linux-kernel - [PATCH 3/3] khugepaged: remove meaningless !pte_present() check in khugepaged_scan

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Date:   Thu, 25 Mar 2021 09:56:47 -0400
From:   Miaohe Lin <linmiaohe@...wei.com>
To:     <akpm@...ux-foundation.org>
CC:     <linux-kernel@...r.kernel.org>, <linux-mm@...ck.org>,
        <linmiaohe@...wei.com>
Subject: [PATCH 3/3] khugepaged: remove meaningless !pte_present() check in khugepaged_scan_pmd()

We know it must meet the !is_swap_pte() and !pte_none() condition if we
reach here. Since !is_swap_pte() indicates pte_none() or pte_present()
is met, it's guaranteed that pte must be present here.

Signed-off-by: Miaohe Lin <linmiaohe@...wei.com>
---
 mm/khugepaged.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 58466af69e70..01c2d0ed9abd 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -1271,10 +1271,6 @@ static int khugepaged_scan_pmd(struct mm_struct *mm,
 				goto out_unmap;
 			}
 		}
-		if (!pte_present(pteval)) {
-			result = SCAN_PTE_NON_PRESENT;
-			goto out_unmap;
-		}
 		if (pte_uffd_wp(pteval)) {
 			/*
 			 * Don't collapse the page if any of the small
-- 
2.19.1