Re: Re: [PATCH v2] mm: oom: introduce cpuset oom

[Gang Li <ligang.bdlg@bytedance.com>]

On 2023/4/4 22:31, Michal Hocko wrote:
> [CC cpuset people]
> 
> The oom report should be explicit about this being CPUSET specific oom
> handling so unexpected behavior could be nailed down to this change so I
Yes, the oom message looks like this:

```
[   65.470256] 
oom-kill:constraint=CONSTRAINT_CPUSET,nodemask=(null),cpuset=test,mems_allowed=0,global_oom,task_memcg=/user.slice/user-0.slice/session-4.scope,task=memkiller,pid=1968,uid=0
Apr  4 09:08:53 debian kernel: [   65.481992] Out of memory: Killed 
process 1968 (memkiller) total-vm:2099436kB, anon-rss:1971712kB, 
file-rss:1024kB, shmem-rss:0kB, UID:0 pgtables:3904kB oom_score_adj:0
```


> do not see a major concern from the oom POV. Nevertheless it would be
> still good to consider whether this should be an opt-in behavior. I
> personally do not see a major problem because most cpuset deployments I
> have seen tend to be well partitioned so the new behavior makes more
> sense.
> 

Since memcgroup oom is mandatory, cpuset oom should preferably be 
mandatory as well. But we can still consider adding an option to user.

How about introduce `/proc/sys/vm/oom_in_cpuset`?