linux-kernel - [PATCH v3 4/6] mm/vmscan: take all base pages of THP into account when race with speculative reference

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Message-ID: <20220425111232.23182-5-linmiaohe@huawei.com>
Date:   Mon, 25 Apr 2022 19:12:30 +0800
From:   Miaohe Lin <linmiaohe@...wei.com>
To:     <akpm@...ux-foundation.org>
CC:     <ying.huang@...el.com>, <iamjoonsoo.kim@....com>, <hch@....de>,
        <osalvador@...e.de>, <linux-mm@...ck.org>,
        <linux-kernel@...r.kernel.org>, <linmiaohe@...wei.com>
Subject: [PATCH v3 4/6] mm/vmscan: take all base pages of THP into account when race with speculative reference

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@...wei.com>
---
 mm/vmscan.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 82e6fa83c472..10ba16fdd748 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1887,7 +1887,7 @@ 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