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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Thu, 15 Aug 2019 18:14:16 +0200
Subject: [PATCH 1/4] cgroup: Remove ->css_rstat_flush()
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.4/older/patches-5.4.17-rt8.tar.xz
I was looking at the lifetime of the the ->css_rstat_flush() to see if
cgroup_rstat_cpu_lock should remain a raw_spinlock_t. I didn't find any
users and is unused since it was introduced in commit
8f53470bab042 ("cgroup: Add cgroup_subsys->css_rstat_flush()")
Remove the css_rstat_flush callback because it has no users.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
include/linux/cgroup-defs.h | 5 -----
kernel/cgroup/cgroup.c | 12 ------------
kernel/cgroup/rstat.c | 10 +---------
3 files changed, 1 insertion(+), 26 deletions(-)
--- a/include/linux/cgroup-defs.h
+++ b/include/linux/cgroup-defs.h
@@ -144,9 +144,6 @@ struct cgroup_subsys_state {
struct list_head sibling;
struct list_head children;
- /* flush target list anchored at cgrp->rstat_css_list */
- struct list_head rstat_css_node;
-
/*
* PI: Subsys-unique ID. 0 is unused and root is always 1. The
* matching css can be looked up using css_from_id().
@@ -455,7 +452,6 @@ struct cgroup {
/* per-cpu recursive resource statistics */
struct cgroup_rstat_cpu __percpu *rstat_cpu;
- struct list_head rstat_css_list;
/* cgroup basic resource statistics */
struct cgroup_base_stat pending_bstat; /* pending from children */
@@ -633,7 +629,6 @@ struct cgroup_subsys {
void (*css_released)(struct cgroup_subsys_state *css);
void (*css_free)(struct cgroup_subsys_state *css);
void (*css_reset)(struct cgroup_subsys_state *css);
- void (*css_rstat_flush)(struct cgroup_subsys_state *css, int cpu);
int (*css_extra_stat_show)(struct seq_file *seq,
struct cgroup_subsys_state *css);
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -1957,7 +1957,6 @@ static void init_cgroup_housekeeping(str
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)
@@ -5013,12 +5012,6 @@ static void css_release_work_fn(struct w
list_del_rcu(&css->sibling);
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);
@@ -5080,7 +5073,6 @@ static void init_and_link_css(struct cgr
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);
@@ -5089,9 +5081,6 @@ static void init_and_link_css(struct cgr
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));
}
@@ -5193,7 +5182,6 @@ static struct cgroup_subsys_state *css_c
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);
--- a/kernel/cgroup/rstat.c
+++ b/kernel/cgroup/rstat.c
@@ -162,17 +162,9 @@ static void cgroup_rstat_flush_locked(st
struct cgroup *pos = NULL;
raw_spin_lock(cpu_lock);
- while ((pos = cgroup_rstat_cpu_pop_updated(pos, cgrp, cpu))) {
- struct cgroup_subsys_state *css;
-
+ while ((pos = cgroup_rstat_cpu_pop_updated(pos, cgrp, cpu)))
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 */
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