[PATCH] cgroup: Simplify code in css_set_move_task

From: haifeng.xu
Date: Thu Oct 20 2022 - 03:47:53 EST


Check the populated state of css_set in css_set_update_populated
and update the populated state of to_cset after from_cset is updated.

Signed-off-by: haifeng.xu <haifeng.xu@xxxxxxxxxx>
---
kernel/cgroup/cgroup.c | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index d922773fa90b..6c474be57f91 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -861,7 +861,8 @@ static void css_set_update_populated(struct css_set *cset, bool populated)
{
struct cgrp_cset_link *link;

- lockdep_assert_held(&css_set_lock);
+ if (!cset || css_set_populated(cset))
+ return;

list_for_each_entry(link, &cset->cgrp_links, cgrp_link)
cgroup_update_populated(link->cgrp, populated);
@@ -903,16 +904,12 @@ static void css_set_move_task(struct task_struct *task,
{
lockdep_assert_held(&css_set_lock);

- if (to_cset && !css_set_populated(to_cset))
- css_set_update_populated(to_cset, true);
-
if (from_cset) {
WARN_ON_ONCE(list_empty(&task->cg_list));

css_set_skip_task_iters(from_cset, task);
list_del_init(&task->cg_list);
- if (!css_set_populated(from_cset))
- css_set_update_populated(from_cset, false);
+ css_set_update_populated(from_cset, false);
} else {
WARN_ON_ONCE(!list_empty(&task->cg_list));
}
@@ -926,6 +923,7 @@ static void css_set_move_task(struct task_struct *task,
WARN_ON_ONCE(task->flags & PF_EXITING);

cgroup_move_task(task, to_cset);
+ css_set_update_populated(to_cset, true);
list_add_tail(&task->cg_list, use_mg_tasks ? &to_cset->mg_tasks :
&to_cset->tasks);
}
--
2.25.1