summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--Documentation/cgroup-v2.txt221
-rw-r--r--include/linux/cgroup-defs.h68
-rw-r--r--include/linux/cgroup.h39
-rw-r--r--kernel/cgroup/cgroup-internal.h12
-rw-r--r--kernel/cgroup/cgroup-v1.c75
-rw-r--r--kernel/cgroup/cgroup.c947
-rw-r--r--kernel/cgroup/cpuset.c39
-rw-r--r--kernel/cgroup/debug.c53
-rw-r--r--kernel/cgroup/freezer.c6
-rw-r--r--kernel/cgroup/pids.c1
-rw-r--r--kernel/events/core.c1
-rw-r--r--mm/memcontrol.c2
-rw-r--r--net/core/netclassid_cgroup.c2
13 files changed, 1194 insertions, 272 deletions
diff --git a/Documentation/cgroup-v2.txt b/Documentation/cgroup-v2.txt
index bde177103567..dc44785dc0fa 100644
--- a/Documentation/cgroup-v2.txt
+++ b/Documentation/cgroup-v2.txt
@@ -18,7 +18,9 @@ v1 is available under Documentation/cgroup-v1/.
1-2. What is cgroup?
2. Basic Operations
2-1. Mounting
- 2-2. Organizing Processes
+ 2-2. Organizing Processes and Threads
+ 2-2-1. Processes
+ 2-2-2. Threads
2-3. [Un]populated Notification
2-4. Controlling Controllers
2-4-1. Enabling and Disabling
@@ -167,8 +169,11 @@ cgroup v2 currently supports the following mount options.
Delegation section for details.
-Organizing Processes
---------------------
+Organizing Processes and Threads
+--------------------------------
+
+Processes
+~~~~~~~~~
Initially, only the root cgroup exists to which all processes belong.
A child cgroup can be created by creating a sub-directory::
@@ -219,6 +224,105 @@ is removed subsequently, " (deleted)" is appended to the path::
0::/test-cgroup/test-cgroup-nested (deleted)
+Threads
+~~~~~~~
+
+cgroup v2 supports thread granularity for a subset of controllers to
+support use cases requiring hierarchical resource distribution across
+the threads of a group of processes. By default, all threads of a
+process belong to the same cgroup, which also serves as the resource
+domain to host resource consumptions which are not specific to a
+process or thread. The thread mode allows threads to be spread across
+a subtree while still maintaining the common resource domain for them.
+
+Controllers which support thread mode are called threaded controllers.
+The ones which don't are called domain controllers.
+
+Marking a cgroup threaded makes it join the resource domain of its
+parent as a threaded cgroup. The parent may be another threaded
+cgroup whose resource domain is further up in the hierarchy. The root
+of a threaded subtree, that is, the nearest ancestor which is not
+threaded, is called threaded domain or thread root interchangeably and
+serves as the resource domain for the entire subtree.
+
+Inside a threaded subtree, threads of a process can be put in
+different cgroups and are not subject to the no internal process
+constraint - threaded controllers can be enabled on non-leaf cgroups
+whether they have threads in them or not.
+
+As the threaded domain cgroup hosts all the domain resource
+consumptions of the subtree, it is considered to have internal
+resource consumptions whether there are processes in it or not and
+can't have populated child cgroups which aren't threaded. Because the
+root cgroup is not subject to no internal process constraint, it can
+serve both as a threaded domain and a parent to domain cgroups.
+
+The current operation mode or type of the cgroup is shown in the
+"cgroup.type" file which indicates whether the cgroup is a normal
+domain, a domain which is serving as the domain of a threaded subtree,
+or a threaded cgroup.
+
+On creation, a cgroup is always a domain cgroup and can be made
+threaded by writing "threaded" to the "cgroup.type" file. The
+operation is single direction::
+
+ # echo threaded > cgroup.type
+
+Once threaded, the cgroup can't be made a domain again. To enable the
+thread mode, the following conditions must be met.
+
+- As the cgroup will join the parent's resource domain. The parent
+ must either be a valid (threaded) domain or a threaded cgroup.
+
+- When the parent is an unthreaded domain, it must not have any domain
+ controllers enabled or populated domain children. The root is
+ exempt from this requirement.
+
+Topology-wise, a cgroup can be in an invalid state. Please consider
+the following toplogy::
+
+ A (threaded domain) - B (threaded) - C (domain, just created)
+
+C is created as a domain but isn't connected to a parent which can
+host child domains. C can't be used until it is turned into a
+threaded cgroup. "cgroup.type" file will report "domain (invalid)" in
+these cases. Operations which fail due to invalid topology use
+EOPNOTSUPP as the errno.
+
+A domain cgroup is turned into a threaded domain when one of its child
+cgroup becomes threaded or threaded controllers are enabled in the
+"cgroup.subtree_control" file while there are processes in the cgroup.
+A threaded domain reverts to a normal domain when the conditions
+clear.
+
+When read, "cgroup.threads" contains the list of the thread IDs of all
+threads in the cgroup. Except that the operations are per-thread
+instead of per-process, "cgroup.threads" has the same format and
+behaves the same way as "cgroup.procs". While "cgroup.threads" can be
+written to in any cgroup, as it can only move threads inside the same
+threaded domain, its operations are confined inside each threaded
+subtree.
+
+The threaded domain cgroup serves as the resource domain for the whole
+subtree, and, while the threads can be scattered across the subtree,
+all the processes are considered to be in the threaded domain cgroup.
+"cgroup.procs" in a threaded domain cgroup contains the PIDs of all
+processes in the subtree and is not readable in the subtree proper.
+However, "cgroup.procs" can be written to from anywhere in the subtree
+to migrate all threads of the matching process to the cgroup.
+
+Only threaded controllers can be enabled in a threaded subtree. When
+a threaded controller is enabled inside a threaded subtree, it only
+accounts for and controls resource consumptions associated with the
+threads in the cgroup and its descendants. All consumptions which
+aren't tied to a specific thread belong to the threaded domain cgroup.
+
+Because a threaded subtree is exempt from no internal process
+constraint, a threaded controller must be able to handle competition
+between threads in a non-leaf cgroup and its child cgroups. Each
+threaded controller defines how such competitions are handled.
+
+
[Un]populated Notification
--------------------------
@@ -302,15 +406,15 @@ disabled if one or more children have it enabled.
No Internal Process Constraint
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-Non-root cgroups can only distribute resources to their children when
-they don't have any processes of their own. In other words, only
-cgroups which don't contain any processes can have controllers enabled
-in their "cgroup.subtree_control" files.
+Non-root cgroups can distribute domain resources to their children
+only when they don't have any processes of their own. In other words,
+only domain cgroups which don't contain any processes can have domain
+controllers enabled in their "cgroup.subtree_control" files.
-This guarantees that, when a controller is looking at the part of the
-hierarchy which has it enabled, processes are always only on the
-leaves. This rules out situations where child cgroups compete against
-internal processes of the parent.
+This guarantees that, when a domain controller is looking at the part
+of the hierarchy which has it enabled, processes are always only on
+the leaves. This rules out situations where child cgroups compete
+against internal processes of the parent.
The root cgroup is exempt from this restriction. Root contains
processes and anonymous resource consumption which can't be associated
@@ -334,10 +438,10 @@ Model of Delegation
~~~~~~~~~~~~~~~~~~~
A cgroup can be delegated in two ways. First, to a less privileged
-user by granting write access of the directory and its "cgroup.procs"
-and "cgroup.subtree_control" files to the user. Second, if the
-"nsdelegate" mount option is set, automatically to a cgroup namespace
-on namespace creation.
+user by granting write access of the directory and its "cgroup.procs",
+"cgroup.threads" and "cgroup.subtree_control" files to the user.
+Second, if the "nsdelegate" mount option is set, automatically to a
+cgroup namespace on namespace creation.
Because the resource control interface files in a given directory
control the distribution of the parent's resources, the delegatee
@@ -644,6 +748,29 @@ Core Interface Files
All cgroup core files are prefixed with "cgroup."
+ cgroup.type
+
+ A read-write single value file which exists on non-root
+ cgroups.
+
+ When read, it indicates the current type of the cgroup, which
+ can be one of the following values.
+
+ - "domain" : A normal valid domain cgroup.
+
+ - "domain threaded" : A threaded domain cgroup which is
+ serving as the root of a threaded subtree.
+
+ - "domain invalid" : A cgroup which is in an invalid state.
+ It can't be populated or have controllers enabled. It may
+ be allowed to become a threaded cgroup.
+
+ - "threaded" : A threaded cgroup which is a member of a
+ threaded subtree.
+
+ A cgroup can be turned into a threaded cgroup by writing
+ "threaded" to this file.
+
cgroup.procs
A read-write new-line separated values file which exists on
all cgroups.
@@ -658,9 +785,6 @@ All cgroup core files are prefixed with "cgroup."
the PID to the cgroup. The writer should match all of the
following conditions.
- - Its euid is either root or must match either uid or suid of
- the target process.
-
- It must have write access to the "cgroup.procs" file.
- It must have write access to the "cgroup.procs" file of the
@@ -669,6 +793,35 @@ All cgroup core files are prefixed with "cgroup."
When delegating a sub-hierarchy, write access to this file
should be granted along with the containing directory.
+ In a threaded cgroup, reading this file fails with EOPNOTSUPP
+ as all the processes belong to the thread root. Writing is
+ supported and moves every thread of the process to the cgroup.
+
+ cgroup.threads
+ A read-write new-line separated values file which exists on
+ all cgroups.
+
+ When read, it lists the TIDs of all threads which belong to
+ the cgroup one-per-line. The TIDs are not ordered and the
+ same TID may show up more than once if the thread got moved to
+ another cgroup and then back or the TID got recycled while
+ reading.
+
+ A TID can be written to migrate the thread associated with the
+ TID to the cgroup. The writer should match all of the
+ following conditions.
+
+ - It must have write access to the "cgroup.threads" file.
+
+ - The cgroup that the thread is currently in must be in the
+ same resource domain as the destination cgroup.
+
+ - It must have write access to the "cgroup.procs" file of the
+ common ancestor of the source and destination cgroups.
+
+ When delegating a sub-hierarchy, write access to this file
+ should be granted along with the containing directory.
+
cgroup.controllers
A read-only space separated values file which exists on all
cgroups.
@@ -701,6 +854,38 @@ All cgroup core files are prefixed with "cgroup."
1 if the cgroup or its descendants contains any live
processes; otherwise, 0.
+ cgroup.max.descendants
+ A read-write single value files. The default is "max".
+
+ Maximum allowed number of descent cgroups.
+ If the actual number of descendants is equal or larger,
+ an attempt to create a new cgroup in the hierarchy will fail.
+
+ cgroup.max.depth
+ A read-write single value files. The default is "max".
+
+ Maximum allowed descent depth below the current cgroup.
+ If the actual descent depth is equal or larger,
+ an attempt to create a new child cgroup will fail.
+
+ cgroup.stat
+ A read-only flat-keyed file with the following entries:
+
+ nr_descendants
+ Total number of visible descendant cgroups.
+
+ nr_dying_descendants
+ Total number of dying descendant cgroups. A cgroup becomes
+ dying after being deleted by a user. The cgroup will remain
+ in dying state for some time undefined time (which can depend
+ on system load) before being completely destroyed.
+
+ A process can't enter a dying cgroup under any circumstances,
+ a dying cgroup can't revive.
+
+ A dying cgroup can consume system resources not exceeding
+ limits, which were active at the moment of cgroup deletion.
+
Controllers
===========
diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h
index 09f4c7df1478..ade4a78a54c2 100644
--- a/include/linux/cgroup-defs.h
+++ b/include/linux/cgroup-defs.h
@@ -74,6 +74,11 @@ enum {
* aren't writeable from inside the namespace.
*/
CGRP_ROOT_NS_DELEGATE = (1 << 3),
+
+ /*
+ * Enable cpuset controller in v1 cgroup to use v2 behavior.
+ */
+ CGRP_ROOT_CPUSET_V2_MODE = (1 << 4),
};
/* cftype->flags */
@@ -172,6 +177,14 @@ struct css_set {
/* reference count */
refcount_t refcount;
+ /*
+ * For a domain cgroup, the following points to self. If threaded,
+ * to the matching cset of the nearest domain ancestor. The
+ * dom_cset provides access to the domain cgroup and its csses to
+ * which domain level resource consumptions should be charged.
+ */
+ struct css_set *dom_cset;
+
/* the default cgroup associated with this css_set */
struct cgroup *dfl_cgrp;
@@ -200,6 +213,10 @@ struct css_set {
*/
struct list_head e_cset_node[CGROUP_SUBSYS_COUNT];
+ /* all threaded csets whose ->dom_cset points to this cset */
+ struct list_head threaded_csets;
+ struct list_head threaded_csets_node;
+
/*
* List running through all cgroup groups in the same hash
* slot. Protected by css_set_lock
@@ -261,13 +278,35 @@ struct cgroup {
*/
int level;
+ /* Maximum allowed descent tree depth */
+ int max_depth;
+
+ /*
+ * Keep track of total numbers of visible and dying descent cgroups.
+ * Dying cgroups are cgroups which were deleted by a user,
+ * but are still existing because someone else is holding a reference.
+ * max_descendants is a maximum allowed number of descent cgroups.
+ */
+ int nr_descendants;
+ int nr_dying_descendants;
+ int max_descendants;
+
/*
* Each non-empty css_set associated with this cgroup contributes
- * one to populated_cnt. All children with non-zero popuplated_cnt
- * of their own contribute one. The count is zero iff there's no
- * task in this cgroup or its subtree.
+ * one to nr_populated_csets. The counter is zero iff this cgroup
+ * doesn't have any tasks.
+ *
+ * All children which have non-zero nr_populated_csets and/or
+ * nr_populated_children of their own contribute one to either
+ * nr_populated_domain_children or nr_populated_threaded_children
+ * depending on their type. Each counter is zero iff all cgroups
+ * of the type in the subtree proper don't have any tasks.
*/
- int populated_cnt;
+ int nr_populated_csets;
+ int nr_populated_domain_children;
+ int nr_populated_threaded_children;
+
+ int nr_threaded_children; /* # of live threaded child cgroups */
struct kernfs_node *kn; /* cgroup kernfs entry */
struct cgroup_file procs_file; /* handle for "cgroup.procs" */
@@ -306,6 +345,15 @@ struct cgroup {
struct list_head e_csets[CGROUP_SUBSYS_COUNT];
/*
+ * If !threaded, self. If threaded, it points to the nearest
+ * domain ancestor. Inside a threaded subtree, cgroups are exempt
+ * from process granularity and no-internal-task constraint.
+ * Domain level resource consumptions which aren't tied to a
+ * specific task are charged to the dom_cgrp.
+ */
+ struct cgroup *dom_cgrp;
+
+ /*
* list of pidlists, up to two for each namespace (one for procs, one
* for tasks); created on demand.
*/
@@ -492,6 +540,18 @@ struct cgroup_subsys {
bool implicit_on_dfl:1;
/*
+ * If %true, the controller, supports threaded mode on the default
+ * hierarchy. In a threaded subtree, both process granularity and
+ * no-internal-process constraint are ignored and a threaded
+ * controllers should be able to handle that.
+ *
+ * Note that as an implicit controller is automatically enabled on
+ * all cgroups on the default hierarchy, it should also be
+ * threaded. implicit && !threaded is not supported.
+ */
+ bool threaded:1;
+
+ /*
* If %false, this subsystem is properly hierarchical -
* configuration, resource accounting and restriction on a parent
* cgroup cover those of its children. If %true, hierarchy support
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 710a005c6b7a..085056e562b1 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -36,18 +36,28 @@
#define CGROUP_WEIGHT_DFL 100
#define CGROUP_WEIGHT_MAX 10000
+/* walk only threadgroup leaders */
+#define CSS_TASK_ITER_PROCS (1U << 0)
+/* walk all threaded css_sets in the domain */
+#define CSS_TASK_ITER_THREADED (1U << 1)
+
/* a css_task_iter should be treated as an opaque object */
struct css_task_iter {
struct cgroup_subsys *ss;
+ unsigned int flags;
struct list_head *cset_pos;
struct list_head *cset_head;
+ struct list_head *tcset_pos;
+ struct list_head *tcset_head;
+
struct list_head *task_pos;
struct list_head *tasks_head;
struct list_head *mg_tasks_head;
struct css_set *cur_cset;
+ struct css_set *cur_dcset;
struct task_struct *cur_task;
struct list_head iters_node; /* css_set->task_iters */
};
@@ -129,7 +139,7 @@ struct task_struct *cgroup_taskset_first(struct cgroup_taskset *tset,
struct task_struct *cgroup_taskset_next(struct cgroup_taskset *tset,
struct cgroup_subsys_state **dst_cssp);
-void css_task_iter_start(struct cgroup_subsys_state *css,
+void css_task_iter_start(struct cgroup_subsys_state *css, unsigned int flags,
struct css_task_iter *it);
struct task_struct *css_task_iter_next(struct css_task_iter *it);
void css_task_iter_end(struct css_task_iter *it);
@@ -388,6 +398,16 @@ static inline void css_put_many(struct cgroup_subsys_state *css, unsigned int n)
percpu_ref_put_many(&css->refcnt, n);
}
+static inline void cgroup_get(struct cgroup *cgrp)
+{
+ css_get(&cgrp->self);
+}
+
+static inline bool cgroup_tryget(struct cgroup *cgrp)
+{
+ return css_tryget(&cgrp->self);
+}
+
static inline void cgroup_put(struct cgroup *cgrp)
{
css_put(&cgrp->self);
@@ -500,6 +520,20 @@ static inline struct cgroup *task_cgroup(struct task_struct *task,
return task_css(task, subsys_id)->cgroup;
}
+static inline struct cgroup *task_dfl_cgroup(struct task_struct *task)
+{
+ return task_css_set(task)->dfl_cgrp;
+}
+
+static inline struct cgroup *cgroup_parent(struct cgroup *cgrp)
+{
+ struct cgroup_subsys_state *parent_css = cgrp->self.parent;
+
+ if (parent_css)
+ return container_of(parent_css, struct cgroup, self);
+ return NULL;
+}
+
/**
* cgroup_is_descendant - test ancestry
* @cgrp: the cgroup to be tested
@@ -537,7 +571,8 @@ static inline bool task_under_cgroup_hierarchy(struct task_struct *task,
/* no synchronization, the result can only be used as a hint */
static inline bool cgroup_is_populated(struct cgroup *cgrp)
{
- return cgrp->populated_cnt;
+ return cgrp->nr_populated_csets + cgrp->nr_populated_domain_children +
+ cgrp->nr_populated_threaded_children;
}
/* returns ino associated with a cgroup */
diff --git a/kernel/cgroup/cgroup-internal.h b/kernel/cgroup/cgroup-internal.h
index 8b4c3c2f2509..5151ff256c29 100644
--- a/kernel/cgroup/cgroup-internal.h
+++ b/kernel/cgroup/cgroup-internal.h
@@ -156,6 +156,8 @@ static inline void get_css_set(struct css_set *cset)
bool cgroup_ssid_enabled(int ssid);
bool cgroup_on_dfl(const struct cgroup *cgrp);
+bool cgroup_is_thread_root(struct cgroup *cgrp);
+bool cgroup_is_threaded(struct cgroup *cgrp);
struct cgroup_root *cgroup_root_from_kf(struct kernfs_root *kf_root);
struct cgroup *task_cgroup_from_root(struct task_struct *task,
@@ -173,7 +175,7 @@ struct dentry *cgroup_do_mount(struct file_system_type *fs_type, int flags,
struct cgroup_root *root, unsigned long magic,
struct cgroup_namespace *ns);
-bool cgroup_may_migrate_to(struct cgroup *dst_cgrp);
+int cgroup_migrate_vet_dst(struct cgroup *dst_cgrp);
void cgroup_migrate_finish(struct cgroup_mgctx *mgctx);
void cgroup_migrate_add_src(struct css_set *src_cset, struct cgroup *dst_cgrp,
struct cgroup_mgctx *mgctx);
@@ -183,10 +185,10 @@ int cgroup_migrate(struct task_struct *leader, bool threadgroup,
int cgroup_attach_task(struct cgroup *dst_cgrp, struct task_struct *leader,
bool threadgroup);
-ssize_t __cgroup_procs_write(struct kernfs_open_file *of, char *buf,
- size_t nbytes, loff_t off, bool threadgroup);
-ssize_t cgroup_procs_write(struct kernfs_open_file *of, char *buf, size_t nbytes,
- loff_t off);
+struct task_struct *cgroup_procs_write_start(char *buf, bool threadgroup)
+ __acquires(&cgroup_threadgroup_rwsem);
+void cgroup_procs_write_finish(struct task_struct *task)
+ __releases(&cgroup_threadgroup_rwsem);
void cgroup_lock_and_drain_offline(struct cgroup *cgrp);
diff --git a/kernel/cgroup/cgroup-v1.c b/kernel/cgroup/cgroup-v1.c
index 7bf4b1533f34..024085daab1a 100644
--- a/kernel/cgroup/cgroup-v1.c
+++ b/kernel/cgroup/cgroup-v1.c
@@ -99,8 +99,9 @@ int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from)
if (cgroup_on_dfl(to))
return -EINVAL;
- if (!cgroup_may_migrate_to(to))
- return -EBUSY;
+ ret = cgroup_migrate_vet_dst(to);
+ if (ret)
+ return ret;
mutex_lock(&cgroup_mutex);
@@ -121,7 +122,7 @@ int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from)
* ->can_attach() fails.
*/
do {
- css_task_iter_start(&from->self, &it);
+ css_task_iter_start(&from->self, 0, &it);
task = css_task_iter_next(&it);
if (task)
get_task_struct(task);
@@ -373,7 +374,7 @@ static int pidlist_array_load(struct cgroup *cgrp, enum cgroup_filetype type,
if (!array)
return -ENOMEM;
/* now, populate the array */
- css_task_iter_start(&cgrp->self, &it);
+ css_task_iter_start(&cgrp->self, 0, &it);
while ((tsk = css_task_iter_next(&it))) {
if (unlikely(n == length))
break;
@@ -510,10 +511,58 @@ static int cgroup_pidlist_show(struct seq_file *s, void *v)
return 0;
}
-static ssize_t cgroup_tasks_write(struct kernfs_open_file *of,
- char *buf, size_t nbytes, loff_t off)
+static ssize_t __cgroup1_procs_write(struct kernfs_open_file *of,
+ char *buf, size_t nbytes, loff_t off,
+ bool threadgroup)
{
- return __cgroup_procs_write(of, buf, nbytes, off, false);
+ struct cgroup *cgrp;
+ struct task_struct *task;
+ const struct cred *cred, *tcred;
+ ssize_t ret;
+
+ cgrp = cgroup_kn_lock_live(of->kn, false);
+ if (!cgrp)
+ return -ENODEV;
+
+ task = cgroup_procs_write_start(buf, threadgroup);
+ ret = PTR_ERR_OR_ZERO(task);
+ if (ret)
+ goto out_unlock;
+
+ /*
+ * Even if we're attaching all tasks in the thread group, we only
+ * need to check permissions on one of them.
+ */
+ cred = current_cred();
+ tcred = get_task_cred(task);
+ if (!uid_eq(cred->euid, GLOBAL_ROOT_UID) &&
+ !uid_eq(cred->euid, tcred->uid) &&
+ !uid_eq(cred->euid, tcred->suid))
+ ret = -EACCES;
+ put_cred(tcred);
+ if (ret)
+ goto out_finish;
+
+ ret = cgroup_attach_task(cgrp, task, threadgroup);
+
+out_finish:
+ cgroup_procs_write_finish(task);
+out_unlock:
+ cgroup_kn_unlock(of->kn);
+
+ return ret ?: nbytes;
+}
+
+static ssize_t cgroup1_procs_write(struct kernfs_open_file *of,
+ char *buf, size_t nbytes, loff_t off)
+{
+ return __cgroup1_procs_write(of, buf, nbytes, off, true);
+}
+
+static ssize_t cgroup1_tasks_write(struct kernfs_open_file *of,
+ char *buf, size_t nbytes, loff_t off)
+{
+ return __cgroup1_procs_write(of, buf, nbytes, off, false);
}
static ssize_t cgroup_release_agent_write(struct kernfs_open_file *of,
@@ -592,7 +641,7 @@ struct cftype cgroup1_base_files[] = {
.seq_stop = cgroup_pidlist_stop,
.seq_show = cgroup_pidlist_show,
.private = CGROUP_FILE_PROCS,
- .write = cgroup_procs_write,
+ .write = cgroup1_procs_write,
},
{
.name = "cgroup.clone_children",
@@ -611,7 +660,7 @@ struct cftype cgroup1_base_files[] = {
.seq_stop = cgroup_pidlist_stop,
.seq_show = cgroup_pidlist_show,
.private = CGROUP_FILE_TASKS,
- .write = cgroup_tasks_write,
+ .write = cgroup1_tasks_write,
},
{
.name = "notify_on_release",
@@ -701,7 +750,7 @@ int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry)
}
rcu_read_unlock();
- css_task_iter_start(&cgrp->self, &it);
+ css_task_iter_start(&cgrp->self, 0, &it);
while ((tsk = css_task_iter_next(&it))) {
switch (tsk->state) {
case TASK_RUNNING:
@@ -846,6 +895,8 @@ static int cgroup1_show_options(struct seq_file *seq, struct kernfs_root *kf_roo
seq_puts(seq, ",noprefix");
if (root->flags & CGRP_ROOT_XATTR)
seq_puts(seq, ",xattr");
+ if (root->flags & CGRP_ROOT_CPUSET_V2_MODE)
+ seq_puts(seq, ",cpuset_v2_mode");
spin_lock(&release_agent_path_lock);
if (strlen(root->release_agent_path))
@@ -900,6 +951,10 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
opts->cpuset_clone_children = true;
continue;
}
+ if (!strcmp(token, "cpuset_v2_mode")) {
+ opts->flags |= CGRP_ROOT_CPUSET_V2_MODE;
+ continue;
+ }
if (!strcmp(token, "xattr")) {
opts->flags |= CGRP_ROOT_XATTR;
continue;
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index f64fc967a9ef..4f2196a00953 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -162,6 +162,9 @@ static u16 cgrp_dfl_inhibit_ss_mask;
/* some controllers are implicitly enabled on the default hierarchy */
static u16 cgrp_dfl_implicit_ss_mask;
+/* some controllers can be threaded on the default hierarchy */
+static u16 cgrp_dfl_threaded_ss_mask;
+
/* The list of hierarchy roots */
LIST_HEAD(cgroup_roots);
static int cgroup_root_count;
@@ -316,13 +319,87 @@ static void cgroup_idr_remove(struct idr *idr, int id)
spin_unlock_bh(&cgroup_idr_lock);
}
-static struct cgroup *cgroup_parent(struct cgroup *cgrp)
+static bool cgroup_has_tasks(struct cgroup *cgrp)
{
- struct cgroup_subsys_state *parent_css = cgrp->self.parent;
+ return cgrp->nr_populated_csets;
+}
- if (parent_css)
- return container_of(parent_css, struct cgroup, self);
- return NULL;
+bool cgroup_is_threaded(struct cgroup *cgrp)
+{
+ return cgrp->dom_cgrp != cgrp;
+}
+
+/* can @cgrp host both domain and threaded children? */
+static bool cgroup_is_mixable(struct cgroup *cgrp)
+{
+ /*
+ * Root isn't under domain level resource control exempting it from
+ * the no-internal-process constraint, so it can serve as a thread
+ * root and a parent of resource domains at the same time.
+ */
+ return !cgroup_parent(cgrp);
+}
+
+/* can @cgrp become a thread root? should always be true for a thread root */
+static bool cgroup_can_be_thread_root(struct cgroup *cgrp)
+{
+ /* mixables don't care */
+ if (cgroup_is_mixable(cgrp))
+ return true;
+
+ /* domain roots can't be nested under threaded */
+ if (cgroup_is_threaded(cgrp))
+ return false;
+
+ /* can only have either domain or threaded children */
+ if (cgrp->nr_populated_domain_children)
+ return false;
+
+ /* and no domain controllers can be enabled */
+ if (cgrp->subtree_control & ~cgrp_dfl_threaded_ss_mask)
+ return false;
+
+ return true;
+}
+
+/* is @cgrp root of a threaded subtree? */
+bool cgroup_is_thread_root(struct cgroup *cgrp)
+{
+ /* thread root should be a domain */
+ if (cgroup_is_threaded(cgrp))
+ return false;
+
+ /* a domain w/ threaded children is a thread root */
+ if (cgrp->nr_threaded_children)
+ return true;
+
+ /*
+ * A domain which has tasks and explicit threaded controllers
+ * enabled is a thread root.
+ */
+ if (cgroup_has_tasks(cgrp) &&
+ (cgrp->subtree_control & cgrp_dfl_threaded_ss_mask))
+ return true;
+
+ return false;
+}
+
+/* a domain which isn't connected to the root w/o brekage can't be used */
+static bool cgroup_is_valid_domain(struct cgroup *cgrp)
+{
+ /* the cgroup itself can be a thread root */
+ if (cgroup_is_threaded(cgrp))
+ return false;
+
+ /* but the ancestors can't be unless mixable */
+ while ((cgrp = cgroup_parent(cgrp))) {
+ if (!cgroup_is_mixable(cgrp) && cgroup_is_thread_root(cgrp))
+ return false;
+ if (cgroup_is_threaded(cgrp))
+ return false;
+ }
+
+ return true;
}
/* subsystems visibly enabled on a cgroup */
@@ -331,8 +408,14 @@ 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 (parent) {
+ u16 ss_mask = parent->subtree_control;
+
+ /* threaded cgroups can only have threaded controllers */
+ if (cgroup_is_threaded(cgrp))
+ ss_mask &= cgrp_dfl_threaded_ss_mask;
+ return ss_mask;
+ }
if (cgroup_on_dfl(cgrp))
root_ss_mask &= ~(cgrp_dfl_inhibit_ss_mask |
@@ -345,8 +428,14 @@ static u16 cgroup_ss_mask(struct cgroup *cgrp)
{
struct cgroup *parent = cgroup_parent(cgrp);
- if (parent)
- return parent->subtree_ss_mask;
+ if (parent) {
+ u16 ss_mask = parent->subtree_ss_mask;
+
+ /* threaded cgroups can only have threaded controllers */
+ if (cgroup_is_threaded(cgrp))
+ ss_mask &= cgrp_dfl_threaded_ss_mask;
+ return ss_mask;
+ }
return cgrp->root->subsys_mask;
}
@@ -436,22 +525,12 @@ out_unlock:
return css;
}
-static void __maybe_unused cgroup_get(struct cgroup *cgrp)
-{
- css_get(&cgrp->self);
-}
-
static void cgroup_get_live(struct cgroup *cgrp)
{
WARN_ON_ONCE(cgroup_is_dead(cgrp));
css_get(&cgrp->self);
}
-static bool cgroup_tryget(struct cgroup *cgrp)
-{
- return css_tryget(&cgrp->self);
-}
-
struct cgroup_subsys_state *of_css(struct kernfs_open_file *of)
{
struct cgroup *cgrp = of->kn->parent->priv;
@@ -560,9 +639,11 @@ EXPORT_SYMBOL_GPL(of_css);
*/
struct css_set init_css_set = {
.refcount = REFCOUNT_INIT(1),
+ .dom_cset = &init_css_set,
.tasks = LIST_HEAD_INIT(init_css_set.tasks),
.mg_tasks = LIST_HEAD_INIT(init_css_set.mg_tasks),
.task_iters = LIST_HEAD_INIT(init_css_set.task_iters),
+ .threaded_csets = LIST_HEAD_INIT(init_css_set.threaded_csets),
.cgrp_links = LIST_HEAD_INIT(init_css_set.cgrp_links),
.mg_preload_node = LIST_HEAD_INIT(init_css_set.mg_preload_node),
.mg_node = LIST_HEAD_INIT(init_css_set.mg_node),
@@ -570,6 +651,11 @@ struct css_set init_css_set = {
static int css_set_count = 1; /* 1 for init_css_set */
+static bool css_set_threaded(struct css_set *cset)
+{
+ return cset->dom_cset != cset;
+}
+
/**
* css_set_populated - does a css_set contain any tasks?
* @cset: target css_set
@@ -587,39 +673,48 @@ static bool css_set_populated(struct css_set *cset)
}
/**
- * cgroup_update_populated - updated populated count of a cgroup
+ * cgroup_update_populated - update the populated count of a cgroup
* @cgrp: the target cgroup
* @populated: inc or dec populated count
*
* One of the css_sets associated with @cgrp is either getting its first
- * task or losing the last. Update @cgrp->populated_cnt accordingly. The
- * count is propagated towards root so that a given cgroup's populated_cnt
- * is zero iff the cgroup and all its descendants don't contain any tasks.
+ * task or losing the last. Update @cgrp->nr_populated_* accordingly. The
+ * count is propagated towards root so that a given cgroup's
+ * nr_populated_children is zero iff none of its descendants contain any
+ * tasks.
*
- * @cgrp's interface file "cgroup.populated" is zero if
- * @cgrp->populated_cnt is zero and 1 otherwise. When @cgrp->populated_cnt
- * changes from or to zero, userland is notified that the content of the
- * interface file has changed. This can be used to detect when @cgrp and
- * its descendants become populated or empty.
+ * @cgrp's interface file "cgroup.populated" is zero if both
+ * @cgrp->nr_populated_csets and @cgrp->nr_populated_children are zero and
+ * 1 otherwise. When the sum changes from or to zero, userland is notified
+ * that the content of the interface file has changed. This can be used to
+ * detect when @cgrp and its descendants become populated or empty.
*/
static void cgroup_update_populated(struct cgroup *cgrp, bool populated)
{
+ struct cgroup *child = NULL;
+ int adj = populated ? 1 : -1;
+
lockdep_assert_held(&css_set_lock);
do {
- bool trigger;
+ bool was_populated = cgroup_is_populated(cgrp);
- if (populated)
- trigger = !cgrp->populated_cnt++;
- else
- trigger = !--cgrp->populated_cnt;
+ if (!child) {
+ cgrp->nr_populated_csets += adj;
+ } else {
+ if (cgroup_is_threaded(child))
+ cgrp->nr_populated_threaded_children += adj;
+ else
+ cgrp->nr_populated_domain_children += adj;
+ }
- if (!trigger)
+ if (was_populated == cgroup_is_populated(cgrp))
break;
cgroup1_check_for_release(cgrp);
cgroup_file_notify(&cgrp->events_file);
+ child = cgrp;
cgrp = cgroup_parent(cgrp);
} while (cgrp);
}
@@ -630,7 +725,7 @@ static void cgroup_update_populated(struct cgroup *cgrp, bool populated)
* @populated: whether @cset is populated or depopulated
*
* @cset is either getting the first task or losing the last. Update the
- * ->populated_cnt of all associated cgroups accordingly.
+ * populated counters of all associated cgroups accordingly.
*/
static void css_set_update_populated(struct css_set *cset, bool populated)
{
@@ -653,7 +748,7 @@ static void css_set_update_populated(struct css_set *cset, bool populated)
* css_set, @from_cset can be NULL. If @task is being disassociated
* instead of moved, @to_cset can be NULL.
*
- * This function automatically handles populated_cnt updates and
+ * This function automatically handles populated counter updates and
* css_task_iter adjustments but the caller is responsible for managing
* @from_cset and @to_cset's reference counts.
*/
@@ -737,6 +832,8 @@ void put_css_set_locked(struct css_set *cset)
if (!refcount_dec_and_test(&cset->refcount))
return;
+ WARN_ON_ONCE(!list_empty(&cset->threaded_csets));
+
/* This css_set is dead. unlink it and release cgroup and css refs */
for_each_subsys(ss, ssid) {
list_del(&cset->e_cset_node[ssid]);
@@ -753,6 +850,11 @@ void put_css_set_locked(struct css_set *cset)
kfree(link);
}
+ if (css_set_threaded(cset)) {
+ list_del(&cset->threaded_csets_node);
+ put_css_set_locked(cset->dom_cset);
+ }
+
kfree_rcu(cset, rcu_head);
}
@@ -771,6 +873,7 @@ static bool compare_css_sets(struct css_set *cset,
struct cgroup *new_cgrp,
struct cgroup_subsys_state *template[])
{
+ struct cgroup *new_dfl_cgrp;
struct list_head *l1, *l2;
/*
@@ -781,6 +884,16 @@ static bool compare_css_sets(struct css_set *cset,
if (memcmp(template, cset->subsys, sizeof(cset->subsys)))
return false;
+
+ /* @cset's domain should match the default cgroup's */
+ if (cgroup_on_dfl(new_cgrp))
+ new_dfl_cgrp = new_cgrp;
+ else
+ new_dfl_cgrp = old_cset->dfl_cgrp;
+
+ if (new_dfl_cgrp->dom_cgrp != cset->dom_cset->dfl_cgrp)
+ return false;
+
/*
* Compare cgroup pointers in order to distinguish between
* different cgroups in hierarchies. As different cgroups may
@@ -988,9 +1101,11 @@ static struct css_set *find_css_set(struct css_set *old_cset,
}
refcount_set(&cset->refcount, 1);
+ cset->dom_cset = cset;
INIT_LIST_HEAD(&cset->tasks);
INIT_LIST_HEAD(&cset->mg_tasks);
INIT_LIST_HEAD(&cset->task_iters);
+ INIT_LIST_HEAD(&cset->threaded_csets);
INIT_HLIST_NODE(&cset->hlist);
INIT_LIST_HEAD(&cset->cgrp_links);
INIT_LIST_HEAD(&cset->mg_preload_node);
@@ -1028,6 +1143,28 @@ static struct css_set *find_css_set(struct css_set *old_cset,
spin_unlock_irq(&css_set_lock);
+ /*
+ * If @cset should be threaded, look up the matching dom_cset and
+ * link them up. We first fully initialize @cset then look for the
+ * dom_cset. It's simpler this way and safe as @cset is guaranteed
+ * to stay empty until we return.
+ */
+ if (cgroup_is_threaded(cset->dfl_cgrp)) {
+ struct css_set *dcset;
+
+ dcset = find_css_set(cset, cset->dfl_cgrp->dom_cgrp);
+ if (!dcset) {
+ put_css_set(cset);
+ return NULL;
+ }
+
+ spin_lock_irq(&css_set_lock);
+ cset->dom_cset = dcset;
+ list_add_tail(&cset->threaded_csets_node,
+ &dcset->threaded_csets);
+ spin_unlock_irq(&css_set_lock);
+ }
+
return cset;
}
@@ -1155,6 +1292,8 @@ static struct cgroup *cset_cgroup_from_root(struct css_set *cset,
if (cset == &init_css_set) {
res = &root->cgrp;
+ } else if (root == &cgrp_dfl_root) {
+ res = cset->dfl_cgrp;
} else {
struct cgrp_cset_link *link;
@@ -1670,6 +1809,9 @@ static void init_cgroup_housekeeping(struct cgroup *cgrp)
mutex_init(&cgrp->pidlist_mutex);
cgrp->self.cgroup = cgrp;
cgrp->self.flags |= CSS_ONLINE;
+ cgrp->dom_cgrp = cgrp;
+ cgrp->max_descendants = INT_MAX;
+ cgrp->max_depth = INT_MAX;
for_each_subsys(ss, ssid)
INIT_LIST_HEAD(&cgrp->e_csets[ssid]);
@@ -2172,17 +2314,40 @@ out_release_tset:
}
/**
- * cgroup_may_migrate_to - verify whether a cgroup can be migration destination
+ * cgroup_migrate_vet_dst - 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.
+ * On the default hierarchy, except for the mixable, (possible) thread root
+ * and threaded cgroups, subtree_control must be zero for migration
+ * destination cgroups with tasks so that child cgroups don't compete
+ * against tasks.
*/
-bool cgroup_may_migrate_to(struct cgroup *dst_cgrp)
+int cgroup_migrate_vet_dst(struct cgroup *dst_cgrp)
{
- return !cgroup_on_dfl(dst_cgrp) || !cgroup_parent(dst_cgrp) ||
- !dst_cgrp->subtree_control;
+ /* v1 doesn't have any restriction */
+ if (!cgroup_on_dfl(dst_cgrp))
+ return 0;
+
+ /* verify @dst_cgrp can host resources */
+ if (!cgroup_is_valid_domain(dst_cgrp->dom_cgrp))
+ return -EOPNOTSUPP;
+
+ /* mixables don't care */
+ if (cgroup_is_mixable(dst_cgrp))
+ return 0;
+
+ /*
+ * If @dst_cgrp is already or can become a thread root or is
+ * threaded, it doesn't matter.
+ */
+ if (cgroup_can_be_thread_root(dst_cgrp) || cgroup_is_threaded(dst_cgrp))
+ return 0;
+
+ /* apply no-internal-process constraint */
+ if (dst_cgrp->subtree_control)
+ return -EBUSY;
+
+ return 0;
}
/**
@@ -2387,8 +2552,9 @@ int cgroup_attach_task(struct cgroup *dst_cgrp, struct task_struct *leader,
struct task_struct *task;
int ret;
- if (!cgroup_may_migrate_to(dst_cgrp))
- return -EBUSY;
+ ret = cgroup_migrate_vet_dst(dst_cgrp);
+ if (ret)
+ return ret;
/* look up all src csets */
spin_lock_irq(&css_set_lock);
@@ -2415,96 +2581,23 @@ int cgroup_attach_task(struct cgroup *dst_cgrp, struct task_struct *leader,
return ret;
}
-static int cgroup_procs_write_permission(struct task_struct *task,
- struct cgroup *dst_cgrp,
- struct kernfs_open_file *of)
-{
- struct super_block *sb = of->file->f_path.dentry->d_sb;
- struct cgroup_namespace *ns = current->nsproxy->cgroup_ns;
- struct cgroup *root_cgrp = ns->root_cset->dfl_cgrp;
- struct cgroup *src_cgrp, *com_cgrp;
- struct inode *inode;
- int ret;
-
- if (!cgroup_on_dfl(dst_cgrp)) {
- const struct cred *cred = current_cred();
- const struct cred *tcred = get_task_cred(task);
-
- /*
- * even if we're attaching all tasks in the thread group,
- * we only need to check permissions on one of them.
- */
- if (uid_eq(cred->euid, GLOBAL_ROOT_UID) ||
- uid_eq(cred->euid, tcred->uid) ||
- uid_eq(cred->euid, tcred->suid))
- ret = 0;
- else
- ret = -EACCES;
-
- put_cred(tcred);
- return ret;
- }
-
- /* find the source cgroup */
- spin_lock_irq(&css_set_lock);
- src_cgrp = task_cgroup_from_root(task, &cgrp_dfl_root);
- spin_unlock_irq(&css_set_lock);
-
- /* and the common ancestor */
- com_cgrp = src_cgrp;
- while (!cgroup_is_descendant(dst_cgrp, com_cgrp))
- com_cgrp = cgroup_parent(com_cgrp);
-
- /* %current should be authorized to migrate to the common ancestor */
- inode = kernfs_get_inode(sb, com_cgrp->procs_file.kn);
- if (!inode)
- return -ENOMEM;
-
- ret = inode_permission(inode, MAY_WRITE);
- iput(inode);
- if (ret)
- return ret;
-
- /*
- * If namespaces are delegation boundaries, %current must be able
- * to see both source and destination cgroups from its namespace.
- */
- if ((cgrp_dfl_root.flags & CGRP_ROOT_NS_DELEGATE) &&
- (!cgroup_is_descendant(src_cgrp, root_cgrp) ||
- !cgroup_is_descendant(dst_cgrp, root_cgrp)))
- return -ENOENT;
-
- return 0;
-}
-
-/*
- * Find the task_struct of the task to attach by vpid and pass it along to the
- * function to attach either it or all tasks in its threadgroup. Will lock
- * cgroup_mutex and threadgroup.
- */
-ssize_t __cgroup_procs_write(struct kernfs_open_file *of, char *buf,
- size_t nbytes, loff_t off, bool threadgroup)
+struct task_struct *cgroup_procs_write_start(char *buf, bool threadgroup)
+ __acquires(&cgroup_threadgroup_rwsem)
{
struct task_struct *tsk;
- struct cgroup_subsys *ss;
- struct cgroup *cgrp;
pid_t pid;
- int ssid, ret;
if (kstrtoint(strstrip(buf), 0, &pid) || pid < 0)
- return -EINVAL;
-
- cgrp = cgroup_kn_lock_live(of->kn, false);
- if (!cgrp)
- return -ENODEV;
+ return ERR_PTR(-EINVAL);
percpu_down_write(&cgroup_threadgroup_rwsem);
+
rcu_read_lock();
if (pid) {
tsk = find_task_by_vpid(pid);
if (!tsk) {
- ret = -ESRCH;
- goto out_unlock_rcu;
+ tsk = ERR_PTR(-ESRCH);
+ goto out_unlock_threadgroup;
}
} else {
tsk = current;
@@ -2520,35 +2613,33 @@ ssize_t __cgroup_procs_write(struct kernfs_open_file *of, char *buf,
* cgroup with no rt_runtime allocated. Just say no.
*/
if (tsk->no_cgroup_migration || (tsk->flags & PF_NO_SETAFFINITY)) {
- ret = -EINVAL;
- goto out_unlock_rcu;
+ tsk = ERR_PTR(-EINVAL);
+ goto out_unlock_threadgroup;
}
get_task_struct(tsk);
+ goto out_unlock_rcu;
+
+out_unlock_threadgroup:
+ percpu_up_write(&cgroup_threadgroup_rwsem);
+out_unlock_rcu:
rcu_read_unlock();
+ return tsk;
+}
- ret = cgroup_procs_write_permission(tsk, cgrp, of);
- if (!ret)
- ret = cgroup_attach_task(cgrp, tsk, threadgroup);
+void cgroup_procs_write_finish(struct task_struct *task)
+ __releases(&cgroup_threadgroup_rwsem)
+{
+ struct cgroup_subsys *ss;
+ int ssid;
- put_task_struct(tsk);
- goto out_unlock_threadgroup;
+ /* release reference from cgroup_procs_write_start() */
+ put_task_struct(task);
-out_unlock_rcu:
- rcu_read_unlock();
-out_unlock_threadgroup:
percpu_up_write(&cgroup_threadgroup_rwsem);
for_each_subsys(ss, ssid)
if (ss->post_attach)
ss->post_attach();
- cgroup_kn_unlock(of->kn);
- return ret ?: nbytes;
-}
-
-ssize_t cgroup_procs_write(struct kernfs_open_file *of, char *buf, size_t nbytes,
- loff_t off)
-{
- return __cgroup_procs_write(of, buf, nbytes, off, true);
}
static void cgroup_print_ss_mask(struct seq_file *seq, u16 ss_mask)
@@ -2891,6 +2982,46 @@ static void cgroup_finalize_control(struct cgroup *cgrp, int ret)
cgroup_apply_control_disable(cgrp);
}
+static int cgroup_vet_subtree_control_enable(struct cgroup *cgrp, u16 enable)
+{
+ u16 domain_enable = enable & ~cgrp_dfl_threaded_ss_mask;
+
+ /* if nothing is getting enabled, nothing to worry about */
+ if (!enable)
+ return 0;
+
+ /* can @cgrp host any resources? */
+ if (!cgroup_is_valid_domain(cgrp->dom_cgrp))
+ return -EOPNOTSUPP;
+
+ /* mixables don't care */
+ if (cgroup_is_mixable(cgrp))
+ return 0;
+
+ if (domain_enable) {
+ /* can't enable domain controllers inside a thread subtree */
+ if (cgroup_is_thread_root(cgrp) || cgroup_is_threaded(cgrp))
+ return -EOPNOTSUPP;
+ } else {
+ /*
+ * Threaded controllers can handle internal competitions
+ * and are always allowed inside a (prospective) thread
+ * subtree.
+ */
+ if (cgroup_can_be_thread_root(cgrp) || cgroup_is_threaded(cgrp))
+ return 0;
+ }
+
+ /*
+ * Controllers can't be enabled for a cgroup with tasks to avoid
+ * child cgroups competing against tasks.
+ */
+ if (cgroup_has_tasks(cgrp))
+ return -EBUSY;
+
+ return 0;
+}
+
/* 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,
@@ -2966,33 +3097,9 @@ static ssize_t cgroup_subtree_control_write(struct kernfs_open_file *of,
goto out_unlock;
}
- /*
- * Except for the root, subtree_control must be zero for a cgroup
- * with tasks so that child cgroups don't compete against tasks.
- */
- if (enable && cgroup_parent(cgrp)) {
- struct cgrp_cset_link *link;
-
- /*
- * Because namespaces pin csets too, @cgrp->cset_links
- * might not be empty even when @cgrp is empty. Walk and
- * verify each cset.
- */
- spin_lock_irq(&css_set_lock);
-
- ret = 0;
- list_for_each_entry(link, &cgrp->cset_links, cset_link) {
- if (css_set_populated(link->cset)) {
- ret = -EBUSY;
- break;
- }
- }
-
- spin_unlock_irq(&css_set_lock);
-
- if (ret)
- goto out_unlock;
- }
+ ret = cgroup_vet_subtree_control_enable(cgrp, enable);
+ if (ret)
+ goto out_unlock;
/* save and update control masks and prepare csses */
cgroup_save_control(cgrp);
@@ -3011,6 +3118,172 @@ out_unlock:
return ret ?: nbytes;
}
+/**
+ * cgroup_enable_threaded - make @cgrp threaded
+ * @cgrp: the target cgroup
+ *
+ * Called when "threaded" is written to the cgroup.type interface file and
+ * tries to make @cgrp threaded and join the parent's resource domain.
+ * This function is never called on the root cgroup as cgroup.type doesn't
+ * exist on it.
+ */
+static int cgroup_enable_threaded(struct cgroup *cgrp)
+{
+ struct cgroup *parent = cgroup_parent(cgrp);
+ struct cgroup *dom_cgrp = parent->dom_cgrp;
+ int ret;
+
+ lockdep_assert_held(&cgroup_mutex);
+
+ /* noop if already threaded */
+ if (cgroup_is_threaded(cgrp))
+ return 0;
+
+ /* we're joining the parent's domain, ensure its validity */
+ if (!cgroup_is_valid_domain(dom_cgrp) ||
+ !cgroup_can_be_thread_root(dom_cgrp))
+ return -EOPNOTSUPP;
+
+ /*
+ * The following shouldn't cause actual migrations and should
+ * always succeed.
+ */
+ cgroup_save_control(cgrp);
+
+ cgrp->dom_cgrp = dom_cgrp;
+ ret = cgroup_apply_control(cgrp);
+ if (!ret)
+ parent->nr_threaded_children++;
+ else
+ cgrp->dom_cgrp = cgrp;
+
+ cgroup_finalize_control(cgrp, ret);
+ return ret;
+}
+
+static int cgroup_type_show(struct seq_file *seq, void *v)
+{
+ struct cgroup *cgrp = seq_css(seq)->cgroup;
+
+ if (cgroup_is_threaded(cgrp))
+ seq_puts(seq, "threaded\n");
+ else if (!cgroup_is_valid_domain(cgrp))
+ seq_puts(seq, "domain invalid\n");
+ else if (cgroup_is_thread_root(cgrp))
+ seq_puts(seq, "domain threaded\n");
+ else
+ seq_puts(seq, "domain\n");
+
+ return 0;
+}
+
+static ssize_t cgroup_type_write(struct kernfs_open_file *of, char *buf,
+ size_t nbytes, loff_t off)
+{
+ struct cgroup *cgrp;
+ int ret;
+
+ /* only switching to threaded mode is supported */
+ if (strcmp(strstrip(buf), "threaded"))
+ return -EINVAL;
+
+ cgrp = cgroup_kn_lock_live(of->kn, false);
+ if (!cgrp)
+ return -ENOENT;
+
+ /* threaded can only be enabled */
+ ret = cgroup_enable_threaded(cgrp);
+
+ cgroup_kn_unlock(of->kn);
+ return ret ?: nbytes;
+}
+
+static int cgroup_max_descendants_show(struct seq_file *seq, void *v)
+{
+ struct cgroup *cgrp = seq_css(seq)->cgroup;
+ int descendants = READ_ONCE(cgrp->max_descendants);
+
+ if (descendants == INT_MAX)
+ seq_puts(seq, "max\n");
+ else
+ seq_printf(seq, "%d\n", descendants);
+
+ return 0;
+}
+
+static ssize_t cgroup_max_descendants_write(struct kernfs_open_file *of,
+ char *buf, size_t nbytes, loff_t off)
+{
+ struct cgroup *cgrp;
+ int descendants;
+ ssize_t ret;
+
+ buf = strstrip(buf);
+ if (!strcmp(buf, "max")) {
+ descendants = INT_MAX;
+ } else {
+ ret = kstrtoint(buf, 0, &descendants);
+ if (ret)
+ return ret;
+ }
+
+ if (descendants < 0)
+ return -ERANGE;
+
+ cgrp = cgroup_kn_lock_live(of->kn, false);
+ if (!cgrp)
+ return -ENOENT;
+
+ cgrp->max_descendants = descendants;
+
+ cgroup_kn_unlock(of->kn);
+
+ return nbytes;
+}
+
+static int cgroup_max_depth_show(struct seq_file *seq, void *v)
+{
+ struct cgroup *cgrp = seq_css(seq)->cgroup;
+ int depth = READ_ONCE(cgrp->max_depth);
+
+ if (depth == INT_MAX)
+ seq_puts(seq, "max\n");
+ else
+ seq_printf(seq, "%d\n", depth);
+
+ return 0;
+}
+
+static ssize_t cgroup_max_depth_write(struct kernfs_open_file *of,
+ char *buf, size_t nbytes, loff_t off)
+{
+ struct cgroup *cgrp;
+ ssize_t ret;
+ int depth;
+
+ buf = strstrip(buf);
+ if (!strcmp(buf, "max")) {
+ depth = INT_MAX;
+ } else {
+ ret = kstrtoint(buf, 0, &depth);
+ if (ret)
+ return ret;
+ }
+
+ if (depth < 0)
+ return -ERANGE;
+
+ cgrp = cgroup_kn_lock_live(of->kn, false);
+ if (!cgrp)
+ return -ENOENT;
+
+ cgrp->max_depth = depth;
+
+ cgroup_kn_unlock(of->kn);
+
+ return nbytes;
+}
+
static int cgroup_events_show(struct seq_file *seq, void *v)
{
seq_printf(seq, "populated %d\n",
@@ -3018,6 +3291,18 @@ static int cgroup_events_show(struct seq_file *seq, void *v)
return 0;
}
+static int cgroup_stat_show(struct seq_file *seq, void *v)
+{
+ struct cgroup *cgroup = seq_css(seq)->cgroup;
+
+ seq_printf(seq, "nr_descendants %d\n",
+ cgroup->nr_descendants);
+ seq_printf(seq, "nr_dying_descendants %d\n",
+ cgroup->nr_dying_descendants);
+
+ return 0;
+}
+
static int cgroup_file_open(struct kernfs_open_file *of)
{
struct cftype *cft = of->kn->priv;
@@ -3234,7 +3519,6 @@ restart:
static int cgroup_apply_cftypes(struct cftype *cfts, bool is_add)
{
- LIST_HEAD(pending);
struct cgroup_subsys *ss = cfts[0].ss;
struct cgroup *root = &ss->root->cgrp;
struct cgroup_subsys_state *css;
@@ -3659,6 +3943,58 @@ bool css_has_online_children(struct cgroup_subsys_state *css)
return ret;
}
+static struct css_set *css_task_iter_next_css_set(struct css_task_iter *it)
+{
+ struct list_head *l;
+ struct cgrp_cset_link *link;
+ struct css_set *cset;
+
+ lockdep_assert_held(&css_set_lock);
+
+ /* find the next threaded cset */
+ if (it->tcset_pos) {
+ l = it->tcset_pos->next;
+
+ if (l != it->tcset_head) {
+ it->tcset_pos = l;
+ return container_of(l, struct css_set,
+ threaded_csets_node);
+ }
+
+ it->tcset_pos = NULL;
+ }
+
+ /* find the next cset */
+ l = it->cset_pos;
+ l = l->next;
+ if (l == it->cset_head) {
+ it->cset_pos = NULL;
+ return NULL;
+ }
+
+ if (it->ss) {
+ cset = container_of(l, struct css_set, e_cset_node[it->ss->id]);
+ } else {
+ link = list_entry(l, struct cgrp_cset_link, cset_link);
+ cset = link->cset;
+ }
+
+ it->cset_pos = l;
+
+ /* initialize threaded css_set walking */
+ if (it->flags & CSS_TASK_ITER_THREADED) {
+ if (it->cur_dcset)
+ put_css_set_locked(it->cur_dcset);
+ it->cur_dcset = cset;
+ get_css_set(cset);
+
+ it->tcset_head = &cset->threaded_csets;
+ it->tcset_pos = &cset->threaded_csets;
+ }
+
+ return cset;
+}
+
/**
* css_task_iter_advance_css_set - advance a task itererator to the next css_set
* @it: the iterator to advance
@@ -3667,32 +4003,19 @@ bool css_has_online_children(struct cgroup_subsys_state *css)
*/
static void css_task_iter_advance_css_set(struct css_task_iter *it)
{
- struct list_head *l = it->cset_pos;
- struct cgrp_cset_link *link;
struct css_set *cset;
lockdep_assert_held(&css_set_lock);
/* Advance to the next non-empty css_set */
do {
- l = l->next;
- if (l == it->cset_head) {
- it->cset_pos = NULL;
+ cset = css_task_iter_next_css_set(it);
+ if (!cset) {
it->task_pos = NULL;
return;
}
-
- if (it->ss) {
- cset = container_of(l, struct css_set,
- e_cset_node[it->ss->id]);
- } else {
- link = list_entry(l, struct cgrp_cset_link, cset_link);
- cset = link->cset;
- }
} while (!css_set_populated(cset));
- it->cset_pos = l;
-
if (!list_empty(&cset->tasks))
it->task_pos = cset->tasks.next;
else
@@ -3732,6 +4055,7 @@ static void css_task_iter_advance(struct css_task_iter *it)
lockdep_assert_held(&css_set_lock);
WARN_ON_ONCE(!l);
+repeat:
/*
* Advance iterator to find next entry. cset->tasks is consumed
* first and then ->mg_tasks. After ->mg_tasks, we move onto the
@@ -3746,11 +4070,18 @@ static void css_task_iter_advance(struct css_task_iter *it)
css_task_iter_advance_css_set(it);
else
it->task_pos = l;
+
+ /* if PROCS, skip over tasks which aren't group leaders */
+ if ((it->flags & CSS_TASK_ITER_PROCS) && it->task_pos &&
+ !thread_group_leader(list_entry(it->task_pos, struct task_struct,
+ cg_list)))
+ goto repeat;
}
/**
* css_task_iter_start - initiate task iteration
* @css: the css to walk tasks of
+ * @flags: CSS_TASK_ITER_* flags
* @it: the task iterator to use
*
* Initiate iteration through the tasks of @css. The caller can call
@@ -3758,7 +4089,7 @@ static void css_task_iter_advance(struct css_task_iter *it)
* returns NULL. On completion of iteration, css_task_iter_end() must be
* called.
*/
-void css_task_iter_start(struct cgroup_subsys_state *css,
+void css_task_iter_start(struct cgroup_subsys_state *css, unsigned int flags,
struct css_task_iter *it)
{
/* no one should try to iterate before mounting cgroups */
@@ -3769,6 +4100,7 @@ void css_task_iter_start(struct cgroup_subsys_state *css,
spin_lock_irq(&css_set_lock);
it->ss = css->ss;
+ it->flags = flags;
if (it->ss)
it->cset_pos = &css->cgroup->e_csets[css->ss->id];
@@ -3826,6 +4158,9 @@ void css_task_iter_end(struct css_task_iter *it)
spin_unlock_irq(&css_set_lock);
}
+ if (it->cur_dcset)
+ put_css_set(it->cur_dcset);
+
if (it->cur_task)
put_task_struct(it->cur_task);
}
@@ -3842,16 +4177,12 @@ static void *cgroup_procs_next(struct seq_file *s, void *v, loff_t *pos)
{
struct kernfs_open_file *of = s->private;
struct css_task_iter *it = of->priv;
- struct task_struct *task;
- do {
- task = css_task_iter_next(it);
- } while (task && !thread_group_leader(task));
-
- return task;
+ return css_task_iter_next(it);
}
-static void *cgroup_procs_start(struct seq_file *s, loff_t *pos)
+static void *__cgroup_procs_start(struct seq_file *s, loff_t *pos,
+ unsigned int iter_flags)
{
struct kernfs_open_file *of = s->private;
struct cgroup *cgrp = seq_css(s)->cgroup;
@@ -3869,24 +4200,169 @@ static void *cgroup_procs_start(struct seq_file *s, loff_t *pos)
if (!it)
return ERR_PTR(-ENOMEM);
of->priv = it;
- css_task_iter_start(&cgrp->self, it);
+ css_task_iter_start(&cgrp->self, iter_flags, it);
} else if (!(*pos)++) {
css_task_iter_end(it);
- css_task_iter_start(&cgrp->self, it);
+ css_task_iter_start(&cgrp->self, iter_flags, it);
}
return cgroup_procs_next(s, NULL, NULL);
}
+static void *cgroup_procs_start(struct seq_file *s, loff_t *pos)
+{
+ struct cgroup *cgrp = seq_css(s)->cgroup;
+
+ /*
+ * All processes of a threaded subtree belong to the domain cgroup
+ * of the subtree. Only threads can be distributed across the
+ * subtree. Reject reads on cgroup.procs in the subtree proper.
+ * They're always empty anyway.
+ */
+ if (cgroup_is_threaded(cgrp))
+ return ERR_PTR(-EOPNOTSUPP);
+
+ return __cgroup_procs_start(s, pos, CSS_TASK_ITER_PROCS |
+ CSS_TASK_ITER_THREADED);
+}
+
static int cgroup_procs_show(struct seq_file *s, void *v)
{
- seq_printf(s, "%d\n", task_tgid_vnr(v));
+ seq_printf(s, "%d\n", task_pid_vnr(v));
return 0;
}
+static int cgroup_procs_write_permission(struct cgroup *src_cgrp,
+ struct cgroup *dst_cgrp,
+ struct super_block *sb)
+{
+ struct cgroup_namespace *ns = current->nsproxy->cgroup_ns;
+ struct cgroup *com_cgrp = src_cgrp;
+ struct inode *inode;
+ int ret;
+
+ lockdep_assert_held(&cgroup_mutex);
+
+ /* find the common ancestor */
+ while (!cgroup_is_descendant(dst_cgrp, com_cgrp))
+ com_cgrp = cgroup_parent(com_cgrp);
+
+ /* %current should be authorized to migrate to the common ancestor */
+ inode = kernfs_get_inode(sb, com_cgrp->procs_file.kn);
+ if (!inode)
+ return -ENOMEM;
+
+ ret = inode_permission(inode, MAY_WRITE);
+ iput(inode);
+ if (ret)
+ return ret;
+
+ /*
+ * If namespaces are delegation boundaries, %current must be able
+ * to see both source and destination cgroups from its namespace.
+ */
+ if ((cgrp_dfl_root.flags & CGRP_ROOT_NS_DELEGATE) &&
+ (!cgroup_is_descendant(src_cgrp, ns->root_cset->dfl_cgrp) ||
+ !cgroup_is_descendant(dst_cgrp, ns->root_cset->dfl_cgrp)))
+ return -ENOENT;
+
+ return 0;
+}
+
+static ssize_t cgroup_procs_write(struct kernfs_open_file *of,
+ char *buf, size_t nbytes, loff_t off)
+{
+ struct cgroup *src_cgrp, *dst_cgrp;
+ struct task_struct *task;
+ ssize_t ret;
+
+ dst_cgrp = cgroup_kn_lock_live(of->kn, false);
+ if (!dst_cgrp)
+ return -ENODEV;
+
+ task = cgroup_procs_write_start(buf, true);
+ ret = PTR_ERR_OR_ZERO(task);
+ if (ret)
+ goto out_unlock;
+
+ /* find the source cgroup */
+ spin_lock_irq(&css_set_lock);
+ src_cgrp = task_cgroup_from_root(task, &cgrp_dfl_root);
+ spin_unlock_irq(&css_set_lock);
+
+ ret = cgroup_procs_write_permission(src_cgrp, dst_cgrp,
+ of->file->f_path.dentry->d_sb);
+ if (ret)
+ goto out_finish;
+
+ ret = cgroup_attach_task(dst_cgrp, task, true);
+
+out_finish:
+ cgroup_procs_write_finish(task);
+out_unlock:
+ cgroup_kn_unlock(of->kn);
+
+ return ret ?: nbytes;
+}
+
+static void *cgroup_threads_start(struct seq_file *s, loff_t *pos)
+{
+ return __cgroup_procs_start(s, pos, 0);
+}
+
+static ssize_t cgroup_threads_write(struct kernfs_open_file *of,
+ char *buf, size_t nbytes, loff_t off)
+{
+ struct cgroup *src_cgrp, *dst_cgrp;
+ struct task_struct *task;
+ ssize_t ret;
+
+ buf = strstrip(buf);
+
+ dst_cgrp = cgroup_kn_lock_live(of->kn, false);
+ if (!dst_cgrp)
+ return -ENODEV;
+
+ task = cgroup_procs_write_start(buf, false);
+ ret = PTR_ERR_OR_ZERO(task);
+ if (ret)
+ goto out_unlock;
+
+ /* find the source cgroup */
+ spin_lock_irq(&css_set_lock);
+ src_cgrp = task_cgroup_from_root(task, &cgrp_dfl_root);
+ spin_unlock_irq(&css_set_lock);
+
+ /* thread migrations follow the cgroup.procs delegation rule */
+ ret = cgroup_procs_write_permission(src_cgrp, dst_cgrp,
+ of->file->f_path.dentry->d_sb);
+ if (ret)
+ goto out_finish;
+
+ /* and must be contained in the same domain */
+ ret = -EOPNOTSUPP;
+ if (src_cgrp->dom_cgrp != dst_cgrp->dom_cgrp)
+ goto out_finish;
+
+ ret = cgroup_attach_task(dst_cgrp, task, false);
+
+out_finish:
+ cgroup_procs_write_finish(task);
+out_unlock:
+ cgroup_kn_unlock(of->kn);
+
+ return ret ?: nbytes;
+}
+
/* cgroup core interface files for the default hierarchy */
static struct cftype cgroup_base_files[] = {
{
+ .name = "cgroup.type",
+ .flags = CFTYPE_NOT_ON_ROOT,
+ .seq_show = cgroup_type_show,
+ .write = cgroup_type_write,
+ },
+ {
.name = "cgroup.procs",
.flags = CFTYPE_NS_DELEGATABLE,
.file_offset = offsetof(struct cgroup, procs_file),
@@ -3897,6 +4373,14 @@ static struct cftype cgroup_base_files[] = {
.write = cgroup_procs_write,
},
{
+ .name = "cgroup.threads",
+ .release = cgroup_procs_release,
+ .seq_start = cgroup_threads_start,
+ .seq_next = cgroup_procs_next,
+ .seq_show = cgroup_procs_show,
+ .write = cgroup_threads_write,
+ },
+ {
.name = "cgroup.controllers",
.seq_show = cgroup_controllers_show,
},
@@ -3912,6 +4396,20 @@ static struct cftype cgroup_base_files[] = {
.file_offset = offsetof(struct cgroup, events_file),
.seq_show = cgroup_events_show,
},
+ {
+ .name = "cgroup.max.descendants",
+ .seq_show = cgroup_max_descendants_show,
+ .write = cgroup_max_descendants_write,
+ },
+ {
+ .name = "cgroup.max.depth",
+ .seq_show = cgroup_max_depth_show,
+ .write = cgroup_max_depth_write,
+ },
+ {
+ .name = "cgroup.stat",
+ .seq_show = cgroup_stat_show,
+ },
{ } /* terminate */
};
@@ -4011,9 +4509,15 @@ static void css_release_work_fn(struct work_struct *work)
if (ss->css_released)
ss->css_released(css);
} else {
+ struct cgroup *tcgrp;
+
/* cgroup release path */
trace_cgroup_release(cgrp);
+ for (tcgrp = cgroup_parent(cgrp); tcgrp;
+ tcgrp = cgroup_parent(tcgrp))
+ tcgrp->nr_dying_descendants--;
+
cgroup_idr_remove(&cgrp->root->cgroup_idr, cgrp->id);
cgrp->id = -1;
@@ -4209,9 +4713,13 @@ static struct cgroup *cgroup_create(struct cgroup *parent)
cgrp->root = root;
cgrp->level = level;
- for (tcgrp = cgrp; tcgrp; tcgrp = cgroup_parent(tcgrp))
+ for (tcgrp = cgrp; tcgrp; tcgrp = cgroup_parent(tcgrp)) {
cgrp->ancestor_ids[tcgrp->level] = tcgrp->id;
+ if (tcgrp != cgrp)
+ tcgrp->nr_descendants++;
+ }
+
if (notify_on_release(parent))
set_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
@@ -4252,6 +4760,29 @@ out_free_cgrp:
return ERR_PTR(ret);
}
+static bool cgroup_check_hierarchy_limits(struct cgroup *parent)
+{
+ struct cgroup *cgroup;
+ int ret = false;
+ int level = 1;
+
+ lockdep_assert_held(&cgroup_mutex);
+
+ for (cgroup = parent; cgroup; cgroup = cgroup_parent(cgroup)) {
+ if (cgroup->nr_descendants >= cgroup->max_descendants)
+ goto fail;
+
+ if (level > cgroup->max_depth)
+ goto fail;
+
+ level++;
+ }
+
+ ret = true;
+fail:
+ return ret;
+}
+
int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name, umode_t mode)
{
struct cgroup *parent, *cgrp;
@@ -4266,6 +4797,11 @@ int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name, umode_t mode)
if (!parent)
return -ENODEV;
+ if (!cgroup_check_hierarchy_limits(parent)) {
+ ret = -EAGAIN;
+ goto out_unlock;
+ }
+
cgrp = cgroup_create(parent);
if (IS_ERR(cgrp)) {
ret = PTR_ERR(cgrp);
@@ -4417,6 +4953,7 @@ static void kill_css(struct cgroup_subsys_state *css)
static int cgroup_destroy_locked(struct cgroup *cgrp)
__releases(&cgroup_mutex) __acquires(&cgroup_mutex)
{
+ struct cgroup *tcgrp, *parent = cgroup_parent(cgrp);
struct cgroup_subsys_state *css;
struct cgrp_cset_link *link;
int ssid;
@@ -4461,7 +4998,15 @@ static int cgroup_destroy_locked(struct cgroup *cgrp)
*/
kernfs_remove(cgrp->kn);
- cgroup1_check_for_release(cgroup_parent(cgrp));
+ if (parent && cgroup_is_threaded(cgrp))
+ parent->nr_threaded_children--;
+
+ for (tcgrp = cgroup_parent(cgrp); tcgrp; tcgrp = cgroup_parent(tcgrp)) {
+ tcgrp->nr_descendants--;
+ tcgrp->nr_dying_descendants++;
+ }
+
+ cgroup1_check_for_release(parent);
/* put the base reference */
percpu_ref_kill(&cgrp->self.refcnt);
@@ -4656,11 +5201,17 @@ int __init cgroup_init(void)
cgrp_dfl_root.subsys_mask |= 1 << ss->id;
+ /* implicit controllers must be threaded too */
+ WARN_ON(ss->implicit_on_dfl && !ss->threaded);
+
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->threaded)
+ cgrp_dfl_threaded_ss_mask |= 1 << ss->id;
+
if (ss->dfl_cftypes == ss->legacy_cftypes) {
WARN_ON(cgroup_add_cftypes(ss, ss->dfl_cftypes));
} else {
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index e7485786db9b..67230ecf2ce1 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -301,6 +301,16 @@ static DECLARE_WORK(cpuset_hotplug_work, cpuset_hotplug_workfn);
static DECLARE_WAIT_QUEUE_HEAD(cpuset_attach_wq);
/*
+ * Cgroup v2 behavior is used when on default hierarchy or the
+ * cgroup_v2_mode flag is set.
+ */
+static inline bool is_in_v2_mode(void)
+{
+ return cgroup_subsys_on_dfl(cpuset_cgrp_subsys) ||
+ (cpuset_cgrp_subsys.root->flags & CGRP_ROOT_CPUSET_V2_MODE);
+}
+
+/*
* This is ugly, but preserves the userspace API for existing cpuset
* users. If someone tries to mount the "cpuset" filesystem, we
* silently switch it to mount "cgroup" instead
@@ -490,8 +500,7 @@ static int validate_change(struct cpuset *cur, struct cpuset *trial)
/* On legacy hiearchy, we must be a subset of our parent cpuset. */
ret = -EACCES;
- if (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) &&
- !is_cpuset_subset(trial, par))
+ if (!is_in_v2_mode() && !is_cpuset_subset(trial, par))
goto out;
/*
@@ -870,7 +879,7 @@ static void update_tasks_cpumask(struct cpuset *cs)
struct css_task_iter it;
struct task_struct *task;
- css_task_iter_start(&cs->css, &it);
+ css_task_iter_start(&cs->css, 0, &it);
while ((task = css_task_iter_next(&it)))
set_cpus_allowed_ptr(task, cs->effective_cpus);
css_task_iter_end(&it);
@@ -904,8 +913,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct cpumask *new_cpus)
* If it becomes empty, inherit the effective mask of the
* parent, which is guaranteed to have some CPUs.
*/
- if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys) &&
- cpumask_empty(new_cpus))
+ if (is_in_v2_mode() && cpumask_empty(new_cpus))
cpumask_copy(new_cpus, parent->effective_cpus);
/* Skip the whole subtree if the cpumask remains the same. */
@@ -922,7 +930,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct cpumask *new_cpus)
cpumask_copy(cp->effective_cpus, new_cpus);
spin_unlock_irq(&callback_lock);
- WARN_ON(!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) &&
+ WARN_ON(!is_in_v2_mode() &&
!cpumask_equal(cp->cpus_allowed, cp->effective_cpus));
update_tasks_cpumask(cp);
@@ -1100,7 +1108,7 @@ static void update_tasks_nodemask(struct cpuset *cs)
* It's ok if we rebind the same mm twice; mpol_rebind_mm()
* is idempotent. Also migrate pages in each mm to new nodes.
*/
- css_task_iter_start(&cs->css, &it);
+ css_task_iter_start(&cs->css, 0, &it);
while ((task = css_task_iter_next(&it))) {
struct mm_struct *mm;
bool migrate;
@@ -1158,8 +1166,7 @@ static void update_nodemasks_hier(struct cpuset *cs, nodemask_t *new_mems)
* If it becomes empty, inherit the effective mask of the
* parent, which is guaranteed to have some MEMs.
*/
- if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys) &&
- nodes_empty(*new_mems))
+ if (is_in_v2_mode() && nodes_empty(*new_mems))
*new_mems = parent->effective_mems;
/* Skip the whole subtree if the nodemask remains the same. */
@@ -1176,7 +1183,7 @@ static void update_nodemasks_hier(struct cpuset *cs, nodemask_t *new_mems)
cp->effective_mems = *new_mems;
spin_unlock_irq(&callback_lock);
- WARN_ON(!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) &&
+ WARN_ON(!is_in_v2_mode() &&
!nodes_equal(cp->mems_allowed, cp->effective_mems));
update_tasks_nodemask(cp);
@@ -1293,7 +1300,7 @@ static void update_tasks_flags(struct cpuset *cs)
struct css_task_iter it;
struct task_struct *task;
- css_task_iter_start(&cs->css, &it);
+ css_task_iter_start(&cs->css, 0, &it);
while ((task = css_task_iter_next(&it)))
cpuset_update_task_spread_flag(cs, task);
css_task_iter_end(&it);
@@ -1468,7 +1475,7 @@ static int cpuset_can_attach(struct cgroup_taskset *tset)
/* allow moving tasks into an empty cpuset if on default hierarchy */
ret = -ENOSPC;
- if (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) &&
+ if (!is_in_v2_mode() &&
(cpumask_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed)))
goto out_unlock;
@@ -1987,7 +1994,7 @@ static int cpuset_css_online(struct cgroup_subsys_state *css)
cpuset_inc();
spin_lock_irq(&callback_lock);
- if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys)) {
+ if (is_in_v2_mode()) {
cpumask_copy(cs->effective_cpus, parent->effective_cpus);
cs->effective_mems = parent->effective_mems;
}
@@ -2064,7 +2071,7 @@ static void cpuset_bind(struct cgroup_subsys_state *root_css)
mutex_lock(&cpuset_mutex);
spin_lock_irq(&callback_lock);
- if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys)) {
+ if (is_in_v2_mode()) {
cpumask_copy(top_cpuset.cpus_allowed, cpu_possible_mask);
top_cpuset.mems_allowed = node_possible_map;
} else {
@@ -2258,7 +2265,7 @@ retry:
cpus_updated = !cpumask_equal(&new_cpus, cs->effective_cpus);
mems_updated = !nodes_equal(new_mems, cs->effective_mems);
- if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys))
+ if (is_in_v2_mode())
hotplug_update_tasks(cs, &new_cpus, &new_mems,
cpus_updated, mems_updated);
else
@@ -2289,7 +2296,7 @@ static void cpuset_hotplug_workfn(struct work_struct *work)
static cpumask_t new_cpus;
static nodemask_t new_mems;
bool cpus_updated, mems_updated;
- bool on_dfl = cgroup_subsys_on_dfl(cpuset_cgrp_subsys);
+ bool on_dfl = is_in_v2_mode();
mutex_lock(&cpuset_mutex);
diff --git a/kernel/cgroup/debug.c b/kernel/cgroup/debug.c
index dac46af22782..f661b4cc5efd 100644
--- a/kernel/cgroup/debug.c
+++ b/kernel/cgroup/debug.c
@@ -114,27 +114,49 @@ static int cgroup_css_links_read(struct seq_file *seq, void *v)
{
struct cgroup_subsys_state *css = seq_css(seq);
struct cgrp_cset_link *link;
- int dead_cnt = 0, extra_refs = 0;
+ int dead_cnt = 0, extra_refs = 0, threaded_csets = 0;
spin_lock_irq(&css_set_lock);
+
list_for_each_entry(link, &css->cgroup->cset_links, cset_link) {
struct css_set *cset = link->cset;
struct task_struct *task;
int count = 0;
int refcnt = refcount_read(&cset->refcount);
- seq_printf(seq, " %d", refcnt);
- if (refcnt - cset->nr_tasks > 0) {
- int extra = refcnt - cset->nr_tasks;
-
- seq_printf(seq, " +%d", extra);
- /*
- * Take out the one additional reference in
- * init_css_set.
- */
- if (cset == &init_css_set)
- extra--;
- extra_refs += extra;
+ /*
+ * Print out the proc_cset and threaded_cset relationship
+ * and highlight difference between refcount and task_count.
+ */
+ seq_printf(seq, "css_set %pK", cset);
+ if (rcu_dereference_protected(cset->dom_cset, 1) != cset) {
+ threaded_csets++;
+ seq_printf(seq, "=>%pK", cset->dom_cset);
+ }
+ if (!list_empty(&cset->threaded_csets)) {
+ struct css_set *tcset;
+ int idx = 0;
+
+ list_for_each_entry(tcset, &cset->threaded_csets,
+ threaded_csets_node) {
+ seq_puts(seq, idx ? "," : "<=");
+ seq_printf(seq, "%pK", tcset);
+ idx++;
+ }
+ } else {
+ seq_printf(seq, " %d", refcnt);
+ if (refcnt - cset->nr_tasks > 0) {
+ int extra = refcnt - cset->nr_tasks;
+
+ seq_printf(seq, " +%d", extra);
+ /*
+ * Take out the one additional reference in
+ * init_css_set.
+ */
+ if (cset == &init_css_set)
+ extra--;
+ extra_refs += extra;
+ }
}
seq_puts(seq, "\n");
@@ -163,10 +185,12 @@ static int cgroup_css_links_read(struct seq_file *seq, void *v)
}
spin_unlock_irq(&css_set_lock);
- if (!dead_cnt && !extra_refs)
+ if (!dead_cnt && !extra_refs && !threaded_csets)
return 0;
seq_puts(seq, "\n");
+ if (threaded_csets)
+ seq_printf(seq, "threaded css_sets = %d\n", threaded_csets);
if (extra_refs)
seq_printf(seq, "extra references = %d\n", extra_refs);
if (dead_cnt)
@@ -352,6 +376,7 @@ static int __init enable_cgroup_debug(char *str)
{
debug_cgrp_subsys.dfl_cftypes = debug_files;
debug_cgrp_subsys.implicit_on_dfl = true;
+ debug_cgrp_subsys.threaded = true;
return 1;
}
__setup("cgroup_debug", enable_cgroup_debug);
diff --git a/kernel/cgroup/freezer.c b/kernel/cgroup/freezer.c
index 1b72d56edce5..08236798d173 100644
--- a/kernel/cgroup/freezer.c
+++ b/kernel/cgroup/freezer.c
@@ -268,7 +268,7 @@ static void update_if_frozen(struct cgroup_subsys_state *css)
rcu_read_unlock();
/* are all tasks frozen? */
- css_task_iter_start(css, &it);
+ css_task_iter_start(css, 0, &it);
while ((task = css_task_iter_next(&it))) {
if (freezing(task)) {
@@ -320,7 +320,7 @@ static void freeze_cgroup(struct freezer *freezer)
struct css_task_iter it;
struct task_struct *task;
- css_task_iter_start(&freezer->css, &it);
+ css_task_iter_start(&freezer->css, 0, &it);
while ((task = css_task_iter_next(&it)))
freeze_task(task);
css_task_iter_end(&it);
@@ -331,7 +331,7 @@ static void unfreeze_cgroup(struct freezer *freezer)
struct css_task_iter it;
struct task_struct *task;
- css_task_iter_start(&freezer->css, &it);
+ css_task_iter_start(&freezer->css, 0, &it);
while ((task = css_task_iter_next(&it)))
__thaw_task(task);
css_task_iter_end(&it);
diff --git a/kernel/cgroup/pids.c b/kernel/cgroup/pids.c
index 2237201d66d5..9829c67ebc0a 100644
--- a/kernel/cgroup/pids.c
+++ b/kernel/cgroup/pids.c
@@ -345,4 +345,5 @@ struct cgroup_subsys pids_cgrp_subsys = {
.free = pids_free,
.legacy_cftypes = pids_files,
.dfl_cftypes = pids_files,
+ .threaded = true,
};
diff --git a/kernel/events/core.c b/kernel/events/core.c
index fb415e3d824b..3e691b75b2db 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -11293,5 +11293,6 @@ struct cgroup_subsys perf_event_cgrp_subsys = {
* controller is not mounted on a legacy hierarchy.
*/
.implicit_on_dfl = true,
+ .threaded = true,
};
#endif /* CONFIG_CGROUP_PERF */
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index ad15850ee157..6532b219b222 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -919,7 +919,7 @@ int mem_cgroup_scan_tasks(struct mem_cgroup *memcg,
struct css_task_iter it;
struct task_struct *task;
- css_task_iter_start(&iter->css, &it);
+ css_task_iter_start(&iter->css, 0, &it);
while (!ret && (task = css_task_iter_next(&it)))
ret = fn(task, arg);
css_task_iter_end(&it);
diff --git a/net/core/netclassid_cgroup.c b/net/core/netclassid_cgroup.c
index 029a61ac6cdd..5e4f04004a49 100644
--- a/net/core/netclassid_cgroup.c
+++ b/net/core/netclassid_cgroup.c
@@ -100,7 +100,7 @@ static int write_classid(struct cgroup_subsys_state *css, struct cftype *cft,
cs->classid = (u32)value;
- css_task_iter_start(css, &it);
+ css_task_iter_start(css, 0, &it);
while ((p = css_task_iter_next(&it))) {
task_lock(p);
iterate_fd(p->files, 0, update_classid_sock,
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-27 03:49:03 +0100