diff options
| -rw-r--r-- | Documentation/cgroup-v2.txt | 221 | ||||
| -rw-r--r-- | include/linux/cgroup-defs.h | 68 | ||||
| -rw-r--r-- | include/linux/cgroup.h | 39 | ||||
| -rw-r--r-- | kernel/cgroup/cgroup-internal.h | 12 | ||||
| -rw-r--r-- | kernel/cgroup/cgroup-v1.c | 75 | ||||
| -rw-r--r-- | kernel/cgroup/cgroup.c | 947 | ||||
| -rw-r--r-- | kernel/cgroup/cpuset.c | 39 | ||||
| -rw-r--r-- | kernel/cgroup/debug.c | 53 | ||||
| -rw-r--r-- | kernel/cgroup/freezer.c | 6 | ||||
| -rw-r--r-- | kernel/cgroup/pids.c | 1 | ||||
| -rw-r--r-- | kernel/events/core.c | 1 | ||||
| -rw-r--r-- | mm/memcontrol.c | 2 | ||||
| -rw-r--r-- | net/core/netclassid_cgroup.c | 2 |
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 ass |