On Mon, Aug 22, 2022 at 4:48 PM Andrew Morton akpm@linux-foundation.org wrote:
On Mon, 22 Aug 2022 16:33:51 -0600 Yu Zhao yuzhao@google.com 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.