[PATCH] cgroup: update comment about dropping cgroup kn refs

[PATCH] cgroup: update comment about dropping cgroup kn refs

[Haorui He]

the cgroup is actually freed in css_free_rwork_fn() now
the ref count of the cgroup's kernfs_node is also dropped there
so we need to update the corresponding comment in cgroup_mkdir()

Signed-off-by: Haorui He <mail@hehaorui.com>
---
 kernel/cgroup/cgroup.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index d9061bd55436..805764cf14e2 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -5835,7 +5835,7 @@ int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name, umode_t mode)
 	}
 
 	/*
-	 * This extra ref will be put in cgroup_free_fn() and guarantees
+	 * This extra ref will be put in css_free_rwork_fn() and guarantees
 	 * that @cgrp->kn is always accessible.
 	 */
 	kernfs_get(cgrp->kn);
-- 
2.47.1

Re: [PATCH] cgroup: update comment about dropping cgroup kn refs

[Michal Koutný]

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Hello Haorui.

On Sun, Jan 12, 2025 at 10:49:20PM +0800, Haorui He <mail@hehaorui.com> wrote:
> the cgroup is actually freed in css_free_rwork_fn() now
> the ref count of the cgroup's kernfs_node is also dropped there
> so we need to update the corresponding comment in cgroup_mkdir()

It seems you've read through the comments recently.
Do you have more up your sleeve? (So that it could be grouped in one
comments changeset.)

Thanks,
Michal

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Re: [PATCH] cgroup: update comment about dropping cgroup kn refs

[Haorui He]

Hello Michal.


On 2025/1/13 21:34, Michal Koutný wrote:
> It seems you've read through the comments recently.
> Do you have more up your sleeve? (So that it could be grouped in one
> comments changeset.)

No, I have not find more right now. I'm just reading the cgroups code 
and happen to be confused by that comment.
I'm still reading about the cgroups code base though, so I'm not sure 
whether I will find more places that need to be updated.

Thanks,
Haorui He

Re: [PATCH] cgroup: update comment about dropping cgroup kn refs

[Tejun Heo]

On Sun, Jan 12, 2025 at 10:49:20PM +0800, Haorui He wrote:
> the cgroup is actually freed in css_free_rwork_fn() now
> the ref count of the cgroup's kernfs_node is also dropped there
> so we need to update the corresponding comment in cgroup_mkdir()
> 
> Signed-off-by: Haorui He <mail@hehaorui.com>

Applied to sched_ext/for-6.14.

Thanks.

-- 
tejun