Re: [PATCH v2 1/2] mm, memcg: rename mem_cgroup_out_of_memory()

Michal Hocko
2020-05-04T07:59:07Z

On Mon 04-05-20 00:26:20, Yafang Shao wrote:
> Rename mem_cgroup_out_of_memory() to mem_cgroup_oom_kill() to indicate
> that this function is used to try to kill a process.
> With this change it will cooperate better with the oom events.
> function memcg event
> mem_cgroup_oom() oom
> mem_cgroup_oom_kill() oom_kill
>
> Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
> Reviewed-by: Shakeel Butt <shakeelb@google.com>
> Cc: Johannes Weiner <hannes@cmpxchg.org>
> Cc: Michal Hocko <mhocko@kernel.org>
> Cc: Roman Gushchin <guro@fb.com>
> Cc: Greg Thelen <gthelen@google.com>

Well, I do not have a strong opinion on this. I believe the idea behind
the naming was that this is a memcg counterpart for out_of_memory.
So to be honest I do not consider this an improvement.

> ---
> mm/memcontrol.c | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 5beea03dd58a..985edce98491 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -1570,7 +1570,7 @@ unsigned long mem_cgroup_size(struct mem_cgroup *memcg)
> return page_counter_read(&memcg->memory);
> }
>
> -static bool mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
> +static bool mem_cgroup_oom_kill(struct mem_cgroup *memcg, gfp_t gfp_mask,
> int order)
> {
> struct oom_control oc = {
> @@ -1799,7 +1799,7 @@ static enum oom_status mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int
> * relying on the oom victim to make a forward progress and we can
> * invoke the oom killer here.
> *
> - * Please note that mem_cgroup_out_of_memory might fail to find a
> + * Please note that mem_cgroup_oom_kill might fail to find a
> * victim and then we have to bail out from the charge path.
> */
> if (memcg->oom_kill_disable) {
> @@ -1821,7 +1821,7 @@ static enum oom_status mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int
> mem_cgroup_oom_notify(memcg);
>
> mem_cgroup_unmark_under_oom(memcg);
> - if (mem_cgroup_out_of_memory(memcg, mask, order))
> + if (mem_cgroup_oom_kill(memcg, mask, order))
> ret = OOM_SUCCESS;
> else
> ret = OOM_FAILED;
> @@ -1879,7 +1879,7 @@ bool mem_cgroup_oom_synchronize(bool handle)
> if (locked && !memcg->oom_kill_disable) {
> mem_cgroup_unmark_under_oom(memcg);
> finish_wait(&memcg_oom_waitq, &owait.wait);
> - mem_cgroup_out_of_memory(memcg, current->memcg_oom_gfp_mask,
> + mem_cgroup_oom_kill(memcg, current->memcg_oom_gfp_mask,
> current->memcg_oom_order);
> } else {
> schedule();
> @@ -6102,7 +6102,7 @@ static ssize_t memory_max_write(struct kernfs_open_file *of,
> }
>
> memcg_memory_event(memcg, MEMCG_OOM);
> - if (!mem_cgroup_out_of_memory(memcg, GFP_KERNEL, 0))
> + if (!mem_cgroup_oom_kill(memcg, GFP_KERNEL, 0))
> break;
> }
>
> --
> 2.18.2

--
Michal Hocko
SUSE Labs