linux-kernel - [PATCH RFC] mm/swap: make release_pages() and put

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Message-Id: <20190524193415.9733-1-ira.weiny@intel.com>
Date:   Fri, 24 May 2019 12:34:15 -0700
From:   ira.weiny@...el.com
To:     Andrew Morton <akpm@...ux-foundation.org>,
        Vlastimil Babka <vbabka@...e.cz>,
        Michal Hocko <mhocko@...e.com>,
        Matthew Wilcox <willy@...radead.org>
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        Ira Weiny <ira.weiny@...el.com>
Subject: [PATCH RFC] mm/swap: make release_pages() and put_pages() match

From: Ira Weiny <ira.weiny@...el.com>

RFC I have no idea if this is correct or not.  But looking at
release_pages() I see a call to both __ClearPageActive() and
__ClearPageWaiters() while in __page_cache_release() I do not.

Is this a bug which needs to be fixed?  Did I miss clearing active
somewhere else in the call chain of put_page?

This was found via code inspection while determining if release_pages()
and the new put_user_pages() could be interchangeable.

Signed-off-by: Ira Weiny <ira.weiny@...el.com>
---
 mm/swap.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/mm/swap.c b/mm/swap.c
index 3a75722e68a9..9d0432baddb0 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -69,6 +69,7 @@ static void __page_cache_release(struct page *page)
 		del_page_from_lru_list(page, lruvec, page_off_lru(page));
 		spin_unlock_irqrestore(&pgdat->lru_lock, flags);
 	}
+	__ClearPageActive(page);
 	__ClearPageWaiters(page);
 	mem_cgroup_uncharge(page);
 }
-- 
2.20.1