} else if (bit & final_bits) {
/* Subsystem state should already exist */
- BUG_ON(!cont->subsys[i]);
+ BUG_ON(!cgrp->subsys[i]);
} else {
/* Subsystem state shouldn't exist */
- BUG_ON(cont->subsys[i]);
+ BUG_ON(cgrp->subsys[i]);
}
}
root->subsys_bits = root->actual_subsys_bits = final_bits;
seq_printf(seq, ",%s", ss->name);
if (test_bit(ROOT_NOPREFIX, &root->flags))
seq_puts(seq, ",noprefix");
+ if (strlen(root->release_agent_path))
+ seq_printf(seq, ",release_agent=%s", root->release_agent_path);
mutex_unlock(&cgroup_mutex);
return 0;
}
struct cgroup_sb_opts {
unsigned long subsys_bits;
unsigned long flags;
+ char *release_agent;
};
/* Convert a hierarchy specifier into a bitmask of subsystems and
opts->subsys_bits = 0;
opts->flags = 0;
+ opts->release_agent = NULL;
while ((token = strsep(&o, ",")) != NULL) {
if (!*token)
opts->subsys_bits = (1 << CGROUP_SUBSYS_COUNT) - 1;
} else if (!strcmp(token, "noprefix")) {
set_bit(ROOT_NOPREFIX, &opts->flags);
+ } else if (!strncmp(token, "release_agent=", 14)) {
+ /* Specifying two release agents is forbidden */
+ if (opts->release_agent)
+ return -EINVAL;
+ opts->release_agent = kzalloc(PATH_MAX, GFP_KERNEL);
+ if (!opts->release_agent)
+ return -ENOMEM;
+ strncpy(opts->release_agent, token + 14, PATH_MAX - 1);
+ opts->release_agent[PATH_MAX - 1] = 0;
} else {
struct cgroup_subsys *ss;
int i;
{
int ret = 0;
struct cgroupfs_root *root = sb->s_fs_info;
- struct cgroup *cont = &root->top_cgroup;
+ struct cgroup *cgrp = &root->top_cgroup;
struct cgroup_sb_opts opts;
- mutex_lock(&cont->dentry->d_inode->i_mutex);
+ mutex_lock(&cgrp->dentry->d_inode->i_mutex);
mutex_lock(&cgroup_mutex);
/* See what subsystems are wanted */
/* (re)populate subsystem files */
if (!ret)
- cgroup_populate_dir(cont);
+ cgroup_populate_dir(cgrp);
+ if (opts.release_agent)
+ strcpy(root->release_agent_path, opts.release_agent);
out_unlock:
+ if (opts.release_agent)
+ kfree(opts.release_agent);
mutex_unlock(&cgroup_mutex);
- mutex_unlock(&cont->dentry->d_inode->i_mutex);
+ mutex_unlock(&cgrp->dentry->d_inode->i_mutex);
return ret;
}
static void init_cgroup_root(struct cgroupfs_root *root)
{
- struct cgroup *cont = &root->top_cgroup;
+ struct cgroup *cgrp = &root->top_cgroup;
INIT_LIST_HEAD(&root->subsys_list);
INIT_LIST_HEAD(&root->root_list);
root->number_of_cgroups = 1;
- cont->root = root;
- cont->top_cgroup = cont;
- INIT_LIST_HEAD(&cont->sibling);
- INIT_LIST_HEAD(&cont->children);
- INIT_LIST_HEAD(&cont->css_sets);
+ cgrp->root = root;
+ cgrp->top_cgroup = cgrp;
+ INIT_LIST_HEAD(&cgrp->sibling);
+ INIT_LIST_HEAD(&cgrp->children);
+ INIT_LIST_HEAD(&cgrp->css_sets);
+ INIT_LIST_HEAD(&cgrp->release_list);
}
static int cgroup_test_super(struct super_block *sb, void *data)
/* First find the desired set of subsystems */
ret = parse_cgroupfs_options(data, &opts);
- if (ret)
+ if (ret) {
+ if (opts.release_agent)
+ kfree(opts.release_agent);
return ret;
+ }
root = kzalloc(sizeof(*root), GFP_KERNEL);
if (!root)
init_cgroup_root(root);
root->subsys_bits = opts.subsys_bits;
root->flags = opts.flags;
+ if (opts.release_agent) {
+ strcpy(root->release_agent_path, opts.release_agent);
+ kfree(opts.release_agent);
+ }
sb = sget(fs_type, cgroup_test_super, cgroup_set_super, root);
root = NULL;
} else {
/* New superblock */
- struct cgroup *cont = &root->top_cgroup;
+ struct cgroup *cgrp = &root->top_cgroup;
struct inode *inode;
BUG_ON(sb->s_root != NULL);
BUG_ON(list_empty(&tmp_cg_links));
link = list_entry(tmp_cg_links.next,
struct cg_cgroup_link,
- cont_link_list);
- list_del(&link->cont_link_list);
+ cgrp_link_list);
+ list_del(&link->cgrp_link_list);
link->cg = cg;
- list_add(&link->cont_link_list,
+ list_add(&link->cgrp_link_list,
&root->top_cgroup.css_sets);
list_add(&link->cg_link_list, &cg->cg_links);
l = l->next;
free_cg_links(&tmp_cg_links);
- BUG_ON(!list_empty(&cont->sibling));
- BUG_ON(!list_empty(&cont->children));
+ BUG_ON(!list_empty(&cgrp->sibling));
+ BUG_ON(!list_empty(&cgrp->children));
BUG_ON(root->number_of_cgroups != 1);
- cgroup_populate_dir(cont);
+ cgroup_populate_dir(cgrp);
mutex_unlock(&inode->i_mutex);
mutex_unlock(&cgroup_mutex);
}
static void cgroup_kill_sb(struct super_block *sb) {
struct cgroupfs_root *root = sb->s_fs_info;
- struct cgroup *cont = &root->top_cgroup;
+ struct cgroup *cgrp = &root->top_cgroup;
int ret;
BUG_ON(!root);
BUG_ON(root->number_of_cgroups != 1);
- BUG_ON(!list_empty(&cont->children));
- BUG_ON(!list_empty(&cont->sibling));
+ BUG_ON(!list_empty(&cgrp->children));
+ BUG_ON(!list_empty(&cgrp->sibling));
mutex_lock(&cgroup_mutex);
* root cgroup
*/
write_lock(&css_set_lock);
- while (!list_empty(&cont->css_sets)) {
+ while (!list_empty(&cgrp->css_sets)) {
struct cg_cgroup_link *link;
- link = list_entry(cont->css_sets.next,
- struct cg_cgroup_link, cont_link_list);
+ link = list_entry(cgrp->css_sets.next,
+ struct cg_cgroup_link, cgrp_link_list);
list_del(&link->cg_link_list);
- list_del(&link->cont_link_list);
+ list_del(&link->cgrp_link_list);
kfree(link);
}
write_unlock(&css_set_lock);
.kill_sb = cgroup_kill_sb,
};
-static inline struct cgroup *__d_cont(struct dentry *dentry)
+static inline struct cgroup *__d_cgrp(struct dentry *dentry)
{
return dentry->d_fsdata;
}
* Called with cgroup_mutex held. Writes path of cgroup into buf.
* Returns 0 on success, -errno on error.
*/
-int cgroup_path(const struct cgroup *cont, char *buf, int buflen)
+int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen)
{
char *start;
- if (cont == dummytop) {
+ if (cgrp == dummytop) {
/*
* Inactive subsystems have no dentry for their root
* cgroup
*--start = '\0';
for (;;) {
- int len = cont->dentry->d_name.len;
+ int len = cgrp->dentry->d_name.len;
if ((start -= len) < buf)
return -ENAMETOOLONG;
- memcpy(start, cont->dentry->d_name.name, len);
- cont = cont->parent;
- if (!cont)
+ memcpy(start, cgrp->dentry->d_name.name, len);
+ cgrp = cgrp->parent;
+ if (!cgrp)
break;
- if (!cont->parent)
+ if (!cgrp->parent)
continue;
if (--start < buf)
return -ENAMETOOLONG;
* its subsystem id.
*/
-static void get_first_subsys(const struct cgroup *cont,
+static void get_first_subsys(const struct cgroup *cgrp,
struct cgroup_subsys_state **css, int *subsys_id)
{
- const struct cgroupfs_root *root = cont->root;
+ const struct cgroupfs_root *root = cgrp->root;
const struct cgroup_subsys *test_ss;
BUG_ON(list_empty(&root->subsys_list));
test_ss = list_entry(root->subsys_list.next,
struct cgroup_subsys, sibling);
if (css) {
- *css = cont->subsys[test_ss->subsys_id];
+ *css = cgrp->subsys[test_ss->subsys_id];
BUG_ON(!*css);
}
if (subsys_id)
}
/*
- * Attach task 'tsk' to cgroup 'cont'
+ * Attach task 'tsk' to cgroup 'cgrp'
*
* Call holding cgroup_mutex. May take task_lock of
* the task 'pid' during call.
*/
-static int attach_task(struct cgroup *cont, struct task_struct *tsk)
+static int attach_task(struct cgroup *cgrp, struct task_struct *tsk)
{
int retval = 0;
struct cgroup_subsys *ss;
- struct cgroup *oldcont;
+ struct cgroup *oldcgrp;
struct css_set *cg = tsk->cgroups;
struct css_set *newcg;
- struct cgroupfs_root *root = cont->root;
+ struct cgroupfs_root *root = cgrp->root;
int subsys_id;
- get_first_subsys(cont, NULL, &subsys_id);
+ get_first_subsys(cgrp, NULL, &subsys_id);
/* Nothing to do if the task is already in that cgroup */
- oldcont = task_cgroup(tsk, subsys_id);
- if (cont == oldcont)
+ oldcgrp = task_cgroup(tsk, subsys_id);
+ if (cgrp == oldcgrp)
return 0;
for_each_subsys(root, ss) {
if (ss->can_attach) {
- retval = ss->can_attach(ss, cont, tsk);
+ retval = ss->can_attach(ss, cgrp, tsk);
if (retval) {
return retval;
}
* Locate or allocate a new css_set for this task,
* based on its final set of cgroups
*/
- newcg = find_css_set(cg, cont);
+ newcg = find_css_set(cg, cgrp);
if (!newcg) {
return -ENOMEM;
}
for_each_subsys(root, ss) {
if (ss->attach) {
- ss->attach(ss, cont, oldcont, tsk);
+ ss->attach(ss, cgrp, oldcgrp, tsk);
}
}
-
+ set_bit(CGRP_RELEASABLE, &oldcgrp->flags);
synchronize_rcu();
put_css_set(cg);
return 0;
}
/*
- * Attach task with pid 'pid' to cgroup 'cont'. Call with
+ * Attach task with pid 'pid' to cgroup 'cgrp'. Call with
* cgroup_mutex, may take task_lock of task
*/
-static int attach_task_by_pid(struct cgroup *cont, char *pidbuf)
+static int attach_task_by_pid(struct cgroup *cgrp, char *pidbuf)
{
pid_t pid;
struct task_struct *tsk;
get_task_struct(tsk);
}
- ret = attach_task(cont, tsk);
+ ret = attach_task(cgrp, tsk);
put_task_struct(tsk);
return ret;
}
FILE_ROOT,
FILE_DIR,
FILE_TASKLIST,
+ FILE_NOTIFY_ON_RELEASE,
+ FILE_RELEASABLE,
+ FILE_RELEASE_AGENT,
};
-static ssize_t cgroup_write_uint(struct cgroup *cont, struct cftype *cft,
+static ssize_t cgroup_write_uint(struct cgroup *cgrp, struct cftype *cft,
struct file *file,
const char __user *userbuf,
size_t nbytes, loff_t *unused_ppos)
return -EINVAL;
/* Pass to subsystem */
- retval = cft->write_uint(cont, cft, val);
+ retval = cft->write_uint(cgrp, cft, val);
if (!retval)
retval = nbytes;
return retval;
}
-static ssize_t cgroup_common_file_write(struct cgroup *cont,
+static ssize_t cgroup_common_file_write(struct cgroup *cgrp,
struct cftype *cft,
struct file *file,
const char __user *userbuf,
mutex_lock(&cgroup_mutex);
- if (cgroup_is_removed(cont)) {
+ if (cgroup_is_removed(cgrp)) {
retval = -ENODEV;
goto out2;
}
switch (type) {
case FILE_TASKLIST:
- retval = attach_task_by_pid(cont, buffer);
+ retval = attach_task_by_pid(cgrp, buffer);
+ break;
+ case FILE_NOTIFY_ON_RELEASE:
+ clear_bit(CGRP_RELEASABLE, &cgrp->flags);
+ if (simple_strtoul(buffer, NULL, 10) != 0)
+ set_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
+ else
+ clear_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
+ break;
+ case FILE_RELEASE_AGENT:
+ {
+ struct cgroupfs_root *root = cgrp->root;
+ /* Strip trailing newline */
+ if (nbytes && (buffer[nbytes-1] == '\n')) {
+ buffer[nbytes-1] = 0;
+ }
+ if (nbytes < sizeof(root->release_agent_path)) {
+ /* We never write anything other than '\0'
+ * into the last char of release_agent_path,
+ * so it always remains a NUL-terminated
+ * string */
+ strncpy(root->release_agent_path, buffer, nbytes);
+ root->release_agent_path[nbytes] = 0;
+ } else {
+ retval = -ENOSPC;
+ }
break;
+ }
default:
retval = -EINVAL;
goto out2;
size_t nbytes, loff_t *ppos)
{
struct cftype *cft = __d_cft(file->f_dentry);
- struct cgroup *cont = __d_cont(file->f_dentry->d_parent);
+ struct cgroup *cgrp = __d_cgrp(file->f_dentry->d_parent);
if (!cft)
return -ENODEV;
if (cft->write)
- return cft->write(cont, cft, file, buf, nbytes, ppos);
+ return cft->write(cgrp, cft, file, buf, nbytes, ppos);
if (cft->write_uint)
- return cgroup_write_uint(cont, cft, file, buf, nbytes, ppos);
+ return cgroup_write_uint(cgrp, cft, file, buf, nbytes, ppos);
return -EINVAL;
}
-static ssize_t cgroup_read_uint(struct cgroup *cont, struct cftype *cft,
+static ssize_t cgroup_read_uint(struct cgroup *cgrp, struct cftype *cft,
struct file *file,
char __user *buf, size_t nbytes,
loff_t *ppos)
{
char tmp[64];
- u64 val = cft->read_uint(cont, cft);
+ u64 val = cft->read_uint(cgrp, cft);
int len = sprintf(tmp, "%llu\n", (unsigned long long) val);
return simple_read_from_buffer(buf, nbytes, ppos, tmp, len);
}
+static ssize_t cgroup_common_file_read(struct cgroup *cgrp,
+ struct cftype *cft,
+ struct file *file,
+ char __user *buf,
+ size_t nbytes, loff_t *ppos)
+{
+ enum cgroup_filetype type = cft->private;
+ char *page;
+ ssize_t retval = 0;
+ char *s;
+
+ if (!(page = (char *)__get_free_page(GFP_KERNEL)))
+ return -ENOMEM;
+
+ s = page;
+
+ switch (type) {
+ case FILE_RELEASE_AGENT:
+ {
+ struct cgroupfs_root *root;
+ size_t n;
+ mutex_lock(&cgroup_mutex);
+ root = cgrp->root;
+ n = strnlen(root->release_agent_path,
+ sizeof(root->release_agent_path));
+ n = min(n, (size_t) PAGE_SIZE);
+ strncpy(s, root->release_agent_path, n);
+ mutex_unlock(&cgroup_mutex);
+ s += n;
+ break;
+ }
+ default:
+ retval = -EINVAL;
+ goto out;
+ }
+ *s++ = '\n';
+
+ retval = simple_read_from_buffer(buf, nbytes, ppos, page, s - page);
+out:
+ free_page((unsigned long)page);
+ return retval;
+}
+
static ssize_t cgroup_file_read(struct file *file, char __user *buf,
size_t nbytes, loff_t *ppos)
{
struct cftype *cft = __d_cft(file->f_dentry);
- struct cgroup *cont = __d_cont(file->f_dentry->d_parent);
+ struct cgroup *cgrp = __d_cgrp(file->f_dentry->d_parent);
if (!cft)
return -ENODEV;
if (cft->read)
- return cft->read(cont, cft, file, buf, nbytes, ppos);
+ return cft->read(cgrp, cft, file, buf, nbytes, ppos);
if (cft->read_uint)
- return cgroup_read_uint(cont, cft, file, buf, nbytes, ppos);
+ return cgroup_read_uint(cgrp, cft, file, buf, nbytes, ppos);
return -EINVAL;
}
/*
* cgroup_create_dir - create a directory for an object.
- * cont: the cgroup we create the directory for.
+ * cgrp: the cgroup we create the directory for.
* It must have a valid ->parent field
* And we are going to fill its ->dentry field.
- * dentry: dentry of the new container
+ * dentry: dentry of the new cgroup
* mode: mode to set on new directory.
*/
-static int cgroup_create_dir(struct cgroup *cont, struct dentry *dentry,
+static int cgroup_create_dir(struct cgroup *cgrp, struct dentry *dentry,
int mode)
{
struct dentry *parent;
int error = 0;
- parent = cont->parent->dentry;
- error = cgroup_create_file(dentry, S_IFDIR | mode, cont->root->sb);
+ parent = cgrp->parent->dentry;
+ error = cgroup_create_file(dentry, S_IFDIR | mode, cgrp->root->sb);
if (!error) {
- dentry->d_fsdata = cont;
+ dentry->d_fsdata = cgrp;
inc_nlink(parent->d_inode);
- cont->dentry = dentry;
+ cgrp->dentry = dentry;
dget(dentry);
}
dput(dentry);
return error;
}
-int cgroup_add_file(struct cgroup *cont,
+int cgroup_add_file(struct cgroup *cgrp,
struct cgroup_subsys *subsys,
const struct cftype *cft)
{
- struct dentry *dir = cont->dentry;
+ struct dentry *dir = cgrp->dentry;
struct dentry *dentry;
int error;
char name[MAX_CGROUP_TYPE_NAMELEN + MAX_CFTYPE_NAME + 2] = { 0 };
- if (subsys && !test_bit(ROOT_NOPREFIX, &cont->root->flags)) {
+ if (subsys && !test_bit(ROOT_NOPREFIX, &cgrp->root->flags)) {
strcpy(name, subsys->name);
strcat(name, ".");
}
dentry = lookup_one_len(name, dir, strlen(name));
if (!IS_ERR(dentry)) {
error = cgroup_create_file(dentry, 0644 | S_IFREG,
- cont->root->sb);
+ cgrp->root->sb);
if (!error)
dentry->d_fsdata = (void *)cft;
dput(dentry);
return error;
}
-int cgroup_add_files(struct cgroup *cont,
+int cgroup_add_files(struct cgroup *cgrp,
struct cgroup_subsys *subsys,
const struct cftype cft[],
int count)
{
int i, err;
for (i = 0; i < count; i++) {
- err = cgroup_add_file(cont, subsys, &cft[i]);
+ err = cgroup_add_file(cgrp, subsys, &cft[i]);
if (err)
return err;
}
/* Count the number of tasks in a cgroup. */
-int cgroup_task_count(const struct cgroup *cont)
+int cgroup_task_count(const struct cgroup *cgrp)
{
int count = 0;
struct list_head *l;
read_lock(&css_set_lock);
- l = cont->css_sets.next;
- while (l != &cont->css_sets) {
+ l = cgrp->css_sets.next;
+ while (l != &cgrp->css_sets) {
struct cg_cgroup_link *link =
- list_entry(l, struct cg_cgroup_link, cont_link_list);
+ list_entry(l, struct cg_cgroup_link, cgrp_link_list);
count += atomic_read(&link->cg->ref.refcount);
l = l->next;
}
* Advance a list_head iterator. The iterator should be positioned at
* the start of a css_set
*/
-static void cgroup_advance_iter(struct cgroup *cont,
+static void cgroup_advance_iter(struct cgroup *cgrp,
struct cgroup_iter *it)
{
struct list_head *l = it->cg_link;
/* Advance to the next non-empty css_set */
do {
l = l->next;
- if (l == &cont->css_sets) {
+ if (l == &cgrp->css_sets) {
it->cg_link = NULL;
return;
}
- link = list_entry(l, struct cg_cgroup_link, cont_link_list);
+ link = list_entry(l, struct cg_cgroup_link, cgrp_link_list);
cg = link->cg;
} while (list_empty(&cg->tasks));
it->cg_link = l;
it->task = cg->tasks.next;
}
-void cgroup_iter_start(struct cgroup *cont, struct cgroup_iter *it)
+void cgroup_iter_start(struct cgroup *cgrp, struct cgroup_iter *it)
{
/*
* The first time anyone tries to iterate across a cgroup,
write_unlock(&css_set_lock);
}
read_lock(&css_set_lock);
- it->cg_link = &cont->css_sets;
- cgroup_advance_iter(cont, it);
+ it->cg_link = &cgrp->css_sets;
+ cgroup_advance_iter(cgrp, it);
}
-struct task_struct *cgroup_iter_next(struct cgroup *cont,
+struct task_struct *cgroup_iter_next(struct cgroup *cgrp,
struct cgroup_iter *it)
{
struct task_struct *res;
if (l == &res->cgroups->tasks) {
/* We reached the end of this task list - move on to
* the next cg_cgroup_link */
- cgroup_advance_iter(cont, it);
+ cgroup_advance_iter(cgrp, it);
} else {
it->task = l;
}
return res;
}
-void cgroup_iter_end(struct cgroup *cont, struct cgroup_iter *it)
+void cgroup_iter_end(struct cgroup *cgrp, struct cgroup_iter *it)
{
read_unlock(&css_set_lock);
}
/*
* Load into 'pidarray' up to 'npids' of the tasks using cgroup
- * 'cont'. Return actual number of pids loaded. No need to
+ * 'cgrp'. Return actual number of pids loaded. No need to
* task_lock(p) when reading out p->cgroup, since we're in an RCU
* read section, so the css_set can't go away, and is
* immutable after creation.
*/
-static int pid_array_load(pid_t *pidarray, int npids, struct cgroup *cont)
+static int pid_array_load(pid_t *pidarray, int npids, struct cgroup *cgrp)
{
int n = 0;
struct cgroup_iter it;
struct task_struct *tsk;
- cgroup_iter_start(cont, &it);
- while ((tsk = cgroup_iter_next(cont, &it))) {
+ cgroup_iter_start(cgrp, &it);
+ while ((tsk = cgroup_iter_next(cgrp, &it))) {
if (unlikely(n == npids))
break;
- pidarray[n++] = pid_nr(task_pid(tsk));
+ pidarray[n++] = task_pid_nr(tsk);
}
- cgroup_iter_end(cont, &it);
+ cgroup_iter_end(cgrp, &it);
return n;
}
+/**
+ * Build and fill cgroupstats so that taskstats can export it to user
+ * space.
+ *
+ * @stats: cgroupstats to fill information into
+ * @dentry: A dentry entry belonging to the cgroup for which stats have
+ * been requested.
+ */
+int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry)
+{
+ int ret = -EINVAL;
+ struct cgroup *cgrp;
+ struct cgroup_iter it;
+ struct task_struct *tsk;
+ /*
+ * Validate dentry by checking the superblock operations
+ */
+ if (dentry->d_sb->s_op != &cgroup_ops)
+ goto err;
+
+ ret = 0;
+ cgrp = dentry->d_fsdata;
+ rcu_read_lock();
+
+ cgroup_iter_start(cgrp, &it);
+ while ((tsk = cgroup_iter_next(cgrp, &it))) {
+ switch (tsk->state) {
+ case TASK_RUNNING:
+ stats->nr_running++;
+ break;
+ case TASK_INTERRUPTIBLE:
+ stats->nr_sleeping++;
+ break;
+ case TASK_UNINTERRUPTIBLE:
+ stats->nr_uninterruptible++;
+ break;
+ case TASK_STOPPED:
+ stats->nr_stopped++;
+ break;
+ default:
+ if (delayacct_is_task_waiting_on_io(tsk))
+ stats->nr_io_wait++;
+ break;
+ }
+ }
+ cgroup_iter_end(cgrp, &it);
+
+ rcu_read_unlock();
+err:
+ return ret;
+}
+
static int cmppid(const void *a, const void *b)
{
return *(pid_t *)a - *(pid_t *)b;
*/
static int cgroup_tasks_open(struct inode *unused, struct file *file)
{
- struct cgroup *cont = __d_cont(file->f_dentry->d_parent);
+ struct cgroup *cgrp = __d_cgrp(file->f_dentry->d_parent);
struct ctr_struct *ctr;
pid_t *pidarray;
int npids;
* caller from the case that the additional cgroup users didn't
* show up until sometime later on.
*/
- npids = cgroup_task_count(cont);
+ npids = cgroup_task_count(cgrp);
if (npids) {
pidarray = kmalloc(npids * sizeof(pid_t), GFP_KERNEL);
if (!pidarray)
goto err1;
- npids = pid_array_load(pidarray, npids, cont);
+ npids = pid_array_load(pidarray, npids, cgrp);
sort(pidarray, npids, sizeof(pid_t), cmppid, NULL);
/* Call pid_array_to_buf() twice, first just to get bufsz */
return -ENOMEM;
}
-static ssize_t cgroup_tasks_read(struct cgroup *cont,
+static ssize_t cgroup_tasks_read(struct cgroup *cgrp,
struct cftype *cft,
struct file *file, char __user *buf,
size_t nbytes, loff_t *ppos)
return 0;
}
+static u64 cgroup_read_notify_on_release(struct cgroup *cgrp,
+ struct cftype *cft)
+{
+ return notify_on_release(cgrp);
+}
+
+static u64 cgroup_read_releasable(struct cgroup *cgrp, struct cftype *cft)
+{
+ return test_bit(CGRP_RELEASABLE, &cgrp->flags);
+}
+
/*
* for the common functions, 'private' gives the type of file
*/
-static struct cftype cft_tasks = {
- .name = "tasks",
- .open = cgroup_tasks_open,
- .read = cgroup_tasks_read,
+static struct cftype files[] = {
+ {
+ .name = "tasks",
+ .open = cgroup_tasks_open,
+ .read = cgroup_tasks_read,
+ .write = cgroup_common_file_write,
+ .release = cgroup_tasks_release,
+ .private = FILE_TASKLIST,
+ },
+
+ {
+ .name = "notify_on_release",
+ .read_uint = cgroup_read_notify_on_release,
+ .write = cgroup_common_file_write,
+ .private = FILE_NOTIFY_ON_RELEASE,
+ },
+
+ {
+ .name = "releasable",
+ .read_uint = cgroup_read_releasable,
+ .private = FILE_RELEASABLE,
+ }
+};
+
+static struct cftype cft_release_agent = {
+ .name = "release_agent",
+ .read = cgroup_common_file_read,
.write = cgroup_common_file_write,
- .release = cgroup_tasks_release,
- .private = FILE_TASKLIST,
+ .private = FILE_RELEASE_AGENT,
};
-static int cgroup_populate_dir(struct cgroup *cont)
+static int cgroup_populate_dir(struct cgroup *cgrp)
{
int err;
struct cgroup_subsys *ss;
/* First clear out any existing files */
- cgroup_clear_directory(cont->dentry);
+ cgroup_clear_directory(cgrp->dentry);
- err = cgroup_add_file(cont, NULL, &cft_tasks);
+ err = cgroup_add_files(cgrp, NULL, files, ARRAY_SIZE(files));
if (err < 0)
return err;
- for_each_subsys(cont->root, ss) {
- if (ss->populate && (err = ss->populate(ss, cont)) < 0)
+ if (cgrp == cgrp->top_cgroup) {
+ if ((err = cgroup_add_file(cgrp, NULL, &cft_release_agent)) < 0)
+ return err;
+ }
+
+ for_each_subsys(cgrp->root, ss) {
+ if (ss->populate && (err = ss->populate(ss, cgrp)) < 0)
return err;
}
static void init_cgroup_css(struct cgroup_subsys_state *css,
struct cgroup_subsys *ss,
- struct cgroup *cont)
+ struct cgroup *cgrp)
{
- css->cgroup = cont;
+ css->cgroup = cgrp;
atomic_set(&css->refcnt, 0);
css->flags = 0;
- if (cont == dummytop)
+ if (cgrp == dummytop)
set_bit(CSS_ROOT, &css->flags);
- BUG_ON(cont->subsys[ss->subsys_id]);
- cont->subsys[ss->subsys_id] = css;
+ BUG_ON(cgrp->subsys[ss->subsys_id]);
+ cgrp->subsys[ss->subsys_id] = css;
}
/*
static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
int mode)
{
- struct cgroup *cont;
+ struct cgroup *cgrp;
struct cgroupfs_root *root = parent->root;
int err = 0;
struct cgroup_subsys *ss;
struct super_block *sb = root->sb;
- cont = kzalloc(sizeof(*cont), GFP_KERNEL);
- if (!cont)
+ cgrp = kzalloc(sizeof(*cgrp), GFP_KERNEL);
+ if (!cgrp)
return -ENOMEM;
/* Grab a reference on the superblock so the hierarchy doesn't
mutex_lock(&cgroup_mutex);
- cont->flags = 0;
- INIT_LIST_HEAD(&cont->sibling);
- INIT_LIST_HEAD(&cont->children);
- INIT_LIST_HEAD(&cont->css_sets);
+ cgrp->flags = 0;
+ INIT_LIST_HEAD(&cgrp->sibling);
+ INIT_LIST_HEAD(&cgrp->children);
+ INIT_LIST_HEAD(&cgrp->css_sets);
+ INIT_LIST_HEAD(&cgrp->release_list);
- cont->parent = parent;
- cont->root = parent->root;
- cont->top_cgroup = parent->top_cgroup;
+ cgrp->parent = parent;
+ cgrp->root = parent->root;
+ cgrp->top_cgroup = parent->top_cgroup;
for_each_subsys(root, ss) {
- struct cgroup_subsys_state *css = ss->create(ss, cont);
+ struct cgroup_subsys_state *css = ss->create(ss, cgrp);
if (IS_ERR(css)) {
err = PTR_ERR(css);
goto err_destroy;
}
- init_cgroup_css(css, ss, cont);
+ init_cgroup_css(css, ss, cgrp);
}
- list_add(&cont->sibling, &cont->parent->children);
+ list_add(&cgrp->sibling, &cgrp->parent->children);
root->number_of_cgroups++;
- err = cgroup_create_dir(cont, dentry, mode);
+ err = cgroup_create_dir(cgrp, dentry, mode);
if (err < 0)
goto err_remove;
/* The cgroup directory was pre-locked for us */
- BUG_ON(!mutex_is_locked(&cont->dentry->d_inode->i_mutex));
+ BUG_ON(!mutex_is_locked(&cgrp->dentry->d_inode->i_mutex));
- err = cgroup_populate_dir(cont);
+ err = cgroup_populate_dir(cgrp);
/* If err < 0, we have a half-filled directory - oh well ;) */
mutex_unlock(&cgroup_mutex);
- mutex_unlock(&cont->dentry->d_inode->i_mutex);
+ mutex_unlock(&cgrp->dentry->d_inode->i_mutex);
return 0;
err_remove:
- list_del(&cont->sibling);
+ list_del(&cgrp->sibling);
root->number_of_cgroups--;
err_destroy:
for_each_subsys(root, ss) {
- if (cont->subsys[ss->subsys_id])
- ss->destroy(ss, cont);
+ if (cgrp->subsys[ss->subsys_id])
+ ss->destroy(ss, cgrp);
}
mutex_unlock(&cgroup_mutex);
/* Release the reference count that we took on the superblock */
deactivate_super(sb);
- kfree(cont);
+ kfree(cgrp);
return err;
}
return cgroup_create(c_parent, dentry, mode | S_IFDIR);
}
+static inline int cgroup_has_css_refs(struct cgroup *cgrp)
+{
+ /* Check the reference count on each subsystem. Since we
+ * already established that there are no tasks in the
+ * cgroup, if the css refcount is also 0, then there should
+ * be no outstanding references, so the subsystem is safe to
+ * destroy. We scan across all subsystems rather than using
+ * the per-hierarchy linked list of mounted subsystems since
+ * we can be called via check_for_release() with no
+ * synchronization other than RCU, and the subsystem linked
+ * list isn't RCU-safe */
+ int i;
+ for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
+ struct cgroup_subsys *ss = subsys[i];
+ struct cgroup_subsys_state *css;
+ /* Skip subsystems not in this hierarchy */
+ if (ss->root != cgrp->root)
+ continue;
+ css = cgrp->subsys[ss->subsys_id];
+ /* When called from check_for_release() it's possible
+ * that by this point the cgroup has been removed
+ * and the css deleted. But a false-positive doesn't
+ * matter, since it can only happen if the cgroup
+ * has been deleted and hence no longer needs the
+ * release agent to be called anyway. */
+ if (css && atomic_read(&css->refcnt)) {
+ return 1;
+ }
+ }
+ return 0;
+}
+
static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry)
{
- struct cgroup *cont = dentry->d_fsdata;
+ struct cgroup *cgrp = dentry->d_fsdata;
struct dentry *d;
struct cgroup *parent;
struct cgroup_subsys *ss;
struct super_block *sb;
struct cgroupfs_root *root;
- int css_busy = 0;
/* the vfs holds both inode->i_mutex already */
mutex_lock(&cgroup_mutex);
- if (atomic_read(&cont->count) != 0) {
+ if (atomic_read(&cgrp->count) != 0) {
mutex_unlock(&cgroup_mutex);
return -EBUSY;
}
- if (!list_empty(&cont->children)) {
+ if (!list_empty(&cgrp->children)) {
mutex_unlock(&cgroup_mutex);
return -EBUSY;
}
- parent = cont->parent;
- root = cont->root;
+ parent = cgrp->parent;
+ root = cgrp->root;
sb = root->sb;
- /* Check the reference count on each subsystem. Since we
- * already established that there are no tasks in the
- * cgroup, if the css refcount is also 0, then there should
- * be no outstanding references, so the subsystem is safe to
- * destroy */
- for_each_subsys(root, ss) {
- struct cgroup_subsys_state *css;
- css = cont->subsys[ss->subsys_id];
- if (atomic_read(&css->refcnt)) {
- css_busy = 1;
- break;
- }
- }
- if (css_busy) {
+ if (cgroup_has_css_refs(cgrp)) {
mutex_unlock(&cgroup_mutex);
return -EBUSY;
}
for_each_subsys(root, ss) {
- if (cont->subsys[ss->subsys_id])
- ss->destroy(ss, cont);
+ if (cgrp->subsys[ss->subsys_id])
+ ss->destroy(ss, cgrp);
}
- set_bit(CONT_REMOVED, &cont->flags);
+ spin_lock(&release_list_lock);
+ set_bit(CGRP_REMOVED, &cgrp->flags);
+ if (!list_empty(&cgrp->release_list))
+ list_del(&cgrp->release_list);
+ spin_unlock(&release_list_lock);
/* delete my sibling from parent->children */
- list_del(&cont->sibling);
- spin_lock(&cont->dentry->d_lock);
- d = dget(cont->dentry);
- cont->dentry = NULL;
+ list_del(&cgrp->sibling);
+ spin_lock(&cgrp->dentry->d_lock);
+ d = dget(cgrp->dentry);
+ cgrp->dentry = NULL;
spin_unlock(&d->d_lock);
cgroup_d_remove_dir(d);
dput(d);
root->number_of_cgroups--;
+ set_bit(CGRP_RELEASABLE, &parent->flags);
+ check_for_release(parent);
+
mutex_unlock(&cgroup_mutex);
/* Drop the active superblock reference that we took when we
* created the cgroup */
{
struct cgroup_subsys_state *css;
struct list_head *l;
- printk(KERN_ERR "Initializing cgroup subsys %s\n", ss->name);
+
+ printk(KERN_INFO "Initializing cgroup subsys %s\n", ss->name);
/* Create the top cgroup state for this subsystem */
ss->root = &rootnode;
/* If this subsystem requested that it be notified with fork
* events, we should send it one now for every process in the
* system */
- if (ss->fork) {
- struct task_struct *g, *p;
-
- read_lock(&tasklist_lock);
- do_each_thread(g, p) {
- ss->fork(ss, p);
- } while_each_thread(g, p);
- read_unlock(&tasklist_lock);
- }
+ if (ss->fork) {
+ struct task_struct *g, *p;
+
+ read_lock(&tasklist_lock);
+ do_each_thread(g, p) {
+ ss->fork(ss, p);
+ } while_each_thread(g, p);
+ read_unlock(&tasklist_lock);
+ }
need_forkexit_callback |= ss->fork || ss->exit;
init_task.cgroups = &init_css_set;
init_css_set_link.cg = &init_css_set;
- list_add(&init_css_set_link.cont_link_list,
+ list_add(&init_css_set_link.cgrp_link_list,
&rootnode.top_cgroup.css_sets);
list_add(&init_css_set_link.cg_link_list,
&init_css_set.cg_links);
BUG_ON(!ss->create);
BUG_ON(!ss->destroy);
if (ss->subsys_id != i) {
- printk(KERN_ERR "Subsys %s id == %d\n",
+ printk(KERN_ERR "cgroup: Subsys %s id == %d\n",
ss->name, ss->subsys_id);
BUG();
}
for_each_root(root) {
struct cgroup_subsys *ss;
- struct cgroup *cont;
+ struct cgroup *cgrp;
int subsys_id;
int count = 0;
seq_printf(m, "%s%s", count++ ? "," : "", ss->name);
seq_putc(m, ':');
get_first_subsys(&root->top_cgroup, NULL, &subsys_id);
- cont = task_cgroup(tsk, subsys_id);
- retval = cgroup_path(cont, buf, PAGE_SIZE);
+ cgrp = task_cgroup(tsk, subsys_id);
+ retval = cgroup_path(cgrp, buf, PAGE_SIZE);
if (retval < 0)
goto out_unlock;
seq_puts(m, buf);
static int proc_cgroupstats_show(struct seq_file *m, void *v)
{
int i;
- struct cgroupfs_root *root;
seq_puts(m, "#subsys_name\thierarchy\tnum_cgroups\n");
mutex_lock(&cgroup_mutex);
tsk->cgroups = &init_css_set;
task_unlock(tsk);
if (cg)
- put_css_set(cg);
+ put_css_set_taskexit(cg);
}
/**
dentry = lookup_one_len(nodename, parent->dentry, strlen(nodename));
if (IS_ERR(dentry)) {
printk(KERN_INFO
- "Couldn't allocate dentry for %s: %ld\n", nodename,
+ "cgroup: Couldn't allocate dentry for %s: %ld\n", nodename,
PTR_ERR(dentry));
ret = PTR_ERR(dentry);
goto out_release;
/* Create the cgroup directory, which also creates the cgroup */
ret = vfs_mkdir(inode, dentry, S_IFDIR | 0755);
- child = __d_cont(dentry);
+ child = __d_cgrp(dentry);
dput(dentry);
if (ret) {
printk(KERN_INFO
out_release:
mutex_unlock(&inode->i_mutex);
+
+ mutex_lock(&cgroup_mutex);
put_css_set(cg);
+ mutex_unlock(&cgroup_mutex);
deactivate_super(parent->root->sb);
return ret;
}
/*
- * See if "cont" is a descendant of the current task's cgroup in
+ * See if "cgrp" is a descendant of the current task's cgroup in
* the appropriate hierarchy
*
* If we are sending in dummytop, then presumably we are creating
*
* Called only by the ns (nsproxy) cgroup.
*/
-int cgroup_is_descendant(const struct cgroup *cont)
+int cgroup_is_descendant(const struct cgroup *cgrp)
{
int ret;
struct cgroup *target;
int subsys_id;
- if (cont == dummytop)
+ if (cgrp == dummytop)
return 1;
- get_first_subsys(cont, NULL, &subsys_id);
+ get_first_subsys(cgrp, NULL, &subsys_id);
target = task_cgroup(current, subsys_id);
- while (cont != target && cont!= cont->top_cgroup)
- cont = cont->parent;
- ret = (cont == target);
+ while (cgrp != target && cgrp!= cgrp->top_cgroup)
+ cgrp = cgrp->parent;
+ ret = (cgrp == target);
return ret;
}
+
+static void check_for_release(struct cgroup *cgrp)
+{
+ /* All of these checks rely on RCU to keep the cgroup
+ * structure alive */
+ if (cgroup_is_releasable(cgrp) && !atomic_read(&cgrp->count)
+ && list_empty(&cgrp->children) && !cgroup_has_css_refs(cgrp)) {
+ /* Control Group is currently removeable. If it's not
+ * already queued for a userspace notification, queue
+ * it now */
+ int need_schedule_work = 0;
+ spin_lock(&release_list_lock);
+ if (!cgroup_is_removed(cgrp) &&
+ list_empty(&cgrp->release_list)) {
+ list_add(&cgrp->release_list, &release_list);
+ need_schedule_work = 1;
+ }
+ spin_unlock(&release_list_lock);
+ if (need_schedule_work)
+ schedule_work(&release_agent_work);
+ }
+}
+
+void __css_put(struct cgroup_subsys_state *css)
+{
+ struct cgroup *cgrp = css->cgroup;
+ rcu_read_lock();
+ if (atomic_dec_and_test(&css->refcnt) && notify_on_release(cgrp)) {
+ set_bit(CGRP_RELEASABLE, &cgrp->flags);
+ check_for_release(cgrp);
+ }
+ rcu_read_unlock();
+}
+
+/*
+ * Notify userspace when a cgroup is released, by running the
+ * configured release agent with the name of the cgroup (path
+ * relative to the root of cgroup file system) as the argument.
+ *
+ * Most likely, this user command will try to rmdir this cgroup.
+ *
+ * This races with the possibility that some other task will be
+ * attached to this cgroup before it is removed, or that some other
+ * user task will 'mkdir' a child cgroup of this cgroup. That's ok.
+ * The presumed 'rmdir' will fail quietly if this cgroup is no longer
+ * unused, and this cgroup will be reprieved from its death sentence,
+ * to continue to serve a useful existence. Next time it's released,
+ * we will get notified again, if it still has 'notify_on_release' set.
+ *
+ * The final arg to call_usermodehelper() is UMH_WAIT_EXEC, which
+ * means only wait until the task is successfully execve()'d. The
+ * separate release agent task is forked by call_usermodehelper(),
+ * then control in this thread returns here, without waiting for the
+ * release agent task. We don't bother to wait because the caller of
+ * this routine has no use for the exit status of the release agent
+ * task, so no sense holding our caller up for that.
+ *
+ */
+
+static void cgroup_release_agent(struct work_struct *work)
+{
+ BUG_ON(work != &release_agent_work);
+ mutex_lock(&cgroup_mutex);
+ spin_lock(&release_list_lock);
+ while (!list_empty(&release_list)) {
+ char *argv[3], *envp[3];
+ int i;
+ char *pathbuf;
+ struct cgroup *cgrp = list_entry(release_list.next,
+ struct cgroup,
+ release_list);
+ list_del_init(&cgrp->release_list);
+ spin_unlock(&release_list_lock);
+ pathbuf = kmalloc(PAGE_SIZE, GFP_KERNEL);
+ if (!pathbuf) {
+ spin_lock(&release_list_lock);
+ continue;
+ }
+
+ if (cgroup_path(cgrp, pathbuf, PAGE_SIZE) < 0) {
+ kfree(pathbuf);
+ spin_lock(&release_list_lock);
+ continue;
+ }
+
+ i = 0;
+ argv[i++] = cgrp->root->release_agent_path;
+ argv[i++] = (char *)pathbuf;
+ argv[i] = NULL;
+
+ i = 0;
+ /* minimal command environment */
+ envp[i++] = "HOME=/";
+ envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
+ envp[i] = NULL;
+
+ /* Drop the lock while we invoke the usermode helper,
+ * since the exec could involve hitting disk and hence
+ * be a slow process */
+ mutex_unlock(&cgroup_mutex);
+ call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC);
+ kfree(pathbuf);
+ mutex_lock(&cgroup_mutex);
+ spin_lock(&release_list_lock);
+ }
+ spin_unlock(&release_list_lock);
+ mutex_unlock(&cgroup_mutex);
+}
projects / linux-2.6 / blobdiff