From d5e95afdd84931b2c41b24a7ac41899d87aab297 Mon Sep 17 00:00:00 2001 From: Miaohe Lin Date: Tue, 4 May 2021 18:33:46 -0700 Subject: [PATCH] khugepaged: fix wrong result value for trace_mm_collapse_huge_page_isolate() [ Upstream commit 74e579bf231a337ab3786d59e64bc94f45ca7b3f ] In writable and !referenced case, the result value should be SCAN_LACK_REFERENCED_PAGE for trace_mm_collapse_huge_page_isolate() instead of default 0 (SCAN_FAIL) here. Link: https://lkml.kernel.org/r/20210306032947.35921-5-linmiaohe@huawei.com Fixes: 7d2eba0557c1 ("mm: add tracepoint for scanning pages") Signed-off-by: Miaohe Lin Acked-by: Kirill A. Shutemov Cc: Dan Carpenter Cc: Ebru Akagunduz Cc: Mike Kravetz Cc: Rik van Riel Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- mm/khugepaged.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 753b0e2fef36..0f1bdbae45e2 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -596,17 +596,17 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma, mmu_notifier_test_young(vma->vm_mm, address)) referenced++; } - if (likely(writable)) { - if (likely(referenced)) { - result = SCAN_SUCCEED; - trace_mm_collapse_huge_page_isolate(page, none_or_zero, - referenced, writable, result); - return 1; - } - } else { + + if (unlikely(!writable)) { result = SCAN_PAGE_RO; + } else if (unlikely(!referenced)) { + result = SCAN_LACK_REFERENCED_PAGE; + } else { + result = SCAN_SUCCEED; + trace_mm_collapse_huge_page_isolate(page, none_or_zero, + referenced, writable, result); + return 1; } - out: release_pte_pages(pte, _pte); trace_mm_collapse_huge_page_isolate(page, none_or_zero, -- 2.20.1