+ khugepaged-fix-wrong-result-value-for-trace_mm_collapse_huge_page_isolate.patch added to -mm tree

+ khugepaged-fix-wrong-result-value-for-trace_mm_collapse_huge_page_isolate.patch added to -mm tree

[akpm]

The patch titled
     Subject: khugepaged: fix wrong result value for trace_mm_collapse_huge_page_isolate()
has been added to the -mm tree.  Its filename is
     khugepaged-fix-wrong-result-value-for-trace_mm_collapse_huge_page_isolate.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/khugepaged-fix-wrong-result-value-for-trace_mm_collapse_huge_page_isolate.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/khugepaged-fix-wrong-result-value-for-trace_mm_collapse_huge_page_isolate.patch

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------------------------------------------------------
From: Miaohe Lin <linmiaohe@huawei.com>
Subject: khugepaged: fix wrong result value for trace_mm_collapse_huge_page_isolate()

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 <linmiaohe@huawei.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/khugepaged.c |   18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

--- a/mm/khugepaged.c~khugepaged-fix-wrong-result-value-for-trace_mm_collapse_huge_page_isolate
+++ a/mm/khugepaged.c
@@ -716,17 +716,17 @@ next:
 		if (pte_write(pteval))
 			writable = true;
 	}
-	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, compound_pagelist);
 	trace_mm_collapse_huge_page_isolate(page, none_or_zero,
_

Patches currently in -mm which might be from linmiaohe@huawei.com are

hugetlb_cgroup-fix-imbalanced-css_get-and-css_put-pair-for-shared-mappings.patch
mm-hugetlb-remove-redundant-reservation-check-condition-in-alloc_huge_page.patch
mm-hugetlb-use-some-helper-functions-to-cleanup-code.patch
mm-hugetlb-optimize-the-surplus-state-transfer-code-in-move_hugetlb_state.patch
hugetlb_cgroup-remove-unnecessary-vm_bug_on_page-in-hugetlb_cgroup_migrate.patch
mm-hugetlb-simplify-the-code-when-alloc_huge_page-failed-in-hugetlb_no_page.patch
mm-hugetlb-avoid-calculating-fault_mutex_hash-in-truncate_op-case.patch
khugepaged-remove-unneeded-return-value-of-khugepaged_collapse_pte_mapped_thps.patch
khugepaged-reuse-the-smp_wmb-inside-__setpageuptodate.patch
khugepaged-use-helper-khugepaged_test_exit-in-__khugepaged_enter.patch
khugepaged-fix-wrong-result-value-for-trace_mm_collapse_huge_page_isolate.patch