Re: [PATCH] mm: memcontrol: correct the comment of mem_cgroup_unmark_under_oom()

From: Michal Hocko
Date: Wed Sep 16 2020 - 16:53:14 EST


On Wed 16-09-20 09:19:27, Miaohe Lin wrote:
> Since commit fb2a6fc56be6 ("mm: memcg: rework and document OOM waiting and
> wakeup"), we have renamed mem_cgroup_oom_lock to mem_cgroup_oom_trylock. So
> replace mem_cgroup_oom_lock with mem_cgroup_oom_trylock in comment.

While you are right I find the comment more confusing then helpful.
What does it try to tell us actually? Is it still valid? Shouldn't we
rather remove it or make it more clear?
>
> Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
> ---
> mm/memcontrol.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 3d26b4b954e2..702aa4d7ebbc 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -1846,7 +1846,7 @@ static void mem_cgroup_unmark_under_oom(struct mem_cgroup *memcg)
>
> /*
> * When a new child is created while the hierarchy is under oom,
> - * mem_cgroup_oom_lock() may not be called. Watch for underflow.
> + * mem_cgroup_oom_trylock() may not be called. Watch for underflow.
> */
> spin_lock(&memcg_oom_lock);
> for_each_mem_cgroup_tree(iter, memcg)
> --
> 2.19.1

--
Michal Hocko
SUSE Labs