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authorTejun Heo <tj@kernel.org>2018-04-26 14:29:05 -0700
committerTejun Heo <tj@kernel.org>2018-04-26 14:29:05 -0700
commit8f53470bab04229e93ff9e4c20338cc08b42b344 (patch)
tree8ab616e9b6ee8b2affcbe88278961d5e8bdc7eb3 /kernel/cgroup
parent0fa294fb1985c06c4e3325e30e759d4ca580f59a (diff)
downloadlinux-8f53470bab04229e93ff9e4c20338cc08b42b344.tar.bz2
cgroup: Add cgroup_subsys->css_rstat_flush()
This patch adds cgroup_subsys->css_rstat_flush(). If a subsystem has this callback, its csses are linked on cgrp->css_rstat_list and rstat will call the function whenever the associated cgroup is flushed. Flush is also performed when such csses are released so that residual counts aren't lost. Combined with the rstat API previous patches factored out, this allows controllers to plug into rstat to manage their statistics in a scalable way. Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel/cgroup')
-rw-r--r--kernel/cgroup/cgroup.c11
-rw-r--r--kernel/cgroup/rstat.c11
2 files changed, 21 insertions, 1 deletions
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 31af98996692..04b7e7fad31a 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -1860,6 +1860,7 @@ 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)
@@ -4621,6 +4622,11 @@ static void css_release_work_fn(struct work_struct *work)
if (ss) {
/* css release path */
+ if (!list_empty(&css->rstat_css_node)) {
+ cgroup_rstat_flush(cgrp);
+ list_del_rcu(&css->rstat_css_node);
+ }
+
cgroup_idr_replace(&ss->css_idr, NULL, css->id);
if (ss->css_released)
ss->css_released(css);
@@ -4682,6 +4688,7 @@ 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_node);
css->serial_nr = css_serial_nr_next++;
atomic_set(&css->online_cnt, 0);
@@ -4690,6 +4697,9 @@ static void init_and_link_css(struct cgroup_subsys_state *css,
css_get(css->parent);
}
+ if (cgroup_on_dfl(cgrp) && ss->css_rstat_flush)
+ list_add_rcu(&css->rstat_css_node, &cgrp->rstat_css_list);
+
BUG_ON(cgroup_css(cgrp, ss));
}
@@ -4791,6 +4801,7 @@ static struct cgroup_subsys_state *css_create(struct cgroup *cgrp,
err_list_del:
list_del_rcu(&css->sibling);
err_free_css:
+ list_del_rcu(&css->rstat_css_node);
INIT_RCU_WORK(&css->destroy_rwork, css_free_rwork_fn);
queue_rcu_work(cgroup_destroy_wq, &css->destroy_rwork);
return ERR_PTR(err);
diff --git a/kernel/cgroup/rstat.c b/kernel/cgroup/rstat.c
index 3386fb251a9e..339366e257d4 100644
--- a/kernel/cgroup/rstat.c
+++ b/kernel/cgroup/rstat.c
@@ -145,8 +145,17 @@ static void cgroup_rstat_flush_locked(struct cgroup *cgrp, bool may_sleep)
struct cgroup *pos = NULL;
raw_spin_lock(cpu_lock);
- while ((pos = cgroup_rstat_cpu_pop_updated(pos, cgrp, cpu)))
+ while ((pos = cgroup_rstat_cpu_pop_updated(pos, cgrp, cpu))) {
+ struct cgroup_subsys_state *css;
+
cgroup_base_stat_flush(pos, cpu);
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(css, &pos->rstat_css_list,
+ rstat_css_node)
+ css->ss->css_rstat_flush(css, cpu);
+ rcu_read_unlock();
+ }
raw_spin_unlock(cpu_lock);
/* if @may_sleep, play nice and yield if necessary */