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

Tejun Heo
2025-10-29T06:19:21Z

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.

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().
--
2.51.1