linux-kernel - [PATCH 1/9] mm/damon/core: make DAMOS uses nr_accesses_bp instead of nr

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Message-Id: <20230916020945.47296-2-sj@kernel.org>
Date:   Sat, 16 Sep 2023 02:09:37 +0000
From:   SeongJae Park <sj@...nel.org>
To:     Andrew Morton <akpm@...ux-foundation.org>
Cc:     SeongJae Park <sj@...nel.org>, damon@...ts.linux.dev,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: [PATCH 1/9] mm/damon/core: make DAMOS uses nr_accesses_bp instead of nr_accesses

DAMON provides nr_accesses_bp, which becomes same to nr_accesses * 10000
for every aggregation interval, but updated every sampling interval with
a reasonable accuracy.  Since DAMON-based operation schemes are applied
in every aggregation interval using nr_accesses, using nr_accesses_bp
instead will make no difference to users.  Meanwhile, it allows DAMOS to
apply the schemes in a time interval that less than the aggregation
interval.  It could be useful and more flexible for some cases.  Do it.

Signed-off-by: SeongJae Park <sj@...nel.org>
---
 mm/damon/core.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/mm/damon/core.c b/mm/damon/core.c
index b15cf47d2d29..79fef5145a4b 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -770,12 +770,13 @@ static void damon_split_region_at(struct damon_target *t,
 static bool __damos_valid_target(struct damon_region *r, struct damos *s)
 {
 	unsigned long sz;
+	unsigned int nr_accesses = r->nr_accesses_bp / 10000;
 
 	sz = damon_sz_region(r);
 	return s->pattern.min_sz_region <= sz &&
 		sz <= s->pattern.max_sz_region &&
-		s->pattern.min_nr_accesses <= r->nr_accesses &&
-		r->nr_accesses <= s->pattern.max_nr_accesses &&
+		s->pattern.min_nr_accesses <= nr_accesses &&
+		nr_accesses <= s->pattern.max_nr_accesses &&
 		s->pattern.min_age_region <= r->age &&
 		r->age <= s->pattern.max_age_region;
 }
-- 
2.25.1