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From:   SeongJae Park <sj@kernel.org>
Cc:     SeongJae Park <sj@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        damon@lists.linux.dev, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
Subject: [RFC 7/8] mm/damon/core: skip updating nr_accesses_bp for each aggregation interval
Date:   Sat,  9 Sep 2023 03:37:10 +0000
Message-Id: <20230909033711.55794-8-sj@kernel.org>
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damon_merge_regions_of(), which is called for each aggregation interval,
updates nr_accesses_bp to nr_accesses * 10000.  However, nr_accesses_bp
is updated for each sampling interval via damon_moving_sum() using the
aggregation interval as the moving time window.  And by the definition
of the algorithm, the value becomes same to discrete-window based sum
for each time window-aligned time.  Hence, nr_accesses_bp will be same
to nr_accesses * 10000 for each aggregation interval without explicit
update.  Remove the unnecessary update of nr_accesses_bp in
damon_merge_regions_of().

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/core.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/mm/damon/core.c b/mm/damon/core.c
index c813407c09b4..1ba7c4669263 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -1182,8 +1182,6 @@ static void damon_merge_regions_of(struct damon_target *t, unsigned int thres,
 		else
 			r->age++;
 
-		r->nr_accesses_bp = r->nr_accesses * 10000;
-
 		if (prev && prev->ar.end == r->ar.start &&
 		    abs(prev->nr_accesses - r->nr_accesses) <= thres &&
 		    damon_sz_region(prev) + damon_sz_region(r) <= sz_limit)
-- 
2.25.1