[PATCH -next] cgroup: switch to css_is_online() helper

[PATCH -next] cgroup: switch to css_is_online() helper

[Chen Ridong]

From: Chen Ridong <chenridong@huawei.com>

Use the new css_is_online() helper that has been introduced to check css
online state, instead of testing the CSS_ONLINE flag directly. This
improves readability and centralizes the state check logic.

No functional changes intended.

Signed-off-by: Chen Ridong <chenridong@huawei.com>
---
 fs/fs-writeback.c          | 2 +-
 include/linux/memcontrol.h | 2 +-
 kernel/cgroup/cgroup.c     | 4 ++--
 mm/memcontrol.c            | 2 +-
 mm/page_owner.c            | 2 +-
 5 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 6800886c4d10..5dd6e89a6d29 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -981,7 +981,7 @@ void wbc_account_cgroup_owner(struct writeback_control *wbc, struct folio *folio
 
 	css = mem_cgroup_css_from_folio(folio);
 	/* dead cgroups shouldn't contribute to inode ownership arbitration */
-	if (!(css->flags & CSS_ONLINE))
+	if (!css_is_online(css))
 		return;
 
 	id = css->id;
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 0651865a4564..6a48398a1f4e 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -893,7 +893,7 @@ static inline bool mem_cgroup_online(struct mem_cgroup *memcg)
 {
 	if (mem_cgroup_disabled())
 		return true;
-	return !!(memcg->css.flags & CSS_ONLINE);
+	return css_is_online(&memcg->css);
 }
 
 void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 1e4033d05c29..ad0a35721dff 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -4939,7 +4939,7 @@ bool css_has_online_children(struct cgroup_subsys_state *css)
 
 	rcu_read_lock();
 	css_for_each_child(child, css) {
-		if (child->flags & CSS_ONLINE) {
+		if (css_is_online(child)) {
 			ret = true;
 			break;
 		}
@@ -5744,7 +5744,7 @@ static void offline_css(struct cgroup_subsys_state *css)
 
 	lockdep_assert_held(&cgroup_mutex);
 
-	if (!(css->flags & CSS_ONLINE))
+	if (!css_is_online(css))
 		return;
 
 	if (ss->css_offline)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index be810c1fbfc3..e2e49f4ec9e0 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -281,7 +281,7 @@ ino_t page_cgroup_ino(struct page *page)
 	/* page_folio() is racy here, but the entire function is racy anyway */
 	memcg = folio_memcg_check(page_folio(page));
 
-	while (memcg && !(memcg->css.flags & CSS_ONLINE))
+	while (memcg && !css_is_online(&memcg->css))
 		memcg = parent_mem_cgroup(memcg);
 	if (memcg)
 		ino = cgroup_ino(memcg->css.cgroup);
diff --git a/mm/page_owner.c b/mm/page_owner.c
index a70245684206..27d19f01009c 100644
--- a/mm/page_owner.c
+++ b/mm/page_owner.c
@@ -530,7 +530,7 @@ static inline int print_page_owner_memcg(char *kbuf, size_t count, int ret,
 	if (!memcg)
 		goto out_unlock;
 
-	online = (memcg->css.flags & CSS_ONLINE);
+	online = css_is_online(&memcg->css);
 	cgroup_name(memcg->css.cgroup, name, sizeof(name));
 	ret += scnprintf(kbuf + ret, count - ret,
 			"Charged %sto %smemcg %s\n",
-- 
2.34.1

Re: [PATCH -next] cgroup: switch to css_is_online() helper

[Jan Kara]

On Tue 02-12-25 02:57:47, Chen Ridong wrote:
> From: Chen Ridong <chenridong@huawei.com>
> 
> Use the new css_is_online() helper that has been introduced to check css
> online state, instead of testing the CSS_ONLINE flag directly. This
> improves readability and centralizes the state check logic.
> 
> No functional changes intended.
> 
> Signed-off-by: Chen Ridong <chenridong@huawei.com>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  fs/fs-writeback.c          | 2 +-
>  include/linux/memcontrol.h | 2 +-
>  kernel/cgroup/cgroup.c     | 4 ++--
>  mm/memcontrol.c            | 2 +-
>  mm/page_owner.c            | 2 +-
>  5 files changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
> index 6800886c4d10..5dd6e89a6d29 100644
> --- a/fs/fs-writeback.c
> +++ b/fs/fs-writeback.c
> @@ -981,7 +981,7 @@ void wbc_account_cgroup_owner(struct writeback_control *wbc, struct folio *folio
>  
>  	css = mem_cgroup_css_from_folio(folio);
>  	/* dead cgroups shouldn't contribute to inode ownership arbitration */
> -	if (!(css->flags & CSS_ONLINE))
> +	if (!css_is_online(css))
>  		return;
>  
>  	id = css->id;
> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> index 0651865a4564..6a48398a1f4e 100644
> --- a/include/linux/memcontrol.h
> +++ b/include/linux/memcontrol.h
> @@ -893,7 +893,7 @@ static inline bool mem_cgroup_online(struct mem_cgroup *memcg)
>  {
>  	if (mem_cgroup_disabled())
>  		return true;
> -	return !!(memcg->css.flags & CSS_ONLINE);
> +	return css_is_online(&memcg->css);
>  }
>  
>  void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
> diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
> index 1e4033d05c29..ad0a35721dff 100644
> --- a/kernel/cgroup/cgroup.c
> +++ b/kernel/cgroup/cgroup.c
> @@ -4939,7 +4939,7 @@ bool css_has_online_children(struct cgroup_subsys_state *css)
>  
>  	rcu_read_lock();
>  	css_for_each_child(child, css) {
> -		if (child->flags & CSS_ONLINE) {
> +		if (css_is_online(child)) {
>  			ret = true;
>  			break;
>  		}
> @@ -5744,7 +5744,7 @@ static void offline_css(struct cgroup_subsys_state *css)
>  
>  	lockdep_assert_held(&cgroup_mutex);
>  
> -	if (!(css->flags & CSS_ONLINE))
> +	if (!css_is_online(css))
>  		return;
>  
>  	if (ss->css_offline)
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index be810c1fbfc3..e2e49f4ec9e0 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -281,7 +281,7 @@ ino_t page_cgroup_ino(struct page *page)
>  	/* page_folio() is racy here, but the entire function is racy anyway */
>  	memcg = folio_memcg_check(page_folio(page));
>  
> -	while (memcg && !(memcg->css.flags & CSS_ONLINE))
> +	while (memcg && !css_is_online(&memcg->css))
>  		memcg = parent_mem_cgroup(memcg);
>  	if (memcg)
>  		ino = cgroup_ino(memcg->css.cgroup);
> diff --git a/mm/page_owner.c b/mm/page_owner.c
> index a70245684206..27d19f01009c 100644
> --- a/mm/page_owner.c
> +++ b/mm/page_owner.c
> @@ -530,7 +530,7 @@ static inline int print_page_owner_memcg(char *kbuf, size_t count, int ret,
>  	if (!memcg)
>  		goto out_unlock;
>  
> -	online = (memcg->css.flags & CSS_ONLINE);
> +	online = css_is_online(&memcg->css);
>  	cgroup_name(memcg->css.cgroup, name, sizeof(name));
>  	ret += scnprintf(kbuf + ret, count - ret,
>  			"Charged %sto %smemcg %s\n",
> -- 
> 2.34.1
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

Re: [PATCH -next] cgroup: switch to css_is_online() helper

[Chen Ridong]

On 2025/12/2 19:01, Jan Kara wrote:
> On Tue 02-12-25 02:57:47, Chen Ridong wrote:
>> From: Chen Ridong <chenridong@huawei.com>
>>
>> Use the new css_is_online() helper that has been introduced to check css
>> online state, instead of testing the CSS_ONLINE flag directly. This
>> improves readability and centralizes the state check logic.
>>
>> No functional changes intended.
>>
>> Signed-off-by: Chen Ridong <chenridong@huawei.com>
> 
> Looks good. Feel free to add:
> 
> Reviewed-by: Jan Kara <jack@suse.cz>
> 
> 								Honza
> 

Thank you.

-- 
Best regards,
Ridong

Re: [PATCH -next] cgroup: switch to css_is_online() helper

[Zi Yan]

On 1 Dec 2025, at 21:57, Chen Ridong wrote:

> From: Chen Ridong <chenridong@huawei.com>
>
> Use the new css_is_online() helper that has been introduced to check css
> online state, instead of testing the CSS_ONLINE flag directly. This
> improves readability and centralizes the state check logic.
>
> No functional changes intended.
>
> Signed-off-by: Chen Ridong <chenridong@huawei.com>
> ---
>  fs/fs-writeback.c          | 2 +-
>  include/linux/memcontrol.h | 2 +-
>  kernel/cgroup/cgroup.c     | 4 ++--
>  mm/memcontrol.c            | 2 +-
>  mm/page_owner.c            | 2 +-
>  5 files changed, 6 insertions(+), 6 deletions(-)
>
LGTM. Reviewed-by: Zi Yan <ziy@nvidia.com>

Best Regards,
Yan, Zi

Re: [PATCH -next] cgroup: switch to css_is_online() helper

[Shakeel Butt]

On Tue, Dec 02, 2025 at 02:57:47AM +0000, Chen Ridong wrote:
> From: Chen Ridong <chenridong@huawei.com>
> 
> Use the new css_is_online() helper that has been introduced to check css
> online state, instead of testing the CSS_ONLINE flag directly. This
> improves readability and centralizes the state check logic.
> 
> No functional changes intended.
> 
> Signed-off-by: Chen Ridong <chenridong@huawei.com>

Acked-by: Shakeel Butt <shakeel.butt@linux.dev>