On Mon, Aug 22, 2022 at 4:48 PM Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > > On Mon, 22 Aug 2022 16:33:51 -0600 Yu Zhao <yuzhao@xxxxxxxxxx> wrote: > > > > --- a/mm/vmscan.c~mm-delete-unused-mmf_oom_victim-flag-fix > > > +++ a/mm/vmscan.c > > > @@ -3429,9 +3429,6 @@ static bool should_skip_mm(struct mm_str > > > if (size < MIN_LRU_BATCH) > > > return true; > > > > > > - if (mm_is_oom_victim(mm)) > > > - return true; > > > - > > > return !mmget_not_zero(mm); > > > } > > > > > > @@ -4127,9 +4124,6 @@ restart: > > > > > > walk_pmd_range(&val, addr, next, args); > > > > > > - if (mm_is_oom_victim(args->mm)) > > > - return 1; > > > - > > > /* a racy check to curtail the waiting time */ > > > if (wq_has_sleeper(&walk->lruvec->mm_state.wait)) > > > return 1; > > > _ > > > > > > Please confirm? > > > > LGTM. The deleted checks are not about correctness. > > OK, for now. > > > I've queued > > > > --- a/mm/vmscan.c > > +++ b/mm/vmscan.c > > @@ -3402,7 +3402,7 @@ static bool should_skip_mm(struct mm_struct *mm, > > struct lru_gen_mm_walk *walk) > > if (size < MIN_LRU_BATCH) > > return true; > > > > - if (mm_is_oom_victim(mm)) > > + if (test_bit(MMF_OOM_REAP_QUEUED, &mm->flags)) > > return true; > > > > return !mmget_not_zero(mm); > > @@ -4109,7 +4109,7 @@ static int walk_pud_range(p4d_t *p4d, unsigned > > long start, unsigned long end, > > > > walk_pmd_range(&val, addr, next, args); > > > > - if (mm_is_oom_victim(args->mm)) > > + if (test_bit(MMF_OOM_REAP_QUEUED, &args->mm->flags)) > > return 1; > > > > /* a racy check to curtail the waiting time */ > > Oh. Why? What does this change do? The MMF_OOM_REAP_QUEUED flag is similar to the deleted MMF_OOM_VICTIM flag, but it's set at a later stage during an OOM kill. When either is set, the OOM reaper is probably already freeing the memory of this mm_struct, or at least it's going to. So there is no need to dwell on it in the reclaim path, hence not about correctness.
