From: SJ Park <sj@kernel.org>
Cc: SJ Park <sj@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
damon@lists.linux.dev, linux-kernel@vger.kernel.org,
linux-mm@kvack.org
Subject: [RFC PATCH 3/6] mm/damon/core: s/nr_accesses_to_accesses_bp/sample_count_to_bp/
Date: Mon, 6 Jul 2026 21:38:23 -0700 [thread overview]
Message-ID: <20260707043828.97900-4-sj@kernel.org> (raw)
In-Reply-To: <20260707043828.97900-1-sj@kernel.org>
damon_nr_accesses_to_accesses_bp() actually converts a positive sample
count to the ratio. Rename it to better describe what it really does
and not confusing for more general uses.
Also remove the obsolete comment about division-by-zero. Commit
35d4a3cf70a8 ("mm/damon/ops-common: handle extreme intervals in
damon_hot_score()") modified damon_nr_samples_per_aggr() to always
return non-zero. Hence no division-by-zero of the note can happen.
Signed-off-by: SJ Park <sj@kernel.org>
---
mm/damon/core.c | 17 +++++------------
mm/damon/tests/core-kunit.h | 8 ++++----
2 files changed, 9 insertions(+), 16 deletions(-)
diff --git a/mm/damon/core.c b/mm/damon/core.c
index ca530faaa4f83..718268df27fa7 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -883,25 +883,18 @@ static unsigned int damon_sample_bp_to_count(
return bp * damon_nr_samples_per_aggr(attrs) / 10000;
}
-/*
- * Convert nr_accesses to access ratio in bp (per 10,000).
- *
- * Callers should ensure attrs.aggr_interval is not zero, like
- * damon_update_monitoring_results() does . Otherwise, divide-by-zero would
- * happen.
- */
-static unsigned int damon_nr_accesses_to_accesses_bp(
- unsigned int nr_accesses, struct damon_attrs *attrs)
+/* convert sample count to ratio in bp (per 10,000) */
+static unsigned int damon_sample_count_to_bp(
+ unsigned int count, struct damon_attrs *attrs)
{
- return mult_frac(nr_accesses, 10000, damon_nr_samples_per_aggr(attrs));
+ return mult_frac(count, 10000, damon_nr_samples_per_aggr(attrs));
}
static unsigned int damon_nr_accesses_for_new_attrs(unsigned int nr_accesses,
struct damon_attrs *old_attrs, struct damon_attrs *new_attrs)
{
return damon_sample_bp_to_count(
- damon_nr_accesses_to_accesses_bp(
- nr_accesses, old_attrs),
+ damon_sample_count_to_bp(nr_accesses, old_attrs),
new_attrs);
}
diff --git a/mm/damon/tests/core-kunit.h b/mm/damon/tests/core-kunit.h
index 0124f83b39b83..86eae3a590354 100644
--- a/mm/damon/tests/core-kunit.h
+++ b/mm/damon/tests/core-kunit.h
@@ -575,7 +575,7 @@ static void damon_test_set_regions(struct kunit *test)
}, 3);
}
-static void damon_test_nr_accesses_to_accesses_bp(struct kunit *test)
+static void damon_test_sample_count_to_bp(struct kunit *test)
{
struct damon_attrs attrs = {
.sample_interval = 10,
@@ -585,7 +585,7 @@ static void damon_test_nr_accesses_to_accesses_bp(struct kunit *test)
/*
* In some cases such as 32bit architectures where UINT_MAX is
* ULONG_MAX, attrs.aggr_interval becomes zero. Calling
- * damon_nr_accesses_to_accesses_bp() in the case will cause
+ * damon_sample_count_to_bp() in the case will cause
* divide-by-zero. Such case is prohibited in normal execution since
* the caution is documented on the comment for the function, and
* damon_update_monitoring_results() does the check. Skip the test in
@@ -594,7 +594,7 @@ static void damon_test_nr_accesses_to_accesses_bp(struct kunit *test)
if (!attrs.aggr_interval)
kunit_skip(test, "aggr_interval is zero.");
- KUNIT_EXPECT_EQ(test, damon_nr_accesses_to_accesses_bp(123, &attrs), 0);
+ KUNIT_EXPECT_EQ(test, damon_sample_count_to_bp(123, &attrs), 0);
}
static void damon_test_update_monitoring_result(struct kunit *test)
@@ -1572,7 +1572,7 @@ static struct kunit_case damon_test_cases[] = {
KUNIT_CASE(damon_test_split_above_half_progresses),
KUNIT_CASE(damon_test_ops_registration),
KUNIT_CASE(damon_test_set_regions),
- KUNIT_CASE(damon_test_nr_accesses_to_accesses_bp),
+ KUNIT_CASE(damon_test_sample_count_to_bp),
KUNIT_CASE(damon_test_update_monitoring_result),
KUNIT_CASE(damon_test_set_attrs),
KUNIT_CASE(damon_test_mvsum),
--
2.47.3
next prev parent reply other threads:[~2026-07-07 4:39 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-07 4:38 [RFC PATCH 0/6] mm/damon: update probe hits for runtime parameter commits SJ Park
2026-07-07 4:38 ` [RFC PATCH 1/6] mm/damon/core: s/damon_max_nr_accesses()/damon_nr_samples_per_aggr()/ SJ Park
2026-07-07 4:38 ` [RFC PATCH 2/6] mm/damon/core: s/accesses_bp_to_nr_accesses/sample_bp_to_count/ SJ Park
2026-07-07 4:38 ` SJ Park [this message]
2026-07-07 4:38 ` [RFC PATCH 4/6] mm/damon/core: s/nr_accesses_for_new_attrs/nr_samples_for_new_attrs/ SJ Park
2026-07-07 4:38 ` [RFC PATCH 5/6] mm/damon/core: update probe hits for new parameter commit SJ Park
2026-07-07 4:38 ` [RFC PATCH 6/6] mm/damon/core: handle unreset probe_hits in probe_hits_mvsum() SJ Park
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20260707043828.97900-4-sj@kernel.org \
--to=sj@kernel.org \
--cc=akpm@linux-foundation.org \
--cc=damon@lists.linux.dev \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox