On Tue 14-03-23 18:07:42, Haifeng Xu wrote: > > > 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. Why does that matter though? The purpose of task_will_free_mem in oom_kill_process is different. It would bail out from a potentially noisy OOM report when the selected oom victim is expected to terminate soon. __oom_kill_process called for the whole memcg doesn't aim at avoiding any oom victims. It merely sends a kill signal too all of them. > 2) for those exiting processes, reaping them directly is also a faster way to free memory compare with invoking > __oom_kill_process(). Is it? What if the terminating task is blocked on lock? Async oom reaping might release those resources in that case. -- Michal Hocko SUSE Labs
