Move the rstat entities off of the cgroup struct and onto the
cgroup_subsys_state struct. Adjust related code to reflect this new ownership.
Signed-off-by: JP Kobryn <inwardvessel@xxxxxxxxx>
---
include/linux/cgroup-defs.h | 40 ++++++++--------
kernel/cgroup/cgroup.c | 65 ++++++++++++++++++--------
kernel/cgroup/rstat.c | 92 ++++++++++++++++++-------------------
3 files changed, 111 insertions(+), 86 deletions(-)
diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h
index 1b20d2d8ef7c..1932f8ae7995 100644
--- a/include/linux/cgroup-defs.h
+++ b/include/linux/cgroup-defs.h
@@ -180,6 +180,24 @@ struct cgroup_subsys_state {
struct list_head sibling;
struct list_head children;
+ /* per-cpu recursive resource statistics */
+ struct cgroup_rstat_cpu __percpu *rstat_cpu;
+ struct list_head rstat_css_list;
+
+ /*
+ * Add padding to separate the read mostly rstat_cpu and
+ * rstat_css_list into a different cacheline from the following
+ * rstat_flush_next and *bstat fields which can have frequent updates.
+ */
+ CACHELINE_PADDING(_pad_);
+
+ /*
+ * A singly-linked list of cgroup structures to be rstat flushed.
+ * This is a scratch field to be used exclusively by
+ * cgroup_rstat_flush_locked() and protected by cgroup_rstat_lock.
+ */
+ struct cgroup_subsys_state *rstat_flush_next;
+
/* flush target list anchored at cgrp->rstat_css_list */
struct list_head rstat_css_node;
@@ -389,8 +407,8 @@ struct cgroup_rstat_cpu {
*
* Protected by per-cpu cgroup_rstat_cpu_lock.
*/
- struct cgroup *updated_children; /* terminated by self cgroup */
- struct cgroup *updated_next; /* NULL iff not on the list */
+ struct cgroup_subsys_state *updated_children; /* terminated by self cgroup */
+ struct cgroup_subsys_state *updated_next; /* NULL iff not on the list */
};
struct cgroup_freezer_state {
@@ -516,24 +534,6 @@ struct cgroup {
struct cgroup *dom_cgrp;
struct cgroup *old_dom_cgrp; /* used while enabling threaded */
- /* per-cpu recursive resource statistics */
- struct cgroup_rstat_cpu __percpu *rstat_cpu;
- struct list_head rstat_css_list;
-
- /*
- * Add padding to separate the read mostly rstat_cpu and
- * rstat_css_list into a different cacheline from the following
- * rstat_flush_next and *bstat fields which can have frequent updates.
- */
- CACHELINE_PADDING(_pad_);
-
- /*
- * A singly-linked list of cgroup structures to be rstat flushed.
- * This is a scratch field to be used exclusively by
- * cgroup_rstat_flush_locked() and protected by cgroup_rstat_lock.
- */
- struct cgroup *rstat_flush_next;
-
/* cgroup basic resource statistics */
struct cgroup_base_stat last_bstat;
struct cgroup_base_stat bstat;
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 848e09f433c0..96a2d15fe5e9 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -164,7 +164,7 @@ static struct static_key_true *cgroup_subsys_on_dfl_key[] = {
static DEFINE_PER_CPU(struct cgroup_rstat_cpu, cgrp_dfl_root_rstat_cpu);
/* the default hierarchy */
-struct cgroup_root cgrp_dfl_root = { .cgrp.rstat_cpu = &cgrp_dfl_root_rstat_cpu };
+struct cgroup_root cgrp_dfl_root = { .cgrp.self.rstat_cpu = &cgrp_dfl_root_rstat_cpu };
EXPORT_SYMBOL_GPL(cgrp_dfl_root);
/*
@@ -1826,6 +1826,7 @@ int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask)
struct cgroup_root *src_root = ss->root;
struct cgroup *scgrp = &src_root->cgrp;
struct cgroup_subsys_state *css = cgroup_css(scgrp, ss);
+ struct cgroup_subsys_state *dcss = cgroup_css(dcgrp, ss);
struct css_set *cset, *cset_pos;
struct css_task_iter *it;
@@ -1867,7 +1868,7 @@ int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask)
list_del_rcu(&css->rstat_css_node);
synchronize_rcu();
list_add_rcu(&css->rstat_css_node,
- &dcgrp->rstat_css_list);
+ &dcss->rstat_css_list);
}
/* default hierarchy doesn't enable controllers by default */
@@ -2052,7 +2053,6 @@ static void init_cgroup_housekeeping(struct cgroup *cgrp)
cgrp->dom_cgrp = cgrp;
cgrp->max_descendants = INT_MAX;
cgrp->max_depth = INT_MAX;
- INIT_LIST_HEAD(&cgrp->rstat_css_list);
prev_cputime_init(&cgrp->prev_cputime);
for_each_subsys(ss, ssid)
@@ -2088,7 +2088,8 @@ int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask)
struct cgroup *root_cgrp = &root->cgrp;
struct kernfs_syscall_ops *kf_sops;
struct css_set *cset;
- int i, ret;
+ struct cgroup_subsys *ss;
+ int i, ret, ssid;
lockdep_assert_held(&cgroup_mutex);
@@ -2132,10 +2133,6 @@ int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask)
if (ret)
goto destroy_root;
- ret = cgroup_rstat_init(&root_cgrp->self);
- if (ret)
- goto destroy_root;
-
ret = rebind_subsystems(root, ss_mask);
if (ret)
goto exit_stats;
@@ -2174,7 +2171,10 @@ int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask)
goto out;
exit_stats:
- cgroup_rstat_exit(&root_cgrp->self);
+ for_each_subsys(ss, ssid) {
+ struct cgroup_subsys_state *css = init_css_set.subsys[ssid];
+ cgroup_rstat_exit(css);
+ }
destroy_root:
kernfs_destroy_root(root->kf_root);
root->kf_root = NULL;
@@ -3229,6 +3229,10 @@ static int cgroup_apply_control_enable(struct cgroup *cgrp)
int ssid, ret;
cgroup_for_each_live_descendant_pre(dsct, d_css, cgrp) {
+ ret = cgroup_rstat_init(&dsct->self);
+ if (ret)
+ return ret;
+
for_each_subsys(ss, ssid) {
struct cgroup_subsys_state *css = cgroup_css(dsct, ss);
@@ -3239,6 +3243,10 @@ static int cgroup_apply_control_enable(struct cgroup *cgrp)
css = css_create(dsct, ss);
if (IS_ERR(css))
return PTR_ERR(css);
+
+ ret = cgroup_rstat_init(css);
+ if (ret)
+ goto err_free_css;
}
WARN_ON_ONCE(percpu_ref_is_dying(&css->refcnt));
@@ -3252,6 +3260,20 @@ static int cgroup_apply_control_enable(struct cgroup *cgrp)
}
return 0;
+
+err_free_css:
+ cgroup_for_each_live_descendant_pre(dsct, d_css, cgrp) {
+ cgroup_rstat_exit(&dsct->self);
+
+ for_each_subsys(ss, ssid) {
+ struct cgroup_subsys_state *css = cgroup_css(dsct, ss);
+
+ if (css != &dsct->self)
+ cgroup_rstat_exit(css);
+ }
+ }
+
+ return ret;
}
/**
@@ -5403,6 +5425,7 @@ static void css_free_rwork_fn(struct work_struct *work)
struct cgroup_subsys_state, destroy_rwork);
struct cgroup_subsys *ss = css->ss;
struct cgroup *cgrp = css->cgroup;
+ int ssid;
percpu_ref_exit(&css->refcnt);
@@ -5435,7 +5458,12 @@ static void css_free_rwork_fn(struct work_struct *work)
cgroup_put(cgroup_parent(cgrp));
kernfs_put(cgrp->kn);
psi_cgroup_free(cgrp);
- cgroup_rstat_exit(css);
+ for_each_subsys(ss, ssid) {
+ struct cgroup_subsys_state *css = cgrp->subsys[ssid];
+
+ if (css)
+ cgroup_rstat_exit(css);
+ }
kfree(cgrp);
} else {
/*
@@ -5541,6 +5569,7 @@ static void init_and_link_css(struct cgroup_subsys_state *css,
css->id = -1;
INIT_LIST_HEAD(&css->sibling);
INIT_LIST_HEAD(&css->children);
+ INIT_LIST_HEAD(&css->rstat_css_list);
INIT_LIST_HEAD(&css->rstat_css_node);
css->serial_nr = css_serial_nr_next++;
atomic_set(&css->online_cnt, 0);
@@ -5551,7 +5580,7 @@ static void init_and_link_css(struct cgroup_subsys_state *css,
}
if (ss->css_rstat_flush)
- list_add_rcu(&css->rstat_css_node, &cgrp->rstat_css_list);
+ list_add_rcu(&css->rstat_css_node, &css->rstat_css_list);
BUG_ON(cgroup_css(cgrp, ss));
}
@@ -5686,14 +5715,6 @@ static struct cgroup *cgroup_create(struct cgroup *parent, const char *name,
if (ret)
goto out_free_cgrp;
- /* init self cgroup early so css->cgroup is valid within cgroup_rstat_init()
- * note that this will go away in a subsequent patch in this series
- */
- cgrp->self.cgroup = cgrp;
- ret = cgroup_rstat_init(&cgrp->self);
- if (ret)
- goto out_cancel_ref;
-
/* create the directory */
kn = kernfs_create_dir_ns(parent->kn, name, mode,
current_fsuid(), current_fsgid(),
@@ -5784,7 +5805,6 @@ static struct cgroup *cgroup_create(struct cgroup *parent, const char *name,
kernfs_remove(cgrp->kn);
out_stat_exit:
cgroup_rstat_exit(&cgrp->self);
-out_cancel_ref:
percpu_ref_exit(&cgrp->self.refcnt);
out_free_cgrp:
kfree(cgrp);
@@ -6189,6 +6209,8 @@ int __init cgroup_init(void)
cgroup_unlock();
for_each_subsys(ss, ssid) {
+ struct cgroup_subsys_state *css;
+
if (ss->early_init) {
struct cgroup_subsys_state *css =
init_css_set.subsys[ss->id];
@@ -6200,6 +6222,9 @@ int __init cgroup_init(void)
cgroup_init_subsys(ss, false);
}
+ css = init_css_set.subsys[ss->id];
+ BUG_ON(cgroup_rstat_init(css));
+
list_add_tail(&init_css_set.e_cset_node[ssid],
&cgrp_dfl_root.cgrp.e_csets[ssid]);
diff --git a/kernel/cgroup/rstat.c b/kernel/cgroup/rstat.c
index 01a5c185b02a..4381eb9ac426 100644
--- a/kernel/cgroup/rstat.c
+++ b/kernel/cgroup/rstat.c
@@ -14,9 +14,10 @@ static DEFINE_PER_CPU(raw_spinlock_t, cgroup_rstat_cpu_lock);
static void cgroup_base_stat_flush(struct cgroup *cgrp, int cpu);
-static struct cgroup_rstat_cpu *cgroup_rstat_cpu(struct cgroup *cgrp, int cpu)
+static struct cgroup_rstat_cpu *css_rstat_cpu(
+ struct cgroup_subsys_state *css, int cpu)
{
- return per_cpu_ptr(cgrp->rstat_cpu, cpu);
+ return per_cpu_ptr(css->rstat_cpu, cpu);
}
/*
@@ -96,15 +97,16 @@ __bpf_kfunc void cgroup_rstat_updated(struct cgroup_subsys_state *css, int cpu)
* instead of NULL, we can tell whether @cgrp is on the list by
* testing the next pointer for NULL.
*/
- if (data_race(cgroup_rstat_cpu(cgrp, cpu)->updated_next))
+ if (data_race(css_rstat_cpu(css, cpu)->updated_next))
return;
flags = _cgroup_rstat_cpu_lock(cpu_lock, cpu, cgrp, true);
/* put @cgrp and all ancestors on the corresponding updated lists */
while (true) {
- struct cgroup_rstat_cpu *rstatc = cgroup_rstat_cpu(cgrp, cpu);
- struct cgroup *parent = cgroup_parent(cgrp);
+ struct cgroup_rstat_cpu *rstatc = css_rstat_cpu(css, cpu);
+ struct cgroup_subsys_state *parent = css->parent
+;
struct cgroup_rstat_cpu *prstatc;
/*
@@ -116,15 +118,15 @@ __bpf_kfunc void cgroup_rstat_updated(struct cgroup_subsys_state *css, int cpu)
/* Root has no parent to link it to, but mark it busy */
if (!parent) {
- rstatc->updated_next = cgrp;
+ rstatc->updated_next = css;
break;
}
- prstatc = cgroup_rstat_cpu(parent, cpu);
+ prstatc = css_rstat_cpu(parent, cpu);
rstatc->updated_next = prstatc->updated_children;
- prstatc->updated_children = cgrp;
+ prstatc->updated_children = css;
- cgrp = parent;
+ css = parent;
}
_cgroup_rstat_cpu_unlock(cpu_lock, cpu, cgrp, flags, true);
@@ -142,12 +144,13 @@ __bpf_kfunc void cgroup_rstat_updated(struct cgroup_subsys_state *css, int cpu)
* into a singly linked list built from the tail backward like "pushing"
* cgroups into a stack. The root is pushed by the caller.
*/
-static struct cgroup *cgroup_rstat_push_children(struct cgroup *head,
- struct cgroup *child, int cpu)
+static struct cgroup_subsys_state *cgroup_rstat_push_children(
+ struct cgroup_subsys_state *head,
+ struct cgroup_subsys_state *child, int cpu)
{
- struct cgroup *chead = child; /* Head of child cgroup level */
- struct cgroup *ghead = NULL; /* Head of grandchild cgroup level */
- struct cgroup *parent, *grandchild;
+ struct cgroup_subsys_state *chead = child; /* Head of child cgroup level */
+ struct cgroup_subsys_state *ghead = NULL; /* Head of grandchild cgroup level */
+ struct cgroup_subsys_state *parent, *grandchild;
struct cgroup_rstat_cpu *crstatc;
child->rstat_flush_next = NULL;
@@ -156,13 +159,13 @@ static struct cgroup *cgroup_rstat_push_children(struct cgroup *head,
while (chead) {
child = chead;
chead = child->rstat_flush_next;
- parent = cgroup_parent(child);
+ parent = child->parent;
/* updated_next is parent cgroup terminated */
while (child != parent) {
child->rstat_flush_next = head;
head = child;
- crstatc = cgroup_rstat_cpu(child, cpu);
+ crstatc = css_rstat_cpu(child, cpu);
grandchild = crstatc->updated_children;
if (grandchild != child) {
/* Push the grand child to the next level */
@@ -201,16 +204,15 @@ static struct cgroup *cgroup_rstat_push_children(struct cgroup *head,
* within the children list and terminated by the parent cgroup. An exception
* here is the cgroup root whose updated_next can be self terminated.
*/
-static struct cgroup *cgroup_rstat_updated_list(struct cgroup_subsys_state *root_css,
- int cpu)
+static struct cgroup_subsys_state *cgroup_rstat_updated_list(
+ struct cgroup_subsys_state *root, int cpu)
{
- struct cgroup *root = root_css->cgroup;
raw_spinlock_t *cpu_lock = per_cpu_ptr(&cgroup_rstat_cpu_lock, cpu);
- struct cgroup_rstat_cpu *rstatc = cgroup_rstat_cpu(root, cpu);
- struct cgroup *head = NULL, *parent, *child;
+ struct cgroup_rstat_cpu *rstatc = css_rstat_cpu(root, cpu);
+ struct cgroup_subsys_state *head = NULL, *parent, *child;
unsigned long flags;
- flags = _cgroup_rstat_cpu_lock(cpu_lock, cpu, root, false);
+ flags = _cgroup_rstat_cpu_lock(cpu_lock, cpu, root->cgroup, false);
/* Return NULL if this subtree is not on-list */
if (!rstatc->updated_next)
@@ -220,17 +222,17 @@ static struct cgroup *cgroup_rstat_updated_list(struct cgroup_subsys_state *root
* Unlink @root from its parent. As the updated_children list is
* singly linked, we have to walk it to find the removal point.
*/
- parent = cgroup_parent(root);
+ parent = root->parent;
if (parent) {
struct cgroup_rstat_cpu *prstatc;
- struct cgroup **nextp;
+ struct cgroup_subsys_state **nextp;
- prstatc = cgroup_rstat_cpu(parent, cpu);
+ prstatc = css_rstat_cpu(parent, cpu);
nextp = &prstatc->updated_children;
while (*nextp != root) {
struct cgroup_rstat_cpu *nrstatc;
- nrstatc = cgroup_rstat_cpu(*nextp, cpu);
+ nrstatc = css_rstat_cpu(*nextp, cpu);
WARN_ON_ONCE(*nextp == parent);
nextp = &nrstatc->updated_next;
}
@@ -247,7 +249,7 @@ static struct cgroup *cgroup_rstat_updated_list(struct cgroup_subsys_state *root
if (child != root)
head = cgroup_rstat_push_children(head, child, cpu);
unlock_ret:
- _cgroup_rstat_cpu_unlock(cpu_lock, cpu, root, flags, false);
+ _cgroup_rstat_cpu_unlock(cpu_lock, cpu, root->cgroup, flags, false);
return head;
}
@@ -316,13 +318,13 @@ static void cgroup_rstat_flush_locked(struct cgroup_subsys_state *css)
lockdep_assert_held(&cgroup_rstat_lock);
for_each_possible_cpu(cpu) {
- struct cgroup *pos = cgroup_rstat_updated_list(css, cpu);
+ struct cgroup_subsys_state *pos = cgroup_rstat_updated_list(css, cpu);
for (; pos; pos = pos->rstat_flush_next) {
struct cgroup_subsys_state *css_iter;
- cgroup_base_stat_flush(pos, cpu);
- bpf_rstat_flush(pos, cgroup_parent(pos), cpu);
+ cgroup_base_stat_flush(pos->cgroup, cpu);
+ bpf_rstat_flush(pos->cgroup, cgroup_parent(pos->cgroup), cpu);
rcu_read_lock();
list_for_each_entry_rcu(css_iter, &pos->rstat_css_list,
@@ -392,21 +394,20 @@ void cgroup_rstat_flush_release(struct cgroup_subsys_state *css)
int cgroup_rstat_init(struct cgroup_subsys_state *css)
{
- struct cgroup *cgrp = css->cgroup;
int cpu;
- /* the root cgrp has rstat_cpu preallocated */
- if (!cgrp->rstat_cpu) {
- cgrp->rstat_cpu = alloc_percpu(struct cgroup_rstat_cpu);
- if (!cgrp->rstat_cpu)
+ /* the root cgrp css has rstat_cpu preallocated */
+ if (!css->rstat_cpu) {
+ css->rstat_cpu = alloc_percpu(struct cgroup_rstat_cpu);
+ if (!css->rstat_cpu)
return -ENOMEM;
}
/* ->updated_children list is self terminated */
for_each_possible_cpu(cpu) {
- struct cgroup_rstat_cpu *rstatc = cgroup_rstat_cpu(cgrp, cpu);
+ struct cgroup_rstat_cpu *rstatc = css_rstat_cpu(css, cpu);
- rstatc->updated_children = cgrp;
+ rstatc->updated_children = css;
u64_stats_init(&rstatc->bsync);
}
@@ -415,22 +416,21 @@ int cgroup_rstat_init(struct cgroup_subsys_state *css)
void cgroup_rstat_exit(struct cgroup_subsys_state *css)
{
- struct cgroup *cgrp = css->cgroup;
int cpu;
- cgroup_rstat_flush(&cgrp->self);
+ cgroup_rstat_flush(css);
/* sanity check */
for_each_possible_cpu(cpu) {
- struct cgroup_rstat_cpu *rstatc = cgroup_rstat_cpu(cgrp, cpu);
+ struct cgroup_rstat_cpu *rstatc = css_rstat_cpu(css, cpu);
- if (WARN_ON_ONCE(rstatc->updated_children != cgrp) ||
+ if (WARN_ON_ONCE(rstatc->updated_children != css) ||
WARN_ON_ONCE(rstatc->updated_next))
return;
}
- free_percpu(cgrp->rstat_cpu);
- cgrp->rstat_cpu = NULL;
+ free_percpu(css->rstat_cpu);
+ css->rstat_cpu = NULL;
}
void __init cgroup_rstat_boot(void)
@@ -471,7 +471,7 @@ static void cgroup_base_stat_sub(struct cgroup_base_stat *dst_bstat,
static void cgroup_base_stat_flush(struct cgroup *cgrp, int cpu)
{
- struct cgroup_rstat_cpu *rstatc = cgroup_rstat_cpu(cgrp, cpu);
+ struct cgroup_rstat_cpu *rstatc = css_rstat_cpu(&cgrp->self, cpu);
struct cgroup *parent = cgroup_parent(cgrp);
struct cgroup_rstat_cpu *prstatc;
struct cgroup_base_stat delta;
@@ -501,7 +501,7 @@ static void cgroup_base_stat_flush(struct cgroup *cgrp, int cpu)
cgroup_base_stat_add(&cgrp->last_bstat, &delta);
delta = rstatc->subtree_bstat;
- prstatc = cgroup_rstat_cpu(parent, cpu);
+ prstatc = css_rstat_cpu(&parent->self, cpu);
cgroup_base_stat_sub(&delta, &rstatc->last_subtree_bstat);
cgroup_base_stat_add(&prstatc->subtree_bstat, &delta);
cgroup_base_stat_add(&rstatc->last_subtree_bstat, &delta);
@@ -513,7 +513,7 @@ cgroup_base_stat_cputime_account_begin(struct cgroup *cgrp, unsigned long *flags
{
struct cgroup_rstat_cpu *rstatc;
- rstatc = get_cpu_ptr(cgrp->rstat_cpu);
+ rstatc = get_cpu_ptr(cgrp->self.rstat_cpu);
*flags = u64_stats_update_begin_irqsave(&rstatc->bsync);
return rstatc;
}
--
2.47.1
