On Mon 17-06-19 00:13:47, Tetsuo Handa wrote:
[...]
> >From 415e52cf55bc4ad931e4f005421b827f0b02693d Mon Sep 17 00:00:00 2001
> From: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
> Date: Mon, 17 Jun 2019 00:09:38 +0900
> Subject: [PATCH] mm: memcontrol: Use CSS_TASK_ITER_PROCS at mem_cgroup_scan_tasks().
>
> Since commit c03cd7738a83b137 ("cgroup: Include dying leaders with live
> threads in PROCS iterations") corrected how CSS_TASK_ITER_PROCS works,
> mem_cgroup_scan_tasks() can use CSS_TASK_ITER_PROCS in order to check
> only one thread from each thread group.
O(Threads#) is definitely much worse than O(proc#)
> Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Thanks!
> ---
> mm/memcontrol.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index ba9138a..b09ff45 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -1163,7 +1163,7 @@ int mem_cgroup_scan_tasks(struct mem_cgroup *memcg,
> struct css_task_iter it;
> struct task_struct *task;
>
> - css_task_iter_start(&iter->css, 0, &it);
> + css_task_iter_start(&iter->css, CSS_TASK_ITER_PROCS, &it);
> while (!ret && (task = css_task_iter_next(&it)))
> ret = fn(task, arg);
> css_task_iter_end(&it);
> --
> 1.8.3.1
--
Michal Hocko
SUSE Labs
