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From:   Miaohe Lin <linmiaohe@huawei.com>
To:     <akpm@linux-foundation.org>
CC:     <ying.huang@intel.com>, <songmuchun@bytedance.com>,
        <hch@infradead.org>, <willy@infradead.org>, <linux-mm@kvack.org>,
        <linux-kernel@vger.kernel.org>, <linmiaohe@huawei.com>
Subject: [PATCH v2 6/9] mm/vmscan: take all base pages of THP into account when race with speculative reference
Date:   Sat, 9 Apr 2022 17:34:57 +0800
Message-ID: <20220409093500.10329-7-linmiaohe@huawei.com>
In-Reply-To: <20220409093500.10329-1-linmiaohe@huawei.com>
References: <20220409093500.10329-1-linmiaohe@huawei.com>
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If the page has buffers, shrink_page_list will try to free the buffer
mappings associated with the page and try to free the page as well.
In the rare race with speculative reference, the page will be freed
shortly by speculative reference. But nr_reclaimed is not incremented
correctly when we come across the THP. We need to account all the base
pages in this case.

Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
---
 mm/vmscan.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index cc1193e320c2..53f1d0755b34 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1878,7 +1878,7 @@ static unsigned int shrink_page_list(struct list_head *page_list,
 					 * increment nr_reclaimed here (and
 					 * leave it off the LRU).
 					 */
-					nr_reclaimed++;
+					nr_reclaimed += nr_pages;
 					continue;
 				}
 			}
-- 
2.23.0