linux-kernel - [PATCH 2/4] mm/migration: remove unneeded lock page and PageMovable check

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Message-ID: <20220409073846.22286-3-linmiaohe@huawei.com>
Date:   Sat, 9 Apr 2022 15:38:44 +0800
From:   Miaohe Lin <linmiaohe@...wei.com>
To:     <akpm@...ux-foundation.org>
CC:     <mike.kravetz@...cle.com>, <shy828301@...il.com>,
        <willy@...radead.org>, <ying.huang@...el.com>, <ziy@...dia.com>,
        <minchan@...nel.org>, <apopple@...dia.com>,
        <dave.hansen@...ux.intel.com>, <o451686892@...il.com>,
        <jhubbard@...dia.com>, <peterx@...hat.com>,
        <naoya.horiguchi@....com>, <mhocko@...e.com>, <riel@...hat.com>,
        <osalvador@...e.de>, <david@...hat.com>, <sfr@...b.auug.org.au>,
        <linux-mm@...ck.org>, <linux-kernel@...r.kernel.org>,
        <linmiaohe@...wei.com>
Subject: [PATCH 2/4] mm/migration: remove unneeded lock page and PageMovable check

When non-lru movable page was freed from under us, __ClearPageMovable must
have been done. Even if it's not done, ClearPageIsolated here won't hurt
as page will be freed anyway. So we can thus remove unneeded lock page and
PageMovable check here.

Signed-off-by: Miaohe Lin <linmiaohe@...wei.com>
---
 mm/migrate.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/mm/migrate.c b/mm/migrate.c
index d8aae6c75990..381963231a62 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1098,12 +1098,8 @@ static int unmap_and_move(new_page_t get_new_page,
 		/* page was freed from under us. So we are done. */
 		ClearPageActive(page);
 		ClearPageUnevictable(page);
-		if (unlikely(__PageMovable(page))) {
-			lock_page(page);
-			if (!PageMovable(page))
-				ClearPageIsolated(page);
-			unlock_page(page);
-		}
+		if (unlikely(__PageMovable(page)))
+			ClearPageIsolated(page);
 		goto out;
 	}
 
-- 
2.23.0