On Thu 07-01-16 22:31:32, Tetsuo Handa wrote: [...] > I think we need to filter at select_bad_process() and oom_kill_process(). > > When P has no children, P is chosen and TIF_MEMDIE is set on P. But P can > be chosen forever due to P->signal->oom_score_adj == OOM_SCORE_ADJ_MAX > even if the OOM reaper reclaimed P's mm. We need to ensure that > oom_kill_process() is not called with P if P already has TIF_MEMDIE. Hmm. Any task is allowed to set its oom_score_adj that way and I guess we should really make sure that at least sysrq+f will make some progress. This is what I would do. Again I think this is worth a separate patch. Unless there are any objections I will roll out what I have and post 3 separate patches. --- diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 45e51ad2f7cf..ee34a51bd65a 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -333,6 +333,14 @@ static struct task_struct *select_bad_process(struct oom_control *oc, if (points == chosen_points && thread_group_leader(chosen)) continue; + /* + * If the current major task is already ooom killed and this + * is sysrq+f request then we rather choose somebody else + * because the current oom victim might be stuck. + */ + if (is_sysrq_oom(sc) && test_tsk_thread_flag(p, TIF_MEMDIE)) + continue; + chosen = p; chosen_points = points; } -- Michal Hocko SUSE Labs -- 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>