linux-kernel - [PATCH 3/3] mm/memory-failure.c: dissolve truncated hugetlb page

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Date:   Thu, 7 Apr 2022 21:03:52 +0800
From:   Miaohe Lin <linmiaohe@...wei.com>
To:     <akpm@...ux-foundation.org>, <naoya.horiguchi@....com>
CC:     <shy828301@...il.com>, <mike.kravetz@...cle.com>,
        <david@...hat.com>, <linux-mm@...ck.org>,
        <linux-kernel@...r.kernel.org>, <linmiaohe@...wei.com>
Subject: [PATCH 3/3] mm/memory-failure.c: dissolve truncated hugetlb page

If me_huge_page meets a truncated huge page, hpage won't be dissolved
even if we hold the last refcnt. It's because the truncated huge page
has NULL page_mapping while it's not anonymous page too. Thus we lose
the last chance to dissolve it into buddy to save healthy subpages.
Remove PageAnon check to handle these huge pages too.

Signed-off-by: Miaohe Lin <linmiaohe@...wei.com>
---
 mm/memory-failure.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index bd563f47630c..3f054dbb169d 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1046,8 +1046,7 @@ static int me_huge_page(struct page_state *ps, struct page *p)
 		 * hugepage, so we can free and dissolve it into buddy to
 		 * save healthy subpages.
 		 */
-		if (PageAnon(hpage))
-			put_page(hpage);
+		put_page(hpage);
 		if (__page_handle_poison(p)) {
 			page_ref_inc(p);
 			res = MF_RECOVERED;
-- 
2.23.0