From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 64BCE2459E1; Sun, 21 Jun 2026 15:57:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782057462; cv=none; b=B/7m8wanf1gotIZ5yRRkwLujZl5bybJZ5XqzLxuZEkZw7RV0XH1jggr+mb2BLV+45V5w1rFAAsc230kvGa7mmQ+g7JIqTr3+MMKmtUTw2ofYF4OtPRkScD/6mTBFgMiH88434irMBmdt9L0YCeOU7rvI/mam1K4oaeZueL13PGg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782057462; c=relaxed/simple; bh=zJqm1adsIS5HEif7Eb/DN7AiXXEatUoLj8AlNis5xDs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=iRktdQNPAp2jff41L73N7Zzq4VLfmbWnCWGV3LDQyRWcxhq8j8JIdAMlNtdc8HWYWrrIjLR0MBqJBd5P6hfc2Oz9wVT2Ff+ushT3jxBhH79rDt2twi246nyB8Qh9zik0hyvRbMIVbndGFf4y3xl+Q9PoHJjLdz5PFPc42PSanyc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Bic3bOc+; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Bic3bOc+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B85BD1F000E9; Sun, 21 Jun 2026 15:57:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1782057460; bh=pZ+M6B9rIjrwF8KBw1ippRvOtN9mQ1VfyOBQJ+Ky9uI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Bic3bOc+7MqO9Am0FvLYr3v1YRndBTbKdZxnFGv0alNSNreSH/E8jC5eKlnQYEPL1 XW6FGiwkz5D4WJXFtyfzGYhfT8anUc4/SNmvmuSvK5X01tzNv5pcx7WSYx++9w6Buv 3McFZ/ZcMddHweS0ulqgNa4lNlCuWDWlxxfBMupSaIIkKXHPqzn/tCxqoD2TfM5B4q +CwQ8iNOvOuf+r14D3Ia2Yl7yTX+el2HWA+Gi82lILt87OCsF3Wmm6zgsdbDBPaNA1 yO77s6MchmATVf7Ck+1PG6SwP/Kc4Zji86BVT7yGpkGQE2PYotbqgK1ikTHALOTOH9 nHSZcfBprXaug== From: SeongJae Park To: Cc: SeongJae Park , Andrew Morton , damon@lists.linux.dev, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [RFC PATCH v1.2 12/17] mm/damon/core: remove nr_accesses_bp setups and updates Date: Sun, 21 Jun 2026 08:57:08 -0700 Message-ID: <20260621155715.87932-13-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260621155715.87932-1-sj@kernel.org> References: <20260621155715.87932-1-sj@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit DAMON core sets and updates nr_accesses_bp in multiple places. It explains how delicate it is. The field is no more being used for any real purpose, and replaced by a simpler function. Remove the setups and updates. Signed-off-by: SeongJae Park --- mm/damon/core.c | 22 ++-------------------- 1 file changed, 2 insertions(+), 20 deletions(-) diff --git a/mm/damon/core.c b/mm/damon/core.c index 76ac58bf3dff9..c3c8e83234011 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -301,7 +301,6 @@ struct damon_region *damon_new_region(unsigned long start, unsigned long end) region->ar.start = start; region->ar.end = end; region->nr_accesses = 0; - region->nr_accesses_bp = 0; for (i = 0; i < DAMON_MAX_PROBES; i++) region->probe_hits[i] = 0; INIT_LIST_HEAD(®ion->list); @@ -875,20 +874,17 @@ static void damon_update_monitoring_result(struct damon_region *r, { r->last_nr_accesses = damon_nr_accesses_for_new_attrs( r->last_nr_accesses, old_attrs, new_attrs); - if (!aggregating) { + if (!aggregating) r->nr_accesses = damon_nr_accesses_for_new_attrs( r->nr_accesses, old_attrs, new_attrs); - r->nr_accesses_bp = r->nr_accesses * 10000; - } else { + else /* * if this is called in the middle of the aggregation, reset * the aggregations we made so far for this aggregation * interval. In other words, make the status like * kdamond_reset_aggregated() is called. */ - r->nr_accesses_bp = r->last_nr_accesses * 10000; r->nr_accesses = 0; - } r->age = damon_age_for_new_attrs(r->age, old_attrs, new_attrs); } @@ -3103,7 +3099,6 @@ static void damon_merge_two_regions(struct damon_target *t, l->nr_accesses = (l->nr_accesses * sz_l + r->nr_accesses * sz_r) / (sz_l + sz_r); - l->nr_accesses_bp = l->nr_accesses * 10000; l->age = (l->age * sz_l + r->age * sz_r) / (sz_l + sz_r); l->ar.end = r->ar.end; /* todo: do this for only installed probes */ @@ -3215,7 +3210,6 @@ static void damon_split_region_at(struct damon_target *t, new->age = r->age; new->last_nr_accesses = r->last_nr_accesses; - new->nr_accesses_bp = r->nr_accesses_bp; new->nr_accesses = r->nr_accesses; /* todo: do this for only installed probes */ memcpy(new->probe_hits, r->probe_hits, sizeof(r->probe_hits)); @@ -3784,18 +3778,6 @@ static unsigned int damon_moving_sum(unsigned int mvsum, unsigned int nomvsum, void damon_update_region_access_rate(struct damon_region *r, bool accessed, struct damon_attrs *attrs) { - unsigned int len_window = 1; - - /* - * sample_interval can be zero, but cannot be larger than - * aggr_interval, owing to validation of damon_set_attrs(). - */ - if (attrs->sample_interval) - len_window = damon_max_nr_accesses(attrs); - r->nr_accesses_bp = damon_moving_sum(r->nr_accesses_bp, - r->last_nr_accesses * 10000, len_window, - accessed ? 10000 : 0); - if (accessed) r->nr_accesses++; } -- 2.47.3