Re: [PATCH 1/4] cgroup: Rename cgroup lifecycle hooks to cgroup_task_*()

Chen Ridong
2025-10-31T02:25:36Z

On 2025/10/29 14:19, Tejun Heo wrote:
> The current names cgroup_exit(), cgroup_release(), and cgroup_free() are
> confusing because they look like they're operating on cgroups themselves when
> they're actually task lifecycle hooks. For example, cgroup_init() initializes
> the cgroup subsystem while cgroup_exit() is a task exit notification to
> cgroup. Rename them to cgroup_task_exit(), cgroup_task_release(), and
> cgroup_task_free() to make it clear that these operate on tasks.
>

This makes sense.

> Cc: Dan Schatzberg <dschatzberg@meta.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Signed-off-by: Tejun Heo <tj@kernel.org>
> ---
> include/linux/cgroup.h | 12 ++++++------
> kernel/cgroup/cgroup.c | 11 ++++++-----
> kernel/exit.c | 4 ++--
> kernel/fork.c | 2 +-
> kernel/sched/autogroup.c | 4 ++--
> 5 files changed, 17 insertions(+), 16 deletions(-)
>
> diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
> index 6ed477338b16..4068035176c4 100644
> --- a/include/linux/cgroup.h
> +++ b/include/linux/cgroup.h
> @@ -137,9 +137,9 @@ extern void cgroup_cancel_fork(struct task_struct *p,
> struct kernel_clone_args *kargs);
> extern void cgroup_post_fork(struct task_struct *p,
> struct kernel_clone_args *kargs);
> -void cgroup_exit(struct task_struct *p);
> -void cgroup_release(struct task_struct *p);
> -void cgroup_free(struct task_struct *p);
> +void cgroup_task_exit(struct task_struct *p);
> +void cgroup_task_release(struct task_struct *p);
> +void cgroup_task_free(struct task_struct *p);
>
> int cgroup_init_early(void);
> int cgroup_init(void);
> @@ -680,9 +680,9 @@ static inline void cgroup_cancel_fork(struct task_struct *p,
> struct kernel_clone_args *kargs) {}
> static inline void cgroup_post_fork(struct task_struct *p,
> struct kernel_clone_args *kargs) {}
> -static inline void cgroup_exit(struct task_struct *p) {}
> -static inline void cgroup_release(struct task_struct *p) {}
> -static inline void cgroup_free(struct task_struct *p) {}
> +static inline void cgroup_task_exit(struct task_struct *p) {}
> +static inline void cgroup_task_release(struct task_struct *p) {}
> +static inline void cgroup_task_free(struct task_struct *p) {}
>
> static inline int cgroup_init_early(void) { return 0; }
> static inline int cgroup_init(void) { return 0; }
> diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
> index 6ae5f48cf64e..826b7fd2f85d 100644
> --- a/kernel/cgroup/cgroup.c
> +++ b/kernel/cgroup/cgroup.c
> @@ -944,7 +944,8 @@ static void css_set_move_task(struct task_struct *task,
> /*
> * We are synchronized through cgroup_threadgroup_rwsem
> * against PF_EXITING setting such that we can't race
> - * against cgroup_exit()/cgroup_free() dropping the css_set.
> + * against cgroup_task_exit()/cgroup_task_free() dropping
> + * the css_set.
> */
> WARN_ON_ONCE(task->flags & PF_EXITING);
>
> @@ -6972,13 +6973,13 @@ void cgroup_post_fork(struct task_struct *child,
> }
>
> /**
> - * cgroup_exit - detach cgroup from exiting task
> + * cgroup_task_exit - detach cgroup from exiting task
> * @tsk: pointer to task_struct of exiting process
> *
> * Description: Detach cgroup from @tsk.
> *
> */
> -void cgroup_exit(struct task_struct *tsk)
> +void cgroup_task_exit(struct task_struct *tsk)
> {
> struct cgroup_subsys *ss;
> struct css_set *cset;
> @@ -7010,7 +7011,7 @@ void cgroup_exit(struct task_struct *tsk)
> } while_each_subsys_mask();
> }
>
> -void cgroup_release(struct task_struct *task)
> +void cgroup_task_release(struct task_struct *task)
> {
> struct cgroup_subsys *ss;
> int ssid;
> @@ -7027,7 +7028,7 @@ void cgroup_release(struct task_struct *task)
> }
> }
>
> -void cgroup_free(struct task_struct *task)
> +void cgroup_task_free(struct task_struct *task)
> {
> struct css_set *cset = task_css_set(task);
> put_css_set(cset);
> diff --git a/kernel/exit.c b/kernel/exit.c
> index 9f74e8f1c431..46173461e8de 100644
> --- a/kernel/exit.c
> +++ b/kernel/exit.c
> @@ -257,7 +257,7 @@ void release_task(struct task_struct *p)
> rcu_read_unlock();
>
> pidfs_exit(p);
> - cgroup_release(p);
> + cgroup_task_release(p);
>
> /* Retrieve @thread_pid before __unhash_process() may set it to NULL. */
> thread_pid = task_pid(p);
> @@ -967,7 +967,7 @@ void __noreturn do_exit(long code)
> exit_thread(tsk);
>
> sched_autogroup_exit_task(tsk);
> - cgroup_exit(tsk);
> + cgroup_task_exit(tsk);
>
> /*
> * FIXME: do that only when needed, using sched_exit tracepoint
> diff --git a/kernel/fork.c b/kernel/fork.c
> index 3da0f08615a9..960c39c9c264 100644
> --- a/kernel/fork.c
> +++ b/kernel/fork.c
> @@ -738,7 +738,7 @@ void __put_task_struct(struct task_struct *tsk)
> unwind_task_free(tsk);
> sched_ext_free(tsk);
> io_uring_free(tsk);
> - cgroup_free(tsk);
> + cgroup_task_free(tsk);
> task_numa_free(tsk, true);
> security_task_free(tsk);
> exit_creds(tsk);
> diff --git a/kernel/sched/autogroup.c b/kernel/sched/autogroup.c
> index cdea931aae30..954137775f38 100644
> --- a/kernel/sched/autogroup.c
> +++ b/kernel/sched/autogroup.c
> @@ -178,8 +178,8 @@ autogroup_move_group(struct task_struct *p, struct autogroup *ag)
> * this process can already run with task_group() == prev->tg or we can
> * race with cgroup code which can read autogroup = prev under rq->lock.
> * In the latter case for_each_thread() can not miss a migrating thread,
> - * cpu_cgroup_attach() must not be possible after cgroup_exit() and it
> - * can't be removed from thread list, we hold ->siglock.
> + * cpu_cgroup_attach() must not be possible after cgroup_task_exit()
> + * and it can't be removed from thread list, we hold ->siglock.
> *
> * If an exiting thread was already removed from thread list we rely on
> * sched_autogroup_exit_task().

Reviewed-by: Chen Ridong<chenridong@huawei.com>

--
Best regards,
Ridong