linux-kernel - [PATCH 2/6] hugetlbfs: fix cannot migrate the fallocated HugeTLB page

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Date:   Mon,  4 Jan 2021 14:58:39 +0800
From:   Muchun Song <songmuchun@...edance.com>
To:     mike.kravetz@...cle.com, akpm@...ux-foundation.org
Cc:     hillf.zj@...baba-inc.com, n-horiguchi@...jp.nec.com,
        ak@...ux.intel.com, yongjun_wei@...ndmicro.com.cn, mhocko@...e.cz,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        Muchun Song <songmuchun@...edance.com>
Subject: [PATCH 2/6] hugetlbfs: fix cannot migrate the fallocated HugeTLB page

Because we only can isolate a active page via isolate_huge_page()
and hugetlbfs_fallocate() forget to mark it as active, we cannot
isolate and migrate those pages.

Fixes: 70c3547e36f5 (hugetlbfs: add hugetlbfs_fallocate())
Signed-off-by: Muchun Song <songmuchun@...edance.com>
---
 fs/hugetlbfs/inode.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index b5c109703daa..2aceb085d202 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -737,10 +737,11 @@ static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset,
 
 		/*
 		 * unlock_page because locked by add_to_page_cache()
-		 * page_put due to reference from alloc_huge_page()
+		 * put_page() (which is in the putback_active_hugepage())
+		 * due to reference from alloc_huge_page()
 		 */
 		unlock_page(page);
-		put_page(page);
+		putback_active_hugepage(page);
 	}
 
 	if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size)
-- 
2.11.0