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authorLinus Torvalds <torvalds@linux-foundation.org>2021-11-02 15:37:27 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-11-02 15:37:27 -0700
commita85373fe446adb37cab7b2702f054af1b275dc13 (patch)
treee8feb9cc3a7f95bdae6e05d94d6b7d812356b41a /kernel
parent4075409c9fcbc4b7967f2e92d808acc0b441d92e (diff)
parent588e5d8766486e52ee332a4bb097b016a355b465 (diff)
downloadlinux-a85373fe446adb37cab7b2702f054af1b275dc13.tar.bz2
Merge branch 'for-5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup updates from Tejun Heo: - The misc controller now reports allocation rejections through misc.events instead of printking - cgroup_mutex usage is reduced to improve scalability of some operations - vhost helper threads are now assigned to the right cgroup on cgroup2 - Bug fixes * 'for-5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: bpf: Move wrapper for __cgroup_bpf_*() to kernel/bpf/cgroup.c cgroup: Fix rootcg cpu.stat guest double counting cgroup: no need for cgroup_mutex for /proc/cgroups cgroup: remove cgroup_mutex from cgroupstats_build cgroup: reduce dependency on cgroup_mutex cgroup: cgroup-v1: do not exclude cgrp_dfl_root cgroup: Make rebind_subsystems() disable v2 controllers all at once docs/cgroup: add entry for misc.events misc_cgroup: remove error log to avoid log flood misc_cgroup: introduce misc.events to count failures
Diffstat (limited to 'kernel')
-rw-r--r--kernel/bpf/cgroup.c54
-rw-r--r--kernel/cgroup/cgroup-v1.c17
-rw-r--r--kernel/cgroup/cgroup.c120
-rw-r--r--kernel/cgroup/misc.c31
-rw-r--r--kernel/cgroup/rstat.c2
5 files changed, 129 insertions, 95 deletions
diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index 03145d45e3d5..2ca643af9a54 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -430,10 +430,10 @@ static struct bpf_prog_list *find_attach_entry(struct list_head *progs,
* Exactly one of @prog or @link can be non-null.
* Must be called with cgroup_mutex held.
*/
-int __cgroup_bpf_attach(struct cgroup *cgrp,
- struct bpf_prog *prog, struct bpf_prog *replace_prog,
- struct bpf_cgroup_link *link,
- enum bpf_attach_type type, u32 flags)
+static int __cgroup_bpf_attach(struct cgroup *cgrp,
+ struct bpf_prog *prog, struct bpf_prog *replace_prog,
+ struct bpf_cgroup_link *link,
+ enum bpf_attach_type type, u32 flags)
{
u32 saved_flags = (flags & (BPF_F_ALLOW_OVERRIDE | BPF_F_ALLOW_MULTI));
struct bpf_prog *old_prog = NULL;
@@ -523,6 +523,20 @@ cleanup:
return err;
}
+static int cgroup_bpf_attach(struct cgroup *cgrp,
+ struct bpf_prog *prog, struct bpf_prog *replace_prog,
+ struct bpf_cgroup_link *link,
+ enum bpf_attach_type type,
+ u32 flags)
+{
+ int ret;
+
+ mutex_lock(&cgroup_mutex);
+ ret = __cgroup_bpf_attach(cgrp, prog, replace_prog, link, type, flags);
+ mutex_unlock(&cgroup_mutex);
+ return ret;
+}
+
/* Swap updated BPF program for given link in effective program arrays across
* all descendant cgroups. This function is guaranteed to succeed.
*/
@@ -672,14 +686,14 @@ static struct bpf_prog_list *find_detach_entry(struct list_head *progs,
* propagate the change to descendants
* @cgrp: The cgroup which descendants to traverse
* @prog: A program to detach or NULL
- * @prog: A link to detach or NULL
+ * @link: A link to detach or NULL
* @type: Type of detach operation
*
* At most one of @prog or @link can be non-NULL.
* Must be called with cgroup_mutex held.
*/
-int __cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog,
- struct bpf_cgroup_link *link, enum bpf_attach_type type)
+static int __cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog,
+ struct bpf_cgroup_link *link, enum bpf_attach_type type)
{
enum cgroup_bpf_attach_type atype;
struct bpf_prog *old_prog;
@@ -730,9 +744,20 @@ cleanup:
return err;
}
+static int cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog,
+ enum bpf_attach_type type)
+{
+ int ret;
+
+ mutex_lock(&cgroup_mutex);
+ ret = __cgroup_bpf_detach(cgrp, prog, NULL, type);
+ mutex_unlock(&cgroup_mutex);
+ return ret;
+}
+
/* Must be called with cgroup_mutex held to avoid races. */
-int __cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr,
- union bpf_attr __user *uattr)
+static int __cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr,
+ union bpf_attr __user *uattr)
{
__u32 __user *prog_ids = u64_to_user_ptr(attr->query.prog_ids);
enum bpf_attach_type type = attr->query.attach_type;
@@ -789,6 +814,17 @@ int __cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr,
return ret;
}
+static int cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr,
+ union bpf_attr __user *uattr)
+{
+ int ret;
+
+ mutex_lock(&cgroup_mutex);
+ ret = __cgroup_bpf_query(cgrp, attr, uattr);
+ mutex_unlock(&cgroup_mutex);
+ return ret;
+}
+
int cgroup_bpf_prog_attach(const union bpf_attr *attr,
enum bpf_prog_type ptype, struct bpf_prog *prog)
{
diff --git a/kernel/cgroup/cgroup-v1.c b/kernel/cgroup/cgroup-v1.c
index 35b920328344..81c9e0685948 100644
--- a/kernel/cgroup/cgroup-v1.c
+++ b/kernel/cgroup/cgroup-v1.c
@@ -63,9 +63,6 @@ int cgroup_attach_task_all(struct task_struct *from, struct task_struct *tsk)
for_each_root(root) {
struct cgroup *from_cgrp;
- if (root == &cgrp_dfl_root)
- continue;
-
spin_lock_irq(&css_set_lock);
from_cgrp = task_cgroup_from_root(from, root);
spin_unlock_irq(&css_set_lock);
@@ -662,11 +659,9 @@ int proc_cgroupstats_show(struct seq_file *m, void *v)
seq_puts(m, "#subsys_name\thierarchy\tnum_cgroups\tenabled\n");
/*
- * ideally we don't want subsystems moving around while we do this.
- * cgroup_mutex is also necessary to guarantee an atomic snapshot of
- * subsys/hierarchy state.
+ * Grab the subsystems state racily. No need to add avenue to
+ * cgroup_mutex contention.
*/
- mutex_lock(&cgroup_mutex);
for_each_subsys(ss, i)
seq_printf(m, "%s\t%d\t%d\t%d\n",
@@ -674,7 +669,6 @@ int proc_cgroupstats_show(struct seq_file *m, void *v)
atomic_read(&ss->root->nr_cgrps),
cgroup_ssid_enabled(i));
- mutex_unlock(&cgroup_mutex);
return 0;
}
@@ -701,8 +695,6 @@ int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry)
kernfs_type(kn) != KERNFS_DIR)
return -EINVAL;
- mutex_lock(&cgroup_mutex);
-
/*
* We aren't being called from kernfs and there's no guarantee on
* @kn->priv's validity. For this and css_tryget_online_from_dir(),
@@ -710,9 +702,8 @@ int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry)
*/
rcu_read_lock();
cgrp = rcu_dereference(*(void __rcu __force **)&kn->priv);
- if (!cgrp || cgroup_is_dead(cgrp)) {
+ if (!cgrp || !cgroup_tryget(cgrp)) {
rcu_read_unlock();
- mutex_unlock(&cgroup_mutex);
return -ENOENT;
}
rcu_read_unlock();
@@ -740,7 +731,7 @@ int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry)
}
css_task_iter_end(&it);
- mutex_unlock(&cgroup_mutex);
+ cgroup_put(cgrp);
return 0;
}
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index ea08f01d0111..919194de39c8 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -1740,6 +1740,7 @@ int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask)
struct cgroup *dcgrp = &dst_root->cgrp;
struct cgroup_subsys *ss;
int ssid, i, ret;
+ u16 dfl_disable_ss_mask = 0;
lockdep_assert_held(&cgroup_mutex);
@@ -1756,8 +1757,28 @@ int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask)
/* can't move between two non-dummy roots either */
if (ss->root != &cgrp_dfl_root && dst_root != &cgrp_dfl_root)
return -EBUSY;
+
+ /*
+ * Collect ssid's that need to be disabled from default
+ * hierarchy.
+ */
+ if (ss->root == &cgrp_dfl_root)
+ dfl_disable_ss_mask |= 1 << ssid;
+
} while_each_subsys_mask();
+ if (dfl_disable_ss_mask) {
+ struct cgroup *scgrp = &cgrp_dfl_root.cgrp;
+
+ /*
+ * Controllers from default hierarchy that need to be rebound
+ * are all disabled together in one go.
+ */
+ cgrp_dfl_root.subsys_mask &= ~dfl_disable_ss_mask;
+ WARN_ON(cgroup_apply_control(scgrp));
+ cgroup_finalize_control(scgrp, 0);
+ }
+
do_each_subsys_mask(ss, ssid, ss_mask) {
struct cgroup_root *src_root = ss->root;
struct cgroup *scgrp = &src_root->cgrp;
@@ -1766,10 +1787,12 @@ int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask)
WARN_ON(!css || cgroup_css(dcgrp, ss));
- /* disable from the source */
- src_root->subsys_mask &= ~(1 << ssid);
- WARN_ON(cgroup_apply_control(scgrp));
- cgroup_finalize_control(scgrp, 0);
+ if (src_root != &cgrp_dfl_root) {
+ /* disable from the source */
+ src_root->subsys_mask &= ~(1 << ssid);
+ WARN_ON(cgroup_apply_control(scgrp));
+ cgroup_finalize_control(scgrp, 0);
+ }
/* rebind */
RCU_INIT_POINTER(scgrp->subsys[ssid], NULL);
@@ -5911,17 +5934,20 @@ struct cgroup *cgroup_get_from_id(u64 id)
struct kernfs_node *kn;
struct cgroup *cgrp = NULL;
- mutex_lock(&cgroup_mutex);
kn = kernfs_find_and_get_node_by_id(cgrp_dfl_root.kf_root, id);
if (!kn)
- goto out_unlock;
+ goto out;
- cgrp = kn->priv;
- if (cgroup_is_dead(cgrp) || !cgroup_tryget(cgrp))
+ rcu_read_lock();
+
+ cgrp = rcu_dereference(*(void __rcu __force **)&kn->priv);
+ if (cgrp && !cgroup_tryget(cgrp))
cgrp = NULL;
+
+ rcu_read_unlock();
+
kernfs_put(kn);
-out_unlock:
- mutex_unlock(&cgroup_mutex);
+out:
return cgrp;
}
EXPORT_SYMBOL_GPL(cgroup_get_from_id);
@@ -6474,30 +6500,34 @@ struct cgroup_subsys_state *css_from_id(int id, struct cgroup_subsys *ss)
*
* Find the cgroup at @path on the default hierarchy, increment its
* reference count and return it. Returns pointer to the found cgroup on
- * success, ERR_PTR(-ENOENT) if @path doesn't exist and ERR_PTR(-ENOTDIR)
- * if @path points to a non-directory.
+ * success, ERR_PTR(-ENOENT) if @path doesn't exist or if the cgroup has already
+ * been released and ERR_PTR(-ENOTDIR) if @path points to a non-directory.
*/
struct cgroup *cgroup_get_from_path(const char *path)
{
struct kernfs_node *kn;
- struct cgroup *cgrp;
-
- mutex_lock(&cgroup_mutex);
+ struct cgroup *cgrp = ERR_PTR(-ENOENT);
kn = kernfs_walk_and_get(cgrp_dfl_root.cgrp.kn, path);
- if (kn) {
- if (kernfs_type(kn) == KERNFS_DIR) {
- cgrp = kn->priv;
- cgroup_get_live(cgrp);
- } else {
- cgrp = ERR_PTR(-ENOTDIR);
- }
- kernfs_put(kn);
- } else {
- cgrp = ERR_PTR(-ENOENT);
+ if (!kn)
+ goto out;
+
+ if (kernfs_type(kn) != KERNFS_DIR) {
+ cgrp = ERR_PTR(-ENOTDIR);
+ goto out_kernfs;
}
- mutex_unlock(&cgroup_mutex);
+ rcu_read_lock();
+
+ cgrp = rcu_dereference(*(void __rcu __force **)&kn->priv);
+ if (!cgrp || !cgroup_tryget(cgrp))
+ cgrp = ERR_PTR(-ENOENT);
+
+ rcu_read_unlock();
+
+out_kernfs:
+ kernfs_put(kn);
+out:
return cgrp;
}
EXPORT_SYMBOL_GPL(cgroup_get_from_path);
@@ -6625,44 +6655,6 @@ void cgroup_sk_free(struct sock_cgroup_data *skcd)
#endif /* CONFIG_SOCK_CGROUP_DATA */
-#ifdef CONFIG_CGROUP_BPF
-int cgroup_bpf_attach(struct cgroup *cgrp,
- struct bpf_prog *prog, struct bpf_prog *replace_prog,
- struct bpf_cgroup_link *link,
- enum bpf_attach_type type,
- u32 flags)
-{
- int ret;
-
- mutex_lock(&cgroup_mutex);
- ret = __cgroup_bpf_attach(cgrp, prog, replace_prog, link, type, flags);
- mutex_unlock(&cgroup_mutex);
- return ret;
-}
-
-int cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog,
- enum bpf_attach_type type)
-{
- int ret;
-
- mutex_lock(&cgroup_mutex);
- ret = __cgroup_bpf_detach(cgrp, prog, NULL, type);
- mutex_unlock(&cgroup_mutex);
- return ret;
-}
-
-int cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr,
- union bpf_attr __user *uattr)
-{
- int ret;
-
- mutex_lock(&cgroup_mutex);
- ret = __cgroup_bpf_query(cgrp, attr, uattr);
- mutex_unlock(&cgroup_mutex);
- return ret;
-}
-#endif /* CONFIG_CGROUP_BPF */
-
#ifdef CONFIG_SYSFS
static ssize_t show_delegatable_files(struct cftype *files, char *buf,
ssize_t size, const char *prefix)
diff --git a/kernel/cgroup/misc.c b/kernel/cgroup/misc.c
index ec02d963cad1..fe3e8a0eb7ed 100644
--- a/kernel/cgroup/misc.c
+++ b/kernel/cgroup/misc.c
@@ -157,13 +157,6 @@ int misc_cg_try_charge(enum misc_res_type type, struct misc_cg *cg,
new_usage = atomic_long_add_return(amount, &res->usage);
if (new_usage > READ_ONCE(res->max) ||
new_usage > READ_ONCE(misc_res_capacity[type])) {
- if (!res->failed) {
- pr_info("cgroup: charge rejected by the misc controller for %s resource in ",
- misc_res_name[type]);
- pr_cont_cgroup_path(i->css.cgroup);
- pr_cont("\n");
- res->failed = true;
- }
ret = -EBUSY;
goto err_charge;
}
@@ -171,6 +164,11 @@ int misc_cg_try_charge(enum misc_res_type type, struct misc_cg *cg,
return 0;
err_charge:
+ for (j = i; j; j = parent_misc(j)) {
+ atomic_long_inc(&j->res[type].events);
+ cgroup_file_notify(&j->events_file);
+ }
+
for (j = cg; j != i; j = parent_misc(j))
misc_cg_cancel_charge(type, j, amount);
misc_cg_cancel_charge(type, i, amount);
@@ -335,6 +333,19 @@ static int misc_cg_capacity_show(struct seq_file *sf, void *v)
return 0;
}
+static int misc_events_show(struct seq_file *sf, void *v)
+{
+ struct misc_cg *cg = css_misc(seq_css(sf));
+ unsigned long events, i;
+
+ for (i = 0; i < MISC_CG_RES_TYPES; i++) {
+ events = atomic_long_read(&cg->res[i].events);
+ if (READ_ONCE(misc_res_capacity[i]) || events)
+ seq_printf(sf, "%s.max %lu\n", misc_res_name[i], events);
+ }
+ return 0;
+}
+
/* Misc cgroup interface files */
static struct cftype misc_cg_files[] = {
{
@@ -353,6 +364,12 @@ static struct cftype misc_cg_files[] = {
.seq_show = misc_cg_capacity_show,
.flags = CFTYPE_ONLY_ON_ROOT,
},
+ {
+ .name = "events",
+ .flags = CFTYPE_NOT_ON_ROOT,
+ .file_offset = offsetof(struct misc_cg, events_file),
+ .seq_show = misc_events_show,
+ },
{}
};
diff --git a/kernel/cgroup/rstat.c b/kernel/cgroup/rstat.c
index b264ab5652ba..1486768f2318 100644
--- a/kernel/cgroup/rstat.c
+++ b/kernel/cgroup/rstat.c
@@ -433,8 +433,6 @@ static void root_cgroup_cputime(struct task_cputime *cputime)
cputime->sum_exec_runtime += user;
cputime->sum_exec_runtime += sys;
cputime->sum_exec_runtime += cpustat[CPUTIME_STEAL];
- cputime->sum_exec_runtime += cpustat[CPUTIME_GUEST];
- cputime->sum_exec_runtime += cpustat[CPUTIME_GUEST_NICE];
}
}