Dave Jones wrote: > On Tue, Jul 19, 2016 at 07:52:28PM +0900, Tetsuo Handa wrote: > > On 2016/07/19 8:18, Dave Jones wrote: > > > Whoa. Why did it pick systemd-journal ? > > > > I guess that it is because all trinity processes' mm already had MMF_OOM_REAPED set. > > > > The OOM reaper sets MMF_OOM_REAPED when OOM reap operation succeeded. But > > "[ pid ] uid tgid total_vm rss nr_ptes nr_pmds swapents oom_score_adj name" listing > > includes processes whose mm already has MMF_OOM_REAPED set. As a result, trinity-c15 and > > trinity-c4 are shown again in the listing. While I can't confirm that trinity-c10, trinity-c2, > > trinity-c0 and trinity-c11 are already OOM killed, I guess they are already OOM killed and > > their mm already had MMF_OOM_REAPED set. > > That still doesn't explain why it picked the journal process, instead of waiting until > the previous reaping operation had actually killed those Trinity tasks. I thought your patch did --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -169,6 +169,8 @@ unsigned long oom_badness(struct task_struct *p, struct mem_cgroup *memcg, if (oom_unkillable_task(p, memcg, nodemask)) return 0; + if (!strncmp(p->comm, "trinity-", 8)) + return 0; p = find_lock_task_mm(p); if (!p) to OOM-kill only Trinity tasks. But your patch did not touch OOM victim selection logic. Then, it is completely normal and expected result that systemd-journald was selected because systemd-journald got highest score among all OOM-killable !MMF_OOM_REAPED mm users. Nothing is wrong. By the way, your patch needs to call put_task_struct(p) before return. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>