There are cases where, if an attempted collapse fails, all subsequent orders are guaranteed to also fail. Avoid these collapse attempts by bailing out early.
Reviewed-by: Lorenzo Stoakes <[email protected]> Acked-by: Usama Arif <[email protected]> Acked-by: David Hildenbrand (Arm) <[email protected]> Signed-off-by: Nico Pache <[email protected]> --- mm/khugepaged.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 430047316f43..7de92b28dd30 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1499,6 +1499,7 @@ static enum scan_result mthp_collapse(struct mm_struct *mm, collapse_address = address + offset * PAGE_SIZE; ret = collapse_huge_page(mm, collapse_address, referenced, unmapped, cc, order); + switch (ret) { /* Cases where we continue to next collapse candidate */ case SCAN_SUCCEED: @@ -1509,6 +1510,18 @@ static enum scan_result mthp_collapse(struct mm_struct *mm, /* Cases where lower orders might still succeed */ case SCAN_ALLOC_HUGE_PAGE_FAIL: alloc_failed = true; + fallthrough; + case SCAN_LACK_REFERENCED_PAGE: + case SCAN_EXCEED_NONE_PTE: + case SCAN_EXCEED_SWAP_PTE: + case SCAN_EXCEED_SHARED_PTE: + case SCAN_PAGE_LOCK: + case SCAN_PAGE_COUNT: + case SCAN_PAGE_NULL: + case SCAN_DEL_PAGE_LRU: + case SCAN_PTE_NON_PRESENT: + case SCAN_PTE_UFFD_WP: + case SCAN_PAGE_LAZYFREE: last_result = ret; goto next_order; /* Cases where no further collapse is possible */ -- 2.54.0
