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Date:   Tue, 26 Jan 2021 22:01:11 +0000
From:   Matthew Wilcox <willy@infradead.org>
To:     Yu Zhao <yuzhao@google.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Hugh Dickins <hughd@google.com>,
        Alex Shi <alex.shi@linux.alibaba.com>,
        Michal Hocko <mhocko@kernel.org>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Vladimir Davydov <vdavydov.dev@gmail.com>,
        Roman Gushchin <guro@fb.com>, Vlastimil Babka <vbabka@suse.cz>,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 03/10] mm: don't pass "enum lru_list" to lru list
 addition functions
Message-ID: <20210126220111.GO308988@casper.infradead.org>
References: <20210122220600.906146-1-yuzhao@google.com>
 <20210122220600.906146-4-yuzhao@google.com>
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On Fri, Jan 22, 2021 at 03:05:53PM -0700, Yu Zhao wrote:
> +++ b/mm/swap.c
> @@ -231,7 +231,7 @@ static void pagevec_move_tail_fn(struct page *page, struct lruvec *lruvec)
>  	if (!PageUnevictable(page)) {
>  		del_page_from_lru_list(page, lruvec, page_lru(page));
>  		ClearPageActive(page);
> -		add_page_to_lru_list_tail(page, lruvec, page_lru(page));
> +		add_page_to_lru_list_tail(page, lruvec);
>  		__count_vm_events(PGROTATED, thp_nr_pages(page));
>  	}

Is it profitable to do ...

-		del_page_from_lru_list(page, lruvec, page_lru(page));
+		enum lru_list lru = page_lru(page);
+		del_page_from_lru_list(page, lruvec, lru);
		ClearPageActive(page);
-		add_page_to_lru_list_tail(page, lruvec, page_lru(page));
+		lru &= ~LRU_ACTIVE;
+		add_page_to_lru_list_tail(page, lruvec, lru);