Hello, Prateek.
On Fri, Dec 15, 2017 at 02:24:55PM +0530, Prateek Sood wrote:
> Following are two ways to improve cgroup_transfer_tasks(). In
> both cases task in PF_EXITING state would be left in source
> cgroup. It would be removed from cgroup_exit() in exit path.
>
> diff --git a/kernel/cgroup/cgroup-v1.c b/kernel/cgroup/cgroup-v1.c
> index 024085d..e2bdcdb 100644
> --- a/kernel/cgroup/cgroup-v1.c
> +++ b/kernel/cgroup/cgroup-v1.c
> @@ -123,7 +123,10 @@ int cgroup_transfer_tasks(struct cgroup *to, struct
> cgroup *from)
> */
> do {
> css_task_iter_start(&from->self, 0, &it);
> - task = css_task_iter_next(&it);
> + do {
> + task = css_task_iter_next(&it);
> + } while (task && (task & PF_EXITING))
> +
Yeah, this looks good to me. We can't just make a single pass as in
the other one because we can race aginst fork. And PF_EXITING being
left behind is what was happening previously too anyway. They can't
be moved.
Thanks.
--
tejun
