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From:   Hyeongtak Ji <hyeongtak.ji@gmail.com>
To:     sj@kernel.org, akpm@linux-foundation.org
Cc:     damon@lists.linux.dev, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org,
        Hyeongtak Ji <hyeongtak.ji@gmail.com>,
        Hyeongtak Ji <hyeongtak.ji@sk.com>
Subject: [PATCH] mm/damon: Prevent unnecessary age reset for regions
Date:   Mon,  7 Aug 2023 18:44:35 +0900
Message-Id: <1691401475-3796-1-git-send-email-hyeongtak.ji@gmail.com>
Precedence: bulk

DAMON resets the age of each region after applying each scheme,
regardless of whether the scheme has been successfully applied.

This patch adds a simple condition to prevent the age of regions from
being reset when schemes have not been actually applied.

Signed-off-by: Hyeongtak Ji <hyeongtak.ji@sk.com>
---
 mm/damon/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/damon/core.c b/mm/damon/core.c
index 91cff7f2997e..4044fcf18ac1 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -908,7 +908,7 @@ static void damos_apply_scheme(struct damon_ctx *c, struct damon_target *t,
 			quota->charge_addr_from = r->ar.end + 1;
 		}
 	}
-	if (s->action != DAMOS_STAT)
+	if (s->action != DAMOS_STAT && sz_applied > 0)
 		r->age = 0;
 
 update_stat:
-- 
2.7.4