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From:   js1304@gmail.com
To:     Andrew Morton <akpm@linux-foundation.org>
Cc:     linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        Johannes Weiner <hannes@cmpxchg.org>,
        Michal Hocko <mhocko@kernel.org>,
        Hugh Dickins <hughd@google.com>,
        Minchan Kim <minchan@kernel.org>,
        Vlastimil Babka <vbabka@suse.cz>,
        Mel Gorman <mgorman@techsingularity.net>, kernel-team@lge.com,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>
Subject: [PATCH v6 1/6] mm/vmscan: make active/inactive ratio as 1:1 for anon lru
Date:   Wed, 17 Jun 2020 14:26:18 +0900
Message-Id: <1592371583-30672-2-git-send-email-iamjoonsoo.kim@lge.com>
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From: Joonsoo Kim <iamjoonsoo.kim@lge.com>

Current implementation of LRU management for anonymous page has some
problems. Most important one is that it doesn't protect the workingset,
that is, pages on the active LRU list. Although, this problem will be
fixed in the following patchset, the preparation is required and
this patch does it.

What following patchset does is to restore workingset protection. In this
case, newly created or swap-in pages are started their lifetime on the
inactive list. If inactive list is too small, there is not enough chance
to be referenced and the page cannot become the workingset.

In order to provide enough chance to the newly anonymous pages, this patch
makes active/inactive LRU ratio as 1:1.

Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
---
 mm/vmscan.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 749d239..9f940c4 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2212,7 +2212,7 @@ static bool inactive_is_low(struct lruvec *lruvec, enum lru_list inactive_lru)
 	active = lruvec_page_state(lruvec, NR_LRU_BASE + active_lru);
 
 	gb = (inactive + active) >> (30 - PAGE_SHIFT);
-	if (gb)
+	if (gb && is_file_lru(inactive_lru))
 		inactive_ratio = int_sqrt(10 * gb);
 	else
 		inactive_ratio = 1;
-- 
2.7.4