* The default hierarchy always exists but is hidden until mounted for the
* first time. This is for backward compatibility.
*/
-static bool cgrp_dfl_root_visible;
+static bool cgrp_dfl_visible;
+
+/* Controllers blocked by the commandline in v1 */
+static u16 cgroup_no_v1_mask;
/* some controllers are not supported in the default hierarchy */
-static unsigned long cgrp_dfl_root_inhibit_ss_mask;
+static u16 cgrp_dfl_inhibit_ss_mask;
+
+/* some controllers are implicitly enabled on the default hierarchy */
+static unsigned long cgrp_dfl_implicit_ss_mask;
/* The list of hierarchy roots */
* fork/exit handlers to call. This avoids us having to do extra work in the
* fork/exit path to check which subsystems have fork/exit callbacks.
*/
-static unsigned long have_fork_callback __read_mostly;
-static unsigned long have_exit_callback __read_mostly;
-static unsigned long have_free_callback __read_mostly;
+static u16 have_fork_callback __read_mostly;
+static u16 have_exit_callback __read_mostly;
+static u16 have_free_callback __read_mostly;
/* Ditto for the can_fork callback. */
-static unsigned long have_canfork_callback __read_mostly;
+static u16 have_canfork_callback __read_mostly;
static struct file_system_type cgroup2_fs_type;
static struct cftype cgroup_dfl_base_files[];
static struct cftype cgroup_legacy_base_files[];
-static int rebind_subsystems(struct cgroup_root *dst_root,
- unsigned long ss_mask);
+static int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask);
+static void cgroup_lock_and_drain_offline(struct cgroup *cgrp);
+static int cgroup_apply_control(struct cgroup *cgrp);
+static void cgroup_finalize_control(struct cgroup *cgrp, int ret);
static void css_task_iter_advance(struct css_task_iter *it);
static int cgroup_destroy_locked(struct cgroup *cgrp);
-static int create_css(struct cgroup *cgrp, struct cgroup_subsys *ss,
- bool visible);
+static struct cgroup_subsys_state *css_create(struct cgroup *cgrp,
+ struct cgroup_subsys *ss);
static void css_release(struct percpu_ref *ref);
static void kill_css(struct cgroup_subsys_state *css);
static int cgroup_addrm_files(struct cgroup_subsys_state *css,
*/
static bool cgroup_ssid_enabled(int ssid)
{
+ if (CGROUP_SUBSYS_COUNT == 0)
+ return false;
+
return static_key_enabled(cgroup_subsys_enabled_key[ssid]);
}
+static bool cgroup_ssid_no_v1(int ssid)
+{
+ return cgroup_no_v1_mask & (1 << ssid);
+}
+
/**
* cgroup_on_dfl - test whether a cgroup is on the default hierarchy
* @cgrp: the cgroup of interest
return NULL;
}
+/* subsystems visibly enabled on a cgroup */
+static u16 cgroup_control(struct cgroup *cgrp)
+{
+ struct cgroup *parent = cgroup_parent(cgrp);
+ u16 root_ss_mask = cgrp->root->subsys_mask;
+
+ if (parent)
+ return parent->subtree_control;
+
+ if (cgroup_on_dfl(cgrp))
+ root_ss_mask &= ~(cgrp_dfl_inhibit_ss_mask |
+ cgrp_dfl_implicit_ss_mask);
+ return root_ss_mask;
+}
+
+/* subsystems enabled on a cgroup */
+static u16 cgroup_ss_mask(struct cgroup *cgrp)
+{
+ struct cgroup *parent = cgroup_parent(cgrp);
+
+ if (parent)
+ return parent->subtree_ss_mask;
+
+ return cgrp->root->subsys_mask;
+}
+
/**
* cgroup_css - obtain a cgroup's css for the specified subsystem
* @cgrp: the cgroup of interest
if (!ss)
return &cgrp->self;
- if (!(cgrp->root->subsys_mask & (1 << ss->id)))
- return NULL;
-
/*
* This function is used while updating css associations and thus
- * can't test the csses directly. Use ->child_subsys_mask.
+ * can't test the csses directly. Test ss_mask.
*/
- while (cgroup_parent(cgrp) &&
- !(cgroup_parent(cgrp)->child_subsys_mask & (1 << ss->id)))
+ while (!(cgroup_ss_mask(cgrp) & (1 << ss->id))) {
cgrp = cgroup_parent(cgrp);
+ if (!cgrp)
+ return NULL;
+ }
return cgroup_css(cgrp, ss);
}
(((ss) = cgroup_subsys[ssid]) || true); (ssid)++)
/**
- * for_each_subsys_which - filter for_each_subsys with a bitmask
+ * do_each_subsys_mask - filter for_each_subsys with a bitmask
* @ss: the iteration cursor
* @ssid: the index of @ss, CGROUP_SUBSYS_COUNT after reaching the end
- * @ss_maskp: a pointer to the bitmask
+ * @ss_mask: the bitmask
*
* The block will only run for cases where the ssid-th bit (1 << ssid) of
- * mask is set to 1.
+ * @ss_mask is set.
*/
-#define for_each_subsys_which(ss, ssid, ss_maskp) \
- if (!CGROUP_SUBSYS_COUNT) /* to avoid spurious gcc warning */ \
+#define do_each_subsys_mask(ss, ssid, ss_mask) do { \
+ unsigned long __ss_mask = (ss_mask); \
+ if (!CGROUP_SUBSYS_COUNT) { /* to avoid spurious gcc warning */ \
(ssid) = 0; \
- else \
- for_each_set_bit(ssid, ss_maskp, CGROUP_SUBSYS_COUNT) \
- if (((ss) = cgroup_subsys[ssid]) && false) \
- break; \
- else
+ break; \
+ } \
+ for_each_set_bit(ssid, &__ss_mask, CGROUP_SUBSYS_COUNT) { \
+ (ss) = cgroup_subsys[ssid]; \
+ {
+
+#define while_each_subsys_mask() \
+ } \
+ } \
+} while (false)
/* iterate across the hierarchies */
#define for_each_root(root) \
; \
else
+/* walk live descendants in preorder */
+#define cgroup_for_each_live_descendant_pre(dsct, d_css, cgrp) \
+ css_for_each_descendant_pre((d_css), cgroup_css((cgrp), NULL)) \
+ if (({ lockdep_assert_held(&cgroup_mutex); \
+ (dsct) = (d_css)->cgroup; \
+ cgroup_is_dead(dsct); })) \
+ ; \
+ else
+
+/* walk live descendants in postorder */
+#define cgroup_for_each_live_descendant_post(dsct, d_css, cgrp) \
+ css_for_each_descendant_post((d_css), cgroup_css((cgrp), NULL)) \
+ if (({ lockdep_assert_held(&cgroup_mutex); \
+ (dsct) = (d_css)->cgroup; \
+ cgroup_is_dead(dsct); })) \
+ ; \
+ else
+
static void cgroup_release_agent(struct work_struct *work);
static void check_for_release(struct cgroup *cgrp);
{
lockdep_assert_held(&css_set_lock);
+ if (to_cset && !css_set_populated(to_cset))
+ css_set_update_populated(to_cset, true);
+
if (from_cset) {
struct css_task_iter *it, *pos;
*/
WARN_ON_ONCE(task->flags & PF_EXITING);
- if (!css_set_populated(to_cset))
- css_set_update_populated(to_cset, true);
rcu_assign_pointer(task->cgroups, to_cset);
list_add_tail(&task->cg_list, use_mg_tasks ? &to_cset->mg_tasks :
&to_cset->tasks);
struct cgroup *cgrp = &root->cgrp;
struct cgrp_cset_link *link, *tmp_link;
- mutex_lock(&cgroup_mutex);
+ cgroup_lock_and_drain_offline(&cgrp_dfl_root.cgrp);
BUG_ON(atomic_read(&root->nr_cgrps));
BUG_ON(!list_empty(&cgrp->self.children));
/* Rebind all subsystems back to the default hierarchy */
- rebind_subsystems(&cgrp_dfl_root, root->subsys_mask);
+ WARN_ON(rebind_subsystems(&cgrp_dfl_root, root->subsys_mask));
/*
* Release all the links from cset_links to this hierarchy's
}
/**
- * cgroup_calc_child_subsys_mask - calculate child_subsys_mask
- * @cgrp: the target cgroup
+ * cgroup_calc_subtree_ss_mask - calculate subtree_ss_mask
* @subtree_control: the new subtree_control mask to consider
+ * @this_ss_mask: available subsystems
*
* On the default hierarchy, a subsystem may request other subsystems to be
* enabled together through its ->depends_on mask. In such cases, more
* subsystems than specified in "cgroup.subtree_control" may be enabled.
*
* This function calculates which subsystems need to be enabled if
- * @subtree_control is to be applied to @cgrp. The returned mask is always
- * a superset of @subtree_control and follows the usual hierarchy rules.
+ * @subtree_control is to be applied while restricted to @this_ss_mask.
*/
-static unsigned long cgroup_calc_child_subsys_mask(struct cgroup *cgrp,
- unsigned long subtree_control)
+static u16 cgroup_calc_subtree_ss_mask(u16 subtree_control, u16 this_ss_mask)
{
- struct cgroup *parent = cgroup_parent(cgrp);
- unsigned long cur_ss_mask = subtree_control;
+ u16 cur_ss_mask = subtree_control;
struct cgroup_subsys *ss;
int ssid;
lockdep_assert_held(&cgroup_mutex);
- if (!cgroup_on_dfl(cgrp))
- return cur_ss_mask;
+ cur_ss_mask |= cgrp_dfl_implicit_ss_mask;
while (true) {
- unsigned long new_ss_mask = cur_ss_mask;
+ u16 new_ss_mask = cur_ss_mask;
- for_each_subsys_which(ss, ssid, &cur_ss_mask)
+ do_each_subsys_mask(ss, ssid, cur_ss_mask) {
new_ss_mask |= ss->depends_on;
+ } while_each_subsys_mask();
/*
* Mask out subsystems which aren't available. This can
* happen only if some depended-upon subsystems were bound
* to non-default hierarchies.
*/
- if (parent)
- new_ss_mask &= parent->child_subsys_mask;
- else
- new_ss_mask &= cgrp->root->subsys_mask;
+ new_ss_mask &= this_ss_mask;
if (new_ss_mask == cur_ss_mask)
break;
return cur_ss_mask;
}
-/**
- * cgroup_refresh_child_subsys_mask - update child_subsys_mask
- * @cgrp: the target cgroup
- *
- * Update @cgrp->child_subsys_mask according to the current
- * @cgrp->subtree_control using cgroup_calc_child_subsys_mask().
- */
-static void cgroup_refresh_child_subsys_mask(struct cgroup *cgrp)
-{
- cgrp->child_subsys_mask =
- cgroup_calc_child_subsys_mask(cgrp, cgrp->subtree_control);
-}
-
/**
* cgroup_kn_unlock - unlocking helper for cgroup kernfs methods
* @kn: the kernfs_node being serviced
/**
* cgroup_kn_lock_live - locking helper for cgroup kernfs methods
* @kn: the kernfs_node being serviced
+ * @drain_offline: perform offline draining on the cgroup
*
* This helper is to be used by a cgroup kernfs method currently servicing
* @kn. It breaks the active protection, performs cgroup locking and
* verifies that the associated cgroup is alive. Returns the cgroup if
* alive; otherwise, %NULL. A successful return should be undone by a
- * matching cgroup_kn_unlock() invocation.
+ * matching cgroup_kn_unlock() invocation. If @drain_offline is %true, the
+ * cgroup is drained of offlining csses before return.
*
* Any cgroup kernfs method implementation which requires locking the
* associated cgroup should use this helper. It avoids nesting cgroup
* locking under kernfs active protection and allows all kernfs operations
* including self-removal.
*/
-static struct cgroup *cgroup_kn_lock_live(struct kernfs_node *kn)
+static struct cgroup *cgroup_kn_lock_live(struct kernfs_node *kn,
+ bool drain_offline)
{
struct cgroup *cgrp;
return NULL;
kernfs_break_active_protection(kn);
- mutex_lock(&cgroup_mutex);
+ if (drain_offline)
+ cgroup_lock_and_drain_offline(cgrp);
+ else
+ mutex_lock(&cgroup_mutex);
if (!cgroup_is_dead(cgrp))
return cgrp;
/**
* css_clear_dir - remove subsys files in a cgroup directory
* @css: taget css
- * @cgrp_override: specify if target cgroup is different from css->cgroup
*/
-static void css_clear_dir(struct cgroup_subsys_state *css,
- struct cgroup *cgrp_override)
+static void css_clear_dir(struct cgroup_subsys_state *css)
{
- struct cgroup *cgrp = cgrp_override ?: css->cgroup;
+ struct cgroup *cgrp = css->cgroup;
struct cftype *cfts;
+ if (!(css->flags & CSS_VISIBLE))
+ return;
+
+ css->flags &= ~CSS_VISIBLE;
+
list_for_each_entry(cfts, &css->ss->cfts, node)
cgroup_addrm_files(css, cgrp, cfts, false);
}
/**
* css_populate_dir - create subsys files in a cgroup directory
* @css: target css
- * @cgrp_overried: specify if target cgroup is different from css->cgroup
*
* On failure, no file is added.
*/
-static int css_populate_dir(struct cgroup_subsys_state *css,
- struct cgroup *cgrp_override)
+static int css_populate_dir(struct cgroup_subsys_state *css)
{
- struct cgroup *cgrp = cgrp_override ?: css->cgroup;
+ struct cgroup *cgrp = css->cgroup;
struct cftype *cfts, *failed_cfts;
int ret;
+ if ((css->flags & CSS_VISIBLE) || !cgrp->kn)
+ return 0;
+
if (!css->ss) {
if (cgroup_on_dfl(cgrp))
cfts = cgroup_dfl_base_files;
goto err;
}
}
+
+ css->flags |= CSS_VISIBLE;
+
return 0;
err:
list_for_each_entry(cfts, &css->ss->cfts, node) {
return ret;
}
-static int rebind_subsystems(struct cgroup_root *dst_root,
- unsigned long ss_mask)
+static int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask)
{
struct cgroup *dcgrp = &dst_root->cgrp;
struct cgroup_subsys *ss;
- unsigned long tmp_ss_mask;
int ssid, i, ret;
lockdep_assert_held(&cgroup_mutex);
- for_each_subsys_which(ss, ssid, &ss_mask) {
- /* if @ss has non-root csses attached to it, can't move */
- if (css_next_child(NULL, cgroup_css(&ss->root->cgrp, ss)))
+ do_each_subsys_mask(ss, ssid, ss_mask) {
+ /*
+ * If @ss has non-root csses attached to it, can't move.
+ * If @ss is an implicit controller, it is exempt from this
+ * rule and can be stolen.
+ */
+ if (css_next_child(NULL, cgroup_css(&ss->root->cgrp, ss)) &&
+ !ss->implicit_on_dfl)
return -EBUSY;
/* can't move between two non-dummy roots either */
if (ss->root != &cgrp_dfl_root && dst_root != &cgrp_dfl_root)
return -EBUSY;
- }
-
- /* skip creating root files on dfl_root for inhibited subsystems */
- tmp_ss_mask = ss_mask;
- if (dst_root == &cgrp_dfl_root)
- tmp_ss_mask &= ~cgrp_dfl_root_inhibit_ss_mask;
-
- for_each_subsys_which(ss, ssid, &tmp_ss_mask) {
- struct cgroup *scgrp = &ss->root->cgrp;
- int tssid;
-
- ret = css_populate_dir(cgroup_css(scgrp, ss), dcgrp);
- if (!ret)
- continue;
-
- /*
- * Rebinding back to the default root is not allowed to
- * fail. Using both default and non-default roots should
- * be rare. Moving subsystems back and forth even more so.
- * Just warn about it and continue.
- */
- if (dst_root == &cgrp_dfl_root) {
- if (cgrp_dfl_root_visible) {
- pr_warn("failed to create files (%d) while rebinding 0x%lx to default root\n",
- ret, ss_mask);
- pr_warn("you may retry by moving them to a different hierarchy and unbinding\n");
- }
- continue;
- }
-
- for_each_subsys_which(ss, tssid, &tmp_ss_mask) {
- if (tssid == ssid)
- break;
- css_clear_dir(cgroup_css(scgrp, ss), dcgrp);
- }
- return ret;
- }
+ } while_each_subsys_mask();
- /*
- * Nothing can fail from this point on. Remove files for the
- * removed subsystems and rebind each subsystem.
- */
- for_each_subsys_which(ss, ssid, &ss_mask) {
+ do_each_subsys_mask(ss, ssid, ss_mask) {
struct cgroup_root *src_root = ss->root;
struct cgroup *scgrp = &src_root->cgrp;
struct cgroup_subsys_state *css = cgroup_css(scgrp, ss);
WARN_ON(!css || cgroup_css(dcgrp, ss));
- css_clear_dir(css, NULL);
+ /* disable from the source */
+ src_root->subsys_mask &= ~(1 << ssid);
+ WARN_ON(cgroup_apply_control(scgrp));
+ cgroup_finalize_control(scgrp, 0);
+ /* rebind */
RCU_INIT_POINTER(scgrp->subsys[ssid], NULL);
rcu_assign_pointer(dcgrp->subsys[ssid], css);
ss->root = dst_root;
&dcgrp->e_csets[ss->id]);
spin_unlock_bh(&css_set_lock);
- src_root->subsys_mask &= ~(1 << ssid);
- scgrp->subtree_control &= ~(1 << ssid);
- cgroup_refresh_child_subsys_mask(scgrp);
-
/* default hierarchy doesn't enable controllers by default */
dst_root->subsys_mask |= 1 << ssid;
if (dst_root == &cgrp_dfl_root) {
static_branch_enable(cgroup_subsys_on_dfl_key[ssid]);
} else {
dcgrp->subtree_control |= 1 << ssid;
- cgroup_refresh_child_subsys_mask(dcgrp);
static_branch_disable(cgroup_subsys_on_dfl_key[ssid]);
}
+ ret = cgroup_apply_control(dcgrp);
+ if (ret)
+ pr_warn("partial failure to rebind %s controller (err=%d)\n",
+ ss->name, ret);
+
if (ss->bind)
ss->bind(css);
- }
+ } while_each_subsys_mask();
kernfs_activate(dcgrp->kn);
return 0;
}
struct cgroup_sb_opts {
- unsigned long subsys_mask;
+ u16 subsys_mask;
unsigned int flags;
char *release_agent;
bool cpuset_clone_children;
{
char *token, *o = data;
bool all_ss = false, one_ss = false;
- unsigned long mask = -1UL;
+ u16 mask = U16_MAX;
struct cgroup_subsys *ss;
int nr_opts = 0;
int i;
#ifdef CONFIG_CPUSETS
- mask = ~(1U << cpuset_cgrp_id);
+ mask = ~((u16)1 << cpuset_cgrp_id);
#endif
memset(opts, 0, sizeof(*opts));
continue;
if (!cgroup_ssid_enabled(i))
continue;
+ if (cgroup_ssid_no_v1(i))
+ continue;
/* Mutually exclusive option 'all' + subsystem name */
if (all_ss)
*/
if (all_ss || (!one_ss && !opts->none && !opts->name))
for_each_subsys(ss, i)
- if (cgroup_ssid_enabled(i))
+ if (cgroup_ssid_enabled(i) && !cgroup_ssid_no_v1(i))
opts->subsys_mask |= (1 << i);
/*
int ret = 0;
struct cgroup_root *root = cgroup_root_from_kf(kf_root);
struct cgroup_sb_opts opts;
- unsigned long added_mask, removed_mask;
+ u16 added_mask, removed_mask;
if (root == &cgrp_dfl_root) {
pr_err("remount is not allowed\n");
return -EINVAL;
}
- mutex_lock(&cgroup_mutex);
+ cgroup_lock_and_drain_offline(&cgrp_dfl_root.cgrp);
/* See what subsystems are wanted */
ret = parse_cgroupfs_options(data, &opts);
if (ret)
goto out_unlock;
- rebind_subsystems(&cgrp_dfl_root, removed_mask);
+ WARN_ON(rebind_subsystems(&cgrp_dfl_root, removed_mask));
if (opts.release_agent) {
spin_lock(&release_agent_path_lock);
set_bit(CGRP_CPUSET_CLONE_CHILDREN, &root->cgrp.flags);
}
-static int cgroup_setup_root(struct cgroup_root *root, unsigned long ss_mask)
+static int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask)
{
LIST_HEAD(tmp_links);
struct cgroup *root_cgrp = &root->cgrp;
/*
* We're accessing css_set_count without locking css_set_lock here,
* but that's OK - it can only be increased by someone holding
- * cgroup_lock, and that's us. The worst that can happen is that we
- * have some link structures left over
+ * cgroup_lock, and that's us. Later rebinding may disable
+ * controllers on the default hierarchy and thus create new csets,
+ * which can't be more than the existing ones. Allocate 2x.
*/
- ret = allocate_cgrp_cset_links(css_set_count, &tmp_links);
+ ret = allocate_cgrp_cset_links(2 * css_set_count, &tmp_links);
if (ret)
goto cancel_ref;
}
root_cgrp->kn = root->kf_root->kn;
- ret = css_populate_dir(&root_cgrp->self, NULL);
+ ret = css_populate_dir(&root_cgrp->self);
if (ret)
goto destroy_root;
pr_err("cgroup2: unknown option \"%s\"\n", (char *)data);
return ERR_PTR(-EINVAL);
}
- cgrp_dfl_root_visible = true;
+ cgrp_dfl_visible = true;
root = &cgrp_dfl_root;
cgroup_get(&root->cgrp);
goto out_mount;
}
- mutex_lock(&cgroup_mutex);
+ cgroup_lock_and_drain_offline(&cgrp_dfl_root.cgrp);
/* First find the desired set of subsystems */
ret = parse_cgroupfs_options(data, &opts);
}
/**
- * cgroup_taskset_migrate - migrate a taskset to a cgroup
+ * cgroup_taskset_migrate - migrate a taskset
* @tset: taget taskset
- * @dst_cgrp: destination cgroup
+ * @root: cgroup root the migration is taking place on
*
- * Migrate tasks in @tset to @dst_cgrp. This function fails iff one of the
- * ->can_attach callbacks fails and guarantees that either all or none of
- * the tasks in @tset are migrated. @tset is consumed regardless of
- * success.
+ * Migrate tasks in @tset as setup by migration preparation functions.
+ * This function fails iff one of the ->can_attach callbacks fails and
+ * guarantees that either all or none of the tasks in @tset are migrated.
+ * @tset is consumed regardless of success.
*/
static int cgroup_taskset_migrate(struct cgroup_taskset *tset,
- struct cgroup *dst_cgrp)
+ struct cgroup_root *root)
{
- struct cgroup_subsys_state *css, *failed_css = NULL;
+ struct cgroup_subsys *ss;
struct task_struct *task, *tmp_task;
struct css_set *cset, *tmp_cset;
- int i, ret;
+ int ssid, failed_ssid, ret;
/* methods shouldn't be called if no task is actually migrating */
if (list_empty(&tset->src_csets))
return 0;
/* check that we can legitimately attach to the cgroup */
- for_each_e_css(css, i, dst_cgrp) {
- if (css->ss->can_attach) {
- tset->ssid = i;
- ret = css->ss->can_attach(tset);
+ do_each_subsys_mask(ss, ssid, root->subsys_mask) {
+ if (ss->can_attach) {
+ tset->ssid = ssid;
+ ret = ss->can_attach(tset);
if (ret) {
- failed_css = css;
+ failed_ssid = ssid;
goto out_cancel_attach;
}
}
- }
+ } while_each_subsys_mask();
/*
* Now that we're guaranteed success, proceed to move all tasks to
*/
tset->csets = &tset->dst_csets;
- for_each_e_css(css, i, dst_cgrp) {
- if (css->ss->attach) {
- tset->ssid = i;
- css->ss->attach(tset);
+ do_each_subsys_mask(ss, ssid, root->subsys_mask) {
+ if (ss->attach) {
+ tset->ssid = ssid;
+ ss->attach(tset);
}
- }
+ } while_each_subsys_mask();
ret = 0;
goto out_release_tset;
out_cancel_attach:
- for_each_e_css(css, i, dst_cgrp) {
- if (css == failed_css)
+ do_each_subsys_mask(ss, ssid, root->subsys_mask) {
+ if (ssid == failed_ssid)
break;
- if (css->ss->cancel_attach) {
- tset->ssid = i;
- css->ss->cancel_attach(tset);
+ if (ss->cancel_attach) {
+ tset->ssid = ssid;
+ ss->cancel_attach(tset);
}
- }
+ } while_each_subsys_mask();
out_release_tset:
spin_lock_bh(&css_set_lock);
list_splice_init(&tset->dst_csets, &tset->src_csets);
return ret;
}
+/**
+ * cgroup_may_migrate_to - verify whether a cgroup can be migration destination
+ * @dst_cgrp: destination cgroup to test
+ *
+ * On the default hierarchy, except for the root, subtree_control must be
+ * zero for migration destination cgroups with tasks so that child cgroups
+ * don't compete against tasks.
+ */
+static bool cgroup_may_migrate_to(struct cgroup *dst_cgrp)
+{
+ return !cgroup_on_dfl(dst_cgrp) || !cgroup_parent(dst_cgrp) ||
+ !dst_cgrp->subtree_control;
+}
+
/**
* cgroup_migrate_finish - cleanup after attach
* @preloaded_csets: list of preloaded css_sets
spin_lock_bh(&css_set_lock);
list_for_each_entry_safe(cset, tmp_cset, preloaded_csets, mg_preload_node) {
cset->mg_src_cgrp = NULL;
+ cset->mg_dst_cgrp = NULL;
cset->mg_dst_cset = NULL;
list_del_init(&cset->mg_preload_node);
put_css_set_locked(cset);
lockdep_assert_held(&cgroup_mutex);
lockdep_assert_held(&css_set_lock);
+ /*
+ * If ->dead, @src_set is associated with one or more dead cgroups
+ * and doesn't contain any migratable tasks. Ignore it early so
+ * that the rest of migration path doesn't get confused by it.
+ */
+ if (src_cset->dead)
+ return;
+
src_cgrp = cset_cgroup_from_root(src_cset, dst_cgrp->root);
if (!list_empty(&src_cset->mg_preload_node))
return;
WARN_ON(src_cset->mg_src_cgrp);
+ WARN_ON(src_cset->mg_dst_cgrp);
WARN_ON(!list_empty(&src_cset->mg_tasks));
WARN_ON(!list_empty(&src_cset->mg_node));
src_cset->mg_src_cgrp = src_cgrp;
+ src_cset->mg_dst_cgrp = dst_cgrp;
get_css_set(src_cset);
list_add(&src_cset->mg_preload_node, preloaded_csets);
}
/**
* cgroup_migrate_prepare_dst - prepare destination css_sets for migration
- * @dst_cgrp: the destination cgroup (may be %NULL)
* @preloaded_csets: list of preloaded source css_sets
*
- * Tasks are about to be moved to @dst_cgrp and all the source css_sets
- * have been preloaded to @preloaded_csets. This function looks up and
- * pins all destination css_sets, links each to its source, and append them
- * to @preloaded_csets. If @dst_cgrp is %NULL, the destination of each
- * source css_set is assumed to be its cgroup on the default hierarchy.
+ * Tasks are about to be moved and all the source css_sets have been
+ * preloaded to @preloaded_csets. This function looks up and pins all
+ * destination css_sets, links each to its source, and append them to
+ * @preloaded_csets.
*
* This function must be called after cgroup_migrate_add_src() has been
* called on each migration source css_set. After migration is performed
* using cgroup_migrate(), cgroup_migrate_finish() must be called on
* @preloaded_csets.
*/
-static int cgroup_migrate_prepare_dst(struct cgroup *dst_cgrp,
- struct list_head *preloaded_csets)
+static int cgroup_migrate_prepare_dst(struct list_head *preloaded_csets)
{
LIST_HEAD(csets);
struct css_set *src_cset, *tmp_cset;
lockdep_assert_held(&cgroup_mutex);
- /*
- * Except for the root, child_subsys_mask must be zero for a cgroup
- * with tasks so that child cgroups don't compete against tasks.
- */
- if (dst_cgrp && cgroup_on_dfl(dst_cgrp) && cgroup_parent(dst_cgrp) &&
- dst_cgrp->child_subsys_mask)
- return -EBUSY;
-
/* look up the dst cset for each src cset and link it to src */
list_for_each_entry_safe(src_cset, tmp_cset, preloaded_csets, mg_preload_node) {
struct css_set *dst_cset;
- dst_cset = find_css_set(src_cset,
- dst_cgrp ?: src_cset->dfl_cgrp);
+ dst_cset = find_css_set(src_cset, src_cset->mg_dst_cgrp);
if (!dst_cset)
goto err;
*/
if (src_cset == dst_cset) {
src_cset->mg_src_cgrp = NULL;
+ src_cset->mg_dst_cgrp = NULL;
list_del_init(&src_cset->mg_preload_node);
put_css_set(src_cset);
put_css_set(dst_cset);
* cgroup_migrate - migrate a process or task to a cgroup
* @leader: the leader of the process or the task to migrate
* @threadgroup: whether @leader points to the whole process or a single task
- * @cgrp: the destination cgroup
+ * @root: cgroup root migration is taking place on
*
- * Migrate a process or task denoted by @leader to @cgrp. If migrating a
- * process, the caller must be holding cgroup_threadgroup_rwsem. The
- * caller is also responsible for invoking cgroup_migrate_add_src() and
+ * Migrate a process or task denoted by @leader. If migrating a process,
+ * the caller must be holding cgroup_threadgroup_rwsem. The caller is also
+ * responsible for invoking cgroup_migrate_add_src() and
* cgroup_migrate_prepare_dst() on the targets before invoking this
* function and following up with cgroup_migrate_finish().
*
* actually starting migrating.
*/
static int cgroup_migrate(struct task_struct *leader, bool threadgroup,
- struct cgroup *cgrp)
+ struct cgroup_root *root)
{
struct cgroup_taskset tset = CGROUP_TASKSET_INIT(tset);
struct task_struct *task;
rcu_read_unlock();
spin_unlock_bh(&css_set_lock);
- return cgroup_taskset_migrate(&tset, cgrp);
+ return cgroup_taskset_migrate(&tset, root);
}
/**
struct task_struct *task;
int ret;
+ if (!cgroup_may_migrate_to(dst_cgrp))
+ return -EBUSY;
+
/* look up all src csets */
spin_lock_bh(&css_set_lock);
rcu_read_lock();
spin_unlock_bh(&css_set_lock);
/* prepare dst csets and commit */
- ret = cgroup_migrate_prepare_dst(dst_cgrp, &preloaded_csets);
+ ret = cgroup_migrate_prepare_dst(&preloaded_csets);
if (!ret)
- ret = cgroup_migrate(leader, threadgroup, dst_cgrp);
+ ret = cgroup_migrate(leader, threadgroup, dst_cgrp->root);
cgroup_migrate_finish(&preloaded_csets);
return ret;
if (kstrtoint(strstrip(buf), 0, &pid) || pid < 0)
return -EINVAL;
- cgrp = cgroup_kn_lock_live(of->kn);
+ cgrp = cgroup_kn_lock_live(of->kn, false);
if (!cgrp)
return -ENODEV;
BUILD_BUG_ON(sizeof(cgrp->root->release_agent_path) < PATH_MAX);
- cgrp = cgroup_kn_lock_live(of->kn);
+ cgrp = cgroup_kn_lock_live(of->kn, false);
if (!cgrp)
return -ENODEV;
spin_lock(&release_agent_path_lock);
return 0;
}
-static void cgroup_print_ss_mask(struct seq_file *seq, unsigned long ss_mask)
+static void cgroup_print_ss_mask(struct seq_file *seq, u16 ss_mask)
{
struct cgroup_subsys *ss;
bool printed = false;
int ssid;
- for_each_subsys_which(ss, ssid, &ss_mask) {
+ do_each_subsys_mask(ss, ssid, ss_mask) {
if (printed)
seq_putc(seq, ' ');
seq_printf(seq, "%s", ss->name);
printed = true;
- }
+ } while_each_subsys_mask();
if (printed)
seq_putc(seq, '\n');
}
-/* show controllers which are currently attached to the default hierarchy */
-static int cgroup_root_controllers_show(struct seq_file *seq, void *v)
-{
- struct cgroup *cgrp = seq_css(seq)->cgroup;
-
- cgroup_print_ss_mask(seq, cgrp->root->subsys_mask &
- ~cgrp_dfl_root_inhibit_ss_mask);
- return 0;
-}
-
/* show controllers which are enabled from the parent */
static int cgroup_controllers_show(struct seq_file *seq, void *v)
{
struct cgroup *cgrp = seq_css(seq)->cgroup;
- cgroup_print_ss_mask(seq, cgroup_parent(cgrp)->subtree_control);
+ cgroup_print_ss_mask(seq, cgroup_control(cgrp));
return 0;
}
* cgroup_update_dfl_csses - update css assoc of a subtree in default hierarchy
* @cgrp: root of the subtree to update csses for
*
- * @cgrp's child_subsys_mask has changed and its subtree's (self excluded)
- * css associations need to be updated accordingly. This function looks up
- * all css_sets which are attached to the subtree, creates the matching
- * updated css_sets and migrates the tasks to the new ones.
+ * @cgrp's control masks have changed and its subtree's css associations
+ * need to be updated accordingly. This function looks up all css_sets
+ * which are attached to the subtree, creates the matching updated css_sets
+ * and migrates the tasks to the new ones.
*/
static int cgroup_update_dfl_csses(struct cgroup *cgrp)
{
LIST_HEAD(preloaded_csets);
struct cgroup_taskset tset = CGROUP_TASKSET_INIT(tset);
- struct cgroup_subsys_state *css;
+ struct cgroup_subsys_state *d_css;
+ struct cgroup *dsct;
struct css_set *src_cset;
int ret;
/* look up all csses currently attached to @cgrp's subtree */
spin_lock_bh(&css_set_lock);
- css_for_each_descendant_pre(css, cgroup_css(cgrp, NULL)) {
+ cgroup_for_each_live_descendant_pre(dsct, d_css, cgrp) {
struct cgrp_cset_link *link;
- /* self is not affected by child_subsys_mask change */
- if (css->cgroup == cgrp)
- continue;
-
- list_for_each_entry(link, &css->cgroup->cset_links, cset_link)
- cgroup_migrate_add_src(link->cset, cgrp,
+ list_for_each_entry(link, &dsct->cset_links, cset_link)
+ cgroup_migrate_add_src(link->cset, dsct,
&preloaded_csets);
}
spin_unlock_bh(&css_set_lock);
/* NULL dst indicates self on default hierarchy */
- ret = cgroup_migrate_prepare_dst(NULL, &preloaded_csets);
+ ret = cgroup_migrate_prepare_dst(&preloaded_csets);
if (ret)
goto out_finish;
}
spin_unlock_bh(&css_set_lock);
- ret = cgroup_taskset_migrate(&tset, cgrp);
+ ret = cgroup_taskset_migrate(&tset, cgrp->root);
out_finish:
cgroup_migrate_finish(&preloaded_csets);
percpu_up_write(&cgroup_threadgroup_rwsem);
return ret;
}
+/**
+ * cgroup_lock_and_drain_offline - lock cgroup_mutex and drain offlined csses
+ * @cgrp: root of the target subtree
+ *
+ * Because css offlining is asynchronous, userland may try to re-enable a
+ * controller while the previous css is still around. This function grabs
+ * cgroup_mutex and drains the previous css instances of @cgrp's subtree.
+ */
+static void cgroup_lock_and_drain_offline(struct cgroup *cgrp)
+ __acquires(&cgroup_mutex)
+{
+ struct cgroup *dsct;
+ struct cgroup_subsys_state *d_css;
+ struct cgroup_subsys *ss;
+ int ssid;
+
+restart:
+ mutex_lock(&cgroup_mutex);
+
+ cgroup_for_each_live_descendant_post(dsct, d_css, cgrp) {
+ for_each_subsys(ss, ssid) {
+ struct cgroup_subsys_state *css = cgroup_css(dsct, ss);
+ DEFINE_WAIT(wait);
+
+ if (!css || !percpu_ref_is_dying(&css->refcnt))
+ continue;
+
+ cgroup_get(dsct);
+ prepare_to_wait(&dsct->offline_waitq, &wait,
+ TASK_UNINTERRUPTIBLE);
+
+ mutex_unlock(&cgroup_mutex);
+ schedule();
+ finish_wait(&dsct->offline_waitq, &wait);
+
+ cgroup_put(dsct);
+ goto restart;
+ }
+ }
+}
+
+/**
+ * cgroup_save_control - save control masks of a subtree
+ * @cgrp: root of the target subtree
+ *
+ * Save ->subtree_control and ->subtree_ss_mask to the respective old_
+ * prefixed fields for @cgrp's subtree including @cgrp itself.
+ */
+static void cgroup_save_control(struct cgroup *cgrp)
+{
+ struct cgroup *dsct;
+ struct cgroup_subsys_state *d_css;
+
+ cgroup_for_each_live_descendant_pre(dsct, d_css, cgrp) {
+ dsct->old_subtree_control = dsct->subtree_control;
+ dsct->old_subtree_ss_mask = dsct->subtree_ss_mask;
+ }
+}
+
+/**
+ * cgroup_propagate_control - refresh control masks of a subtree
+ * @cgrp: root of the target subtree
+ *
+ * For @cgrp and its subtree, ensure ->subtree_ss_mask matches
+ * ->subtree_control and propagate controller availability through the
+ * subtree so that descendants don't have unavailable controllers enabled.
+ */
+static void cgroup_propagate_control(struct cgroup *cgrp)
+{
+ struct cgroup *dsct;
+ struct cgroup_subsys_state *d_css;
+
+ cgroup_for_each_live_descendant_pre(dsct, d_css, cgrp) {
+ dsct->subtree_control &= cgroup_control(dsct);
+ dsct->subtree_ss_mask =
+ cgroup_calc_subtree_ss_mask(dsct->subtree_control,
+ cgroup_ss_mask(dsct));
+ }
+}
+
+/**
+ * cgroup_restore_control - restore control masks of a subtree
+ * @cgrp: root of the target subtree
+ *
+ * Restore ->subtree_control and ->subtree_ss_mask from the respective old_
+ * prefixed fields for @cgrp's subtree including @cgrp itself.
+ */
+static void cgroup_restore_control(struct cgroup *cgrp)
+{
+ struct cgroup *dsct;
+ struct cgroup_subsys_state *d_css;
+
+ cgroup_for_each_live_descendant_post(dsct, d_css, cgrp) {
+ dsct->subtree_control = dsct->old_subtree_control;
+ dsct->subtree_ss_mask = dsct->old_subtree_ss_mask;
+ }
+}
+
+static bool css_visible(struct cgroup_subsys_state *css)
+{
+ struct cgroup_subsys *ss = css->ss;
+ struct cgroup *cgrp = css->cgroup;
+
+ if (cgroup_control(cgrp) & (1 << ss->id))
+ return true;
+ if (!(cgroup_ss_mask(cgrp) & (1 << ss->id)))
+ return false;
+ return cgroup_on_dfl(cgrp) && ss->implicit_on_dfl;
+}
+
+/**
+ * cgroup_apply_control_enable - enable or show csses according to control
+ * @cgrp: root of the target subtree
+ *
+ * Walk @cgrp's subtree and create new csses or make the existing ones
+ * visible. A css is created invisible if it's being implicitly enabled
+ * through dependency. An invisible css is made visible when the userland
+ * explicitly enables it.
+ *
+ * Returns 0 on success, -errno on failure. On failure, csses which have
+ * been processed already aren't cleaned up. The caller is responsible for
+ * cleaning up with cgroup_apply_control_disble().
+ */
+static int cgroup_apply_control_enable(struct cgroup *cgrp)
+{
+ struct cgroup *dsct;
+ struct cgroup_subsys_state *d_css;
+ struct cgroup_subsys *ss;
+ int ssid, ret;
+
+ cgroup_for_each_live_descendant_pre(dsct, d_css, cgrp) {
+ for_each_subsys(ss, ssid) {
+ struct cgroup_subsys_state *css = cgroup_css(dsct, ss);
+
+ WARN_ON_ONCE(css && percpu_ref_is_dying(&css->refcnt));
+
+ if (!(cgroup_ss_mask(dsct) & (1 << ss->id)))
+ continue;
+
+ if (!css) {
+ css = css_create(dsct, ss);
+ if (IS_ERR(css))
+ return PTR_ERR(css);
+ }
+
+ if (css_visible(css)) {
+ ret = css_populate_dir(css);
+ if (ret)
+ return ret;
+ }
+ }
+ }
+
+ return 0;
+}
+
+/**
+ * cgroup_apply_control_disable - kill or hide csses according to control
+ * @cgrp: root of the target subtree
+ *
+ * Walk @cgrp's subtree and kill and hide csses so that they match
+ * cgroup_ss_mask() and cgroup_visible_mask().
+ *
+ * A css is hidden when the userland requests it to be disabled while other
+ * subsystems are still depending on it. The css must not actively control
+ * resources and be in the vanilla state if it's made visible again later.
+ * Controllers which may be depended upon should provide ->css_reset() for
+ * this purpose.
+ */
+static void cgroup_apply_control_disable(struct cgroup *cgrp)
+{
+ struct cgroup *dsct;
+ struct cgroup_subsys_state *d_css;
+ struct cgroup_subsys *ss;
+ int ssid;
+
+ cgroup_for_each_live_descendant_post(dsct, d_css, cgrp) {
+ for_each_subsys(ss, ssid) {
+ struct cgroup_subsys_state *css = cgroup_css(dsct, ss);
+
+ WARN_ON_ONCE(css && percpu_ref_is_dying(&css->refcnt));
+
+ if (!css)
+ continue;
+
+ if (css->parent &&
+ !(cgroup_ss_mask(dsct) & (1 << ss->id))) {
+ kill_css(css);
+ } else if (!css_visible(css)) {
+ css_clear_dir(css);
+ if (ss->css_reset)
+ ss->css_reset(css);
+ }
+ }
+ }
+}
+
+/**
+ * cgroup_apply_control - apply control mask updates to the subtree
+ * @cgrp: root of the target subtree
+ *
+ * subsystems can be enabled and disabled in a subtree using the following
+ * steps.
+ *
+ * 1. Call cgroup_save_control() to stash the current state.
+ * 2. Update ->subtree_control masks in the subtree as desired.
+ * 3. Call cgroup_apply_control() to apply the changes.
+ * 4. Optionally perform other related operations.
+ * 5. Call cgroup_finalize_control() to finish up.
+ *
+ * This function implements step 3 and propagates the mask changes
+ * throughout @cgrp's subtree, updates csses accordingly and perform
+ * process migrations.
+ */
+static int cgroup_apply_control(struct cgroup *cgrp)
+{
+ int ret;
+
+ cgroup_propagate_control(cgrp);
+
+ ret = cgroup_apply_control_enable(cgrp);
+ if (ret)
+ return ret;
+
+ /*
+ * At this point, cgroup_e_css() results reflect the new csses
+ * making the following cgroup_update_dfl_csses() properly update
+ * css associations of all tasks in the subtree.
+ */
+ ret = cgroup_update_dfl_csses(cgrp);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+/**
+ * cgroup_finalize_control - finalize control mask update
+ * @cgrp: root of the target subtree
+ * @ret: the result of the update
+ *
+ * Finalize control mask update. See cgroup_apply_control() for more info.
+ */
+static void cgroup_finalize_control(struct cgroup *cgrp, int ret)
+{
+ if (ret) {
+ cgroup_restore_control(cgrp);
+ cgroup_propagate_control(cgrp);
+ }
+
+ cgroup_apply_control_disable(cgrp);
+}
+
/* change the enabled child controllers for a cgroup in the default hierarchy */
static ssize_t cgroup_subtree_control_write(struct kernfs_open_file *of,
char *buf, size_t nbytes,
loff_t off)
{
- unsigned long enable = 0, disable = 0;
- unsigned long css_enable, css_disable, old_sc, new_sc, old_ss, new_ss;
+ u16 enable = 0, disable = 0;
struct cgroup *cgrp, *child;
struct cgroup_subsys *ss;
char *tok;
*/
buf = strstrip(buf);
while ((tok = strsep(&buf, " "))) {
- unsigned long tmp_ss_mask = ~cgrp_dfl_root_inhibit_ss_mask;
-
if (tok[0] == '\0')
continue;
- for_each_subsys_which(ss, ssid, &tmp_ss_mask) {
+ do_each_subsys_mask(ss, ssid, ~cgrp_dfl_inhibit_ss_mask) {
if (!cgroup_ssid_enabled(ssid) ||
strcmp(tok + 1, ss->name))
continue;
return -EINVAL;
}
break;
- }
+ } while_each_subsys_mask();
if (ssid == CGROUP_SUBSYS_COUNT)
return -EINVAL;
}
- cgrp = cgroup_kn_lock_live(of->kn);
+ cgrp = cgroup_kn_lock_live(of->kn, true);
if (!cgrp)
return -ENODEV;
continue;
}
- /* unavailable or not enabled on the parent? */
- if (!(cgrp_dfl_root.subsys_mask & (1 << ssid)) ||
- (cgroup_parent(cgrp) &&
- !(cgroup_parent(cgrp)->subtree_control & (1 << ssid)))) {
+ if (!(cgroup_control(cgrp) & (1 << ssid))) {
ret = -ENOENT;
goto out_unlock;
}
goto out_unlock;
}
- /*
- * Update subsys masks and calculate what needs to be done. More
- * subsystems than specified may need to be enabled or disabled
- * depending on subsystem dependencies.
- */
- old_sc = cgrp->subtree_control;
- old_ss = cgrp->child_subsys_mask;
- new_sc = (old_sc | enable) & ~disable;
- new_ss = cgroup_calc_child_subsys_mask(cgrp, new_sc);
-
- css_enable = ~old_ss & new_ss;
- css_disable = old_ss & ~new_ss;
- enable |= css_enable;
- disable |= css_disable;
-
- /*
- * Because css offlining is asynchronous, userland might try to
- * re-enable the same controller while the previous instance is
- * still around. In such cases, wait till it's gone using
- * offline_waitq.
- */
- for_each_subsys_which(ss, ssid, &css_enable) {
- cgroup_for_each_live_child(child, cgrp) {
- DEFINE_WAIT(wait);
-
- if (!cgroup_css(child, ss))
- continue;
-
- cgroup_get(child);
- prepare_to_wait(&child->offline_waitq, &wait,
- TASK_UNINTERRUPTIBLE);
- cgroup_kn_unlock(of->kn);
- schedule();
- finish_wait(&child->offline_waitq, &wait);
- cgroup_put(child);
-
- return restart_syscall();
- }
- }
-
- cgrp->subtree_control = new_sc;
- cgrp->child_subsys_mask = new_ss;
-
- /*
- * Create new csses or make the existing ones visible. A css is
- * created invisible if it's being implicitly enabled through
- * dependency. An invisible css is made visible when the userland
- * explicitly enables it.
- */
- for_each_subsys(ss, ssid) {
- if (!(enable & (1 << ssid)))
- continue;
-
- cgroup_for_each_live_child(child, cgrp) {
- if (css_enable & (1 << ssid))
- ret = create_css(child, ss,
- cgrp->subtree_control & (1 << ssid));
- else
- ret = css_populate_dir(cgroup_css(child, ss),
- NULL);
- if (ret)
- goto err_undo_css;
- }
- }
-
- /*
- * At this point, cgroup_e_css() results reflect the new csses
- * making the following cgroup_update_dfl_csses() properly update
- * css associations of all tasks in the subtree.
- */
- ret = cgroup_update_dfl_csses(cgrp);
- if (ret)
- goto err_undo_css;
+ /* save and update control masks and prepare csses */
+ cgroup_save_control(cgrp);
- /*
- * All tasks are migrated out of disabled csses. Kill or hide
- * them. A css is hidden when the userland requests it to be
- * disabled while other subsystems are still depending on it. The
- * css must not actively control resources and be in the vanilla
- * state if it's made visible again later. Controllers which may
- * be depended upon should provide ->css_reset() for this purpose.
- */
- for_each_subsys(ss, ssid) {
- if (!(disable & (1 << ssid)))
- continue;
+ cgrp->subtree_control |= enable;
+ cgrp->subtree_control &= ~disable;
- cgroup_for_each_live_child(child, cgrp) {
- struct cgroup_subsys_state *css = cgroup_css(child, ss);
+ ret = cgroup_apply_control(cgrp);
- if (css_disable & (1 << ssid)) {
- kill_css(css);
- } else {
- css_clear_dir(css, NULL);
- if (ss->css_reset)
- ss->css_reset(css);
- }
- }
- }
-
- /*
- * The effective csses of all the descendants (excluding @cgrp) may
- * have changed. Subsystems can optionally subscribe to this event
- * by implementing ->css_e_css_changed() which is invoked if any of
- * the effective csses seen from the css's cgroup may have changed.
- */
- for_each_subsys(ss, ssid) {
- struct cgroup_subsys_state *this_css = cgroup_css(cgrp, ss);
- struct cgroup_subsys_state *css;
-
- if (!ss->css_e_css_changed || !this_css)
- continue;
-
- css_for_each_descendant_pre(css, this_css)
- if (css != this_css)
- ss->css_e_css_changed(css);
- }
+ cgroup_finalize_control(cgrp, ret);
kernfs_activate(cgrp->kn);
ret = 0;
out_unlock:
cgroup_kn_unlock(of->kn);
return ret ?: nbytes;
-
-err_undo_css:
- cgrp->subtree_control = old_sc;
- cgrp->child_subsys_mask = old_ss;
-
- for_each_subsys(ss, ssid) {
- if (!(enable & (1 << ssid)))
- continue;
-
- cgroup_for_each_live_child(child, cgrp) {
- struct cgroup_subsys_state *css = cgroup_css(child, ss);
-
- if (!css)
- continue;
-
- if (css_enable & (1 << ssid))
- kill_css(css);
- else
- css_clear_dir(css, NULL);
- }
- }
- goto out_unlock;
}
static int cgroup_events_show(struct seq_file *seq, void *v)
bool is_add)
{
struct cftype *cft, *cft_end = NULL;
- int ret;
+ int ret = 0;
lockdep_assert_held(&cgroup_mutex);
cgroup_rm_file(cgrp, cft);
}
}
- return 0;
+ return ret;
}
static int cgroup_apply_cftypes(struct cftype *cfts, bool is_add)
css_for_each_descendant_pre(css, cgroup_css(root, ss)) {
struct cgroup *cgrp = css->cgroup;
- if (cgroup_is_dead(cgrp))
+ if (!(css->flags & CSS_VISIBLE))
continue;
ret = cgroup_addrm_files(css, cgrp, cfts, is_add);
struct task_struct *task;
int ret;
+ if (!cgroup_may_migrate_to(to))
+ return -EBUSY;
+
mutex_lock(&cgroup_mutex);
/* all tasks in @from are being moved, all csets are source */
cgroup_migrate_add_src(link->cset, to, &preloaded_csets);
spin_unlock_bh(&css_set_lock);
- ret = cgroup_migrate_prepare_dst(to, &preloaded_csets);
+ ret = cgroup_migrate_prepare_dst(&preloaded_csets);
if (ret)
goto out_err;
css_task_iter_end(&it);
if (task) {
- ret = cgroup_migrate(task, false, to);
+ ret = cgroup_migrate(task, false, to->root);
put_task_struct(task);
}
} while (task && !ret);
},
{
.name = "cgroup.controllers",
- .flags = CFTYPE_ONLY_ON_ROOT,
- .seq_show = cgroup_root_controllers_show,
- },
- {
- .name = "cgroup.controllers",
- .flags = CFTYPE_NOT_ON_ROOT,
.seq_show = cgroup_controllers_show,
},
{
* Those are supported by RCU protecting clearing of
* cgrp->kn->priv backpointer.
*/
- RCU_INIT_POINTER(*(void __rcu __force **)&cgrp->kn->priv, NULL);
+ if (cgrp->kn)
+ RCU_INIT_POINTER(*(void __rcu __force **)&cgrp->kn->priv,
+ NULL);
}
mutex_unlock(&cgroup_mutex);
if (!(css->flags & CSS_ONLINE))
return;
+ if (ss->css_reset)
+ ss->css_reset(css);
+
if (ss->css_offline)
ss->css_offline(css);
}
/**
- * create_css - create a cgroup_subsys_state
+ * css_create - create a cgroup_subsys_state
* @cgrp: the cgroup new css will be associated with
* @ss: the subsys of new css
- * @visible: whether to create control knobs for the new css or not
*
* Create a new css associated with @cgrp - @ss pair. On success, the new
- * css is online and installed in @cgrp with all interface files created if
- * @visible. Returns 0 on success, -errno on failure.
+ * css is online and installed in @cgrp. This function doesn't create the
+ * interface files. Returns 0 on success, -errno on failure.
*/
-static int create_css(struct cgroup *cgrp, struct cgroup_subsys *ss,
- bool visible)
+static struct cgroup_subsys_state *css_create(struct cgroup *cgrp,
+ struct cgroup_subsys *ss)
{
struct cgroup *parent = cgroup_parent(cgrp);
struct cgroup_subsys_state *parent_css = cgroup_css(parent, ss);
css = ss->css_alloc(parent_css);
if (IS_ERR(css))
- return PTR_ERR(css);
+ return css;
init_and_link_css(css, ss, cgrp);
goto err_free_percpu_ref;
css->id = err;
- if (visible) {
- err = css_populate_dir(css, NULL);
- if (err)
- goto err_free_id;
- }
-
/* @css is ready to be brought online now, make it visible */
list_add_tail_rcu(&css->sibling, &parent_css->children);
cgroup_idr_replace(&ss->css_idr, css, css->id);
ss->warned_broken_hierarchy = true;
}
- return 0;
+ return css;
err_list_del:
list_del_rcu(&css->sibling);
- css_clear_dir(css, NULL);
-err_free_id:
cgroup_idr_remove(&ss->css_idr, css->id);
err_free_percpu_ref:
percpu_ref_exit(&css->refcnt);
err_free_css:
call_rcu(&css->rcu_head, css_free_rcu_fn);
- return err;
+ return ERR_PTR(err);
}
-static int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name,
- umode_t mode)
+static struct cgroup *cgroup_create(struct cgroup *parent)
{
- struct cgroup *parent, *cgrp, *tcgrp;
- struct cgroup_root *root;
- struct cgroup_subsys *ss;
- struct kernfs_node *kn;
- int level, ssid, ret;
-
- /* Do not accept '\n' to prevent making /proc/<pid>/cgroup unparsable.
- */
- if (strchr(name, '\n'))
- return -EINVAL;
-
- parent = cgroup_kn_lock_live(parent_kn);
- if (!parent)
- return -ENODEV;
- root = parent->root;
- level = parent->level + 1;
+ struct cgroup_root *root = parent->root;
+ struct cgroup *cgrp, *tcgrp;
+ int level = parent->level + 1;
+ int ret;
/* allocate the cgroup and its ID, 0 is reserved for the root */
cgrp = kzalloc(sizeof(*cgrp) +
sizeof(cgrp->ancestor_ids[0]) * (level + 1), GFP_KERNEL);
- if (!cgrp) {
- ret = -ENOMEM;
- goto out_unlock;
- }
+ if (!cgrp)
+ return ERR_PTR(-ENOMEM);
ret = percpu_ref_init(&cgrp->self.refcnt, css_release, 0, GFP_KERNEL);
if (ret)
if (test_bit(CGRP_CPUSET_CLONE_CHILDREN, &parent->flags))
set_bit(CGRP_CPUSET_CLONE_CHILDREN, &cgrp->flags);
- /* create the directory */
- kn = kernfs_create_dir(parent->kn, name, mode, cgrp);
- if (IS_ERR(kn)) {
- ret = PTR_ERR(kn);
- goto out_free_id;
- }
- cgrp->kn = kn;
-
- /*
- * This extra ref will be put in cgroup_free_fn() and guarantees
- * that @cgrp->kn is always accessible.
- */
- kernfs_get(kn);
-
cgrp->self.serial_nr = css_serial_nr_next++;
/* allocation complete, commit to creation */
*/
cgroup_idr_replace(&root->cgroup_idr, cgrp, cgrp->id);
- ret = cgroup_kn_set_ugid(kn);
- if (ret)
- goto out_destroy;
+ /*
+ * On the default hierarchy, a child doesn't automatically inherit
+ * subtree_control from the parent. Each is configured manually.
+ */
+ if (!cgroup_on_dfl(cgrp))
+ cgrp->subtree_control = cgroup_control(cgrp);
- ret = css_populate_dir(&cgrp->self, NULL);
+ cgroup_propagate_control(cgrp);
+
+ /* @cgrp doesn't have dir yet so the following will only create csses */
+ ret = cgroup_apply_control_enable(cgrp);
if (ret)
goto out_destroy;
- /* let's create and online css's */
- for_each_subsys(ss, ssid) {
- if (parent->child_subsys_mask & (1 << ssid)) {
- ret = create_css(cgrp, ss,
- parent->subtree_control & (1 << ssid));
- if (ret)
- goto out_destroy;
- }
+ return cgrp;
+
+out_cancel_ref:
+ percpu_ref_exit(&cgrp->self.refcnt);
+out_free_cgrp:
+ kfree(cgrp);
+ return ERR_PTR(ret);
+out_destroy:
+ cgroup_destroy_locked(cgrp);
+ return ERR_PTR(ret);
+}
+
+static int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name,
+ umode_t mode)
+{
+ struct cgroup *parent, *cgrp;
+ struct kernfs_node *kn;
+ int ret;
+
+ /* do not accept '\n' to prevent making /proc/<pid>/cgroup unparsable */
+ if (strchr(name, '\n'))
+ return -EINVAL;
+
+ parent = cgroup_kn_lock_live(parent_kn, false);
+ if (!parent)
+ return -ENODEV;
+
+ cgrp = cgroup_create(parent);
+ if (IS_ERR(cgrp)) {
+ ret = PTR_ERR(cgrp);
+ goto out_unlock;
+ }
+
+ /* create the directory */
+ kn = kernfs_create_dir(parent->kn, name, mode, cgrp);
+ if (IS_ERR(kn)) {
+ ret = PTR_ERR(kn);
+ goto out_destroy;
}
+ cgrp->kn = kn;
/*
- * On the default hierarchy, a child doesn't automatically inherit
- * subtree_control from the parent. Each is configured manually.
+ * This extra ref will be put in cgroup_free_fn() and guarantees
+ * that @cgrp->kn is always accessible.
*/
- if (!cgroup_on_dfl(cgrp)) {
- cgrp->subtree_control = parent->subtree_control;
- cgroup_refresh_child_subsys_mask(cgrp);
- }
+ kernfs_get(kn);
+
+ ret = cgroup_kn_set_ugid(kn);
+ if (ret)
+ goto out_destroy;
+
+ ret = css_populate_dir(&cgrp->self);
+ if (ret)
+ goto out_destroy;
+ ret = cgroup_apply_control_enable(cgrp);
+ if (ret)
+ goto out_destroy;
+
+ /* let's create and online css's */
kernfs_activate(kn);
ret = 0;
goto out_unlock;
-out_free_id:
- cgroup_idr_remove(&root->cgroup_idr, cgrp->id);
-out_cancel_ref:
- percpu_ref_exit(&cgrp->self.refcnt);
-out_free_cgrp:
- kfree(cgrp);
+out_destroy:
+ cgroup_destroy_locked(cgrp);
out_unlock:
cgroup_kn_unlock(parent_kn);
return ret;
-
-out_destroy:
- cgroup_destroy_locked(cgrp);
- goto out_unlock;
}
/*
* This must happen before css is disassociated with its cgroup.
* See seq_css() for details.
*/
- css_clear_dir(css, NULL);
+ css_clear_dir(css);
/*
* Killing would put the base ref, but we need to keep it alive
__releases(&cgroup_mutex) __acquires(&cgroup_mutex)
{
struct cgroup_subsys_state *css;
+ struct cgrp_cset_link *link;
int ssid;
lockdep_assert_held(&cgroup_mutex);
return -EBUSY;
/*
- * Mark @cgrp dead. This prevents further task migration and child
- * creation by disabling cgroup_lock_live_group().
+ * Mark @cgrp and the associated csets dead. The former prevents
+ * further task migration and child creation by disabling
+ * cgroup_lock_live_group(). The latter makes the csets ignored by
+ * the migration path.
*/
cgrp->self.flags &= ~CSS_ONLINE;
+ spin_lock_bh(&css_set_lock);
+ list_for_each_entry(link, &cgrp->cset_links, cset_link)
+ link->cset->dead = true;
+ spin_unlock_bh(&css_set_lock);
+
/* initiate massacre of all css's */
for_each_css(css, ssid, cgrp)
kill_css(css);
struct cgroup *cgrp;
int ret = 0;
- cgrp = cgroup_kn_lock_live(kn);
+ cgrp = cgroup_kn_lock_live(kn, false);
if (!cgrp)
return 0;
for_each_subsys(ss, i) {
WARN(!ss->css_alloc || !ss->css_free || ss->name || ss->id,
- "invalid cgroup_subsys %d:%s css_alloc=%p css_free=%p name:id=%d:%s\n",
+ "invalid cgroup_subsys %d:%s css_alloc=%p css_free=%p id:name=%d:%s\n",
i, cgroup_subsys_name[i], ss->css_alloc, ss->css_free,
ss->id, ss->name);
WARN(strlen(cgroup_subsys_name[i]) > MAX_CGROUP_TYPE_NAMELEN,
return 0;
}
-static unsigned long cgroup_disable_mask __initdata;
+static u16 cgroup_disable_mask __initdata;
/**
* cgroup_init - cgroup initialization
int __init cgroup_init(void)
{
struct cgroup_subsys *ss;
- unsigned long key;
int ssid;
+ BUILD_BUG_ON(CGROUP_SUBSYS_COUNT > 16);
BUG_ON(percpu_init_rwsem(&cgroup_threadgroup_rwsem));
BUG_ON(cgroup_init_cftypes(NULL, cgroup_dfl_base_files));
BUG_ON(cgroup_init_cftypes(NULL, cgroup_legacy_base_files));
mutex_lock(&cgroup_mutex);
- /* Add init_css_set to the hash table */
- key = css_set_hash(init_css_set.subsys);
- hash_add(css_set_table, &init_css_set.hlist, key);
+ /*
+ * Add init_css_set to the hash table so that dfl_root can link to
+ * it during init.
+ */
+ hash_add(css_set_table, &init_css_set.hlist,
+ css_set_hash(init_css_set.subsys));
BUG_ON(cgroup_setup_root(&cgrp_dfl_root, 0));
continue;
}
+ if (cgroup_ssid_no_v1(ssid))
+ printk(KERN_INFO "Disabling %s control group subsystem in v1 mounts\n",
+ ss->name);
+
cgrp_dfl_root.subsys_mask |= 1 << ss->id;
- if (!ss->dfl_cftypes)
- cgrp_dfl_root_inhibit_ss_mask |= 1 << ss->id;
+ if (ss->implicit_on_dfl)
+ cgrp_dfl_implicit_ss_mask |= 1 << ss->id;
+ else if (!ss->dfl_cftypes)
+ cgrp_dfl_inhibit_ss_mask |= 1 << ss->id;
if (ss->dfl_cftypes == ss->legacy_cftypes) {
WARN_ON(cgroup_add_cftypes(ss, ss->dfl_cftypes));
ss->bind(init_css_set.subsys[ssid]);
}
+ /* init_css_set.subsys[] has been updated, re-hash */
+ hash_del(&init_css_set.hlist);
+ hash_add(css_set_table, &init_css_set.hlist,
+ css_set_hash(init_css_set.subsys));
+
WARN_ON(sysfs_create_mount_point(fs_kobj, "cgroup"));
WARN_ON(register_filesystem(&cgroup_fs_type));
WARN_ON(register_filesystem(&cgroup2_fs_type));
struct cgroup *cgrp;
int ssid, count = 0;
- if (root == &cgrp_dfl_root && !cgrp_dfl_root_visible)
+ if (root == &cgrp_dfl_root && !cgrp_dfl_visible)
continue;
seq_printf(m, "%d:", root->hierarchy_id);
struct cgroup_subsys *ss;
int i, j, ret;
- for_each_subsys_which(ss, i, &have_canfork_callback) {
+ do_each_subsys_mask(ss, i, have_canfork_callback) {
ret = ss->can_fork(child);
if (ret)
goto out_revert;
- }
+ } while_each_subsys_mask();
return 0;
* css_set; otherwise, @child might change state between ->fork()
* and addition to css_set.
*/
- for_each_subsys_which(ss, i, &have_fork_callback)
+ do_each_subsys_mask(ss, i, have_fork_callback) {
ss->fork(child);
+ } while_each_subsys_mask();
}
/**
}
/* see cgroup_post_fork() for details */
- for_each_subsys_which(ss, i, &have_exit_callback)
+ do_each_subsys_mask(ss, i, have_exit_callback) {
ss->exit(tsk);
+ } while_each_subsys_mask();
}
void cgroup_free(struct task_struct *task)
struct cgroup_subsys *ss;
int ssid;
- for_each_subsys_which(ss, ssid, &have_free_callback)
+ do_each_subsys_mask(ss, ssid, have_free_callback) {
ss->free(task);
+ } while_each_subsys_mask();
put_css_set(cset);
}
}
__setup("cgroup_disable=", cgroup_disable);
+static int __init cgroup_no_v1(char *str)
+{
+ struct cgroup_subsys *ss;
+ char *token;
+ int i;
+
+ while ((token = strsep(&str, ",")) != NULL) {
+ if (!*token)
+ continue;
+
+ if (!strcmp(token, "all")) {
+ cgroup_no_v1_mask = U16_MAX;
+ break;
+ }
+
+ for_each_subsys(ss, i) {
+ if (strcmp(token, ss->name) &&
+ strcmp(token, ss->legacy_name))
+ continue;
+
+ cgroup_no_v1_mask |= 1 << i;
+ }
+ }
+ return 1;
+}
+__setup("cgroup_no_v1=", cgroup_no_v1);
+
/**
* css_tryget_online_from_dir - get corresponding css from a cgroup dentry
* @dentry: directory dentry of interest
struct cgroup_subsys *ss)
{
struct kernfs_node *kn = kernfs_node_from_dentry(dentry);
+ struct file_system_type *s_type = dentry->d_sb->s_type;
struct cgroup_subsys_state *css = NULL;
struct cgroup *cgrp;
/* is @dentry a cgroup dir? */
- if (dentry->d_sb->s_type != &cgroup_fs_type || !kn ||
- kernfs_type(kn) != KERNFS_DIR)
+ if ((s_type != &cgroup_fs_type && s_type != &cgroup2_fs_type) ||
+ !kn || kernfs_type(kn) != KERNFS_DIR)
return ERR_PTR(-EBADF);
rcu_read_lock();
projects / cascardo / linux.git / commitdiff