diff options
| author | Oleg Nesterov <oleg@redhat.com> | 2024-06-17 16:31:52 +0200 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2024-06-19 19:18:41 +0200 |
| commit | 6fe960147e08e931dda1ef325dc69320e544aa73 (patch) | |
| tree | 53886297790fccbbd59f6a59026bd52447b83a90 /kernel/cgroup | |
| parent | cgroup/cpuset: Optimize isolated partition only generate_sched_domains() calls (diff) | |
| download | linux-6fe960147e08e931dda1ef325dc69320e544aa73.tar.xz linux-6fe960147e08e931dda1ef325dc69320e544aa73.zip | |
cgroup: avoid the unnecessary list_add(dying_tasks) in cgroup_exit()
cgroup_exit() needs to do this only if the exiting task is a leader and it
is not the last live thread. The patch doesn't use delay_group_leader(),
atomic_read(signal->live) matches the code css_task_iter_advance() more.
cgroup_release() can now check list_empty(task->cg_list) before it takes
css_set_lock and calls ss_set_skip_task_iters().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel/cgroup')
| -rw-r--r-- | kernel/cgroup/cgroup.c | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 4abd817b0c7c..ff3c14fa62e6 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -6701,8 +6701,10 @@ void cgroup_exit(struct task_struct *tsk) WARN_ON_ONCE(list_empty(&tsk->cg_list)); cset = task_css_set(tsk); css_set_move_task(tsk, cset, NULL, false); - list_add_tail(&tsk->cg_list, &cset->dying_tasks); cset->nr_tasks--; + /* matches the signal->live check in css_task_iter_advance() */ + if (thread_group_leader(tsk) && atomic_read(&tsk->signal->live)) + list_add_tail(&tsk->cg_list, &cset->dying_tasks); if (dl_task(tsk)) dec_dl_tasks_cs(tsk); @@ -6729,10 +6731,12 @@ void cgroup_release(struct task_struct *task) ss->release(task); } while_each_subsys_mask(); - spin_lock_irq(&css_set_lock); - css_set_skip_task_iters(task_css_set(task), task); - list_del_init(&task->cg_list); - spin_unlock_irq(&css_set_lock); + if (!list_empty(&task->cg_list)) { + spin_lock_irq(&css_set_lock); + css_set_skip_task_iters(task_css_set(task), task); + list_del_init(&task->cg_list); + spin_unlock_irq(&css_set_lock); + } } void cgroup_free(struct task_struct *task) |