Re: [PATCH RESEND] mm/oom_kill: don't kill exiting tasks in oom_kill_memcg_member

[Haifeng Xu]

On 2023/3/14 17:19, Michal Hocko wrote:
> On Tue 14-03-23 09:11:36, Haifeng Xu wrote:
>> If oom_group is set, oom_kill_process() invokes oom_kill_memcg_member()
>> to kill all processes in the memcg. When scanning tasks in memcg, maybe
>> the provided task is marked as oom victim. Also, some tasks are likely
>> to release their address space. There is no need to kill the exiting tasks.
> 
> This doesn't state any actual problem. Could you be more specific? Is
> this a bug fix, a behavior change or an optimization?


1) oom_kill_process() has inovked __oom_kill_process() to kill the selected victim, but it will be scanned
in mem_cgroup_scan_tasks(). It's pointless to kill the victim twice. 

2) for those exiting processes, reaping them directly is also a faster way to free memory compare with invoking
__oom_kill_process().