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Wed, 02 Sep 2026 19:00:24 -0700 (PDT) From: Kunwu Chan X-Google-Original-From: Kunwu Chan To: SJ Park Cc: Kunwu Chan , Andrew Morton , damon@lists.linux.dev, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Kunwu Chan Subject: Re: [PATCH 01/12] mm/damon/core: use damon_nr_samples_per_aggr() for max merge threshold Date: Thu, 3 Sep 2026 10:00:08 +0800 Message-ID: <20260903020012.4160595-1-kunwu.chan@linux.dev> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260902054747.99370-2-sj@kernel.org> References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 55B6FC0004 X-Stat-Signature: gtbby7cygzsjkidkiur351h5n9zbym8m X-HE-Tag: 1788400826-793122 X-HE-Meta: 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 AFFdOZ04 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, 1 Sep 2026 22:47:34 -0700 SJ Park wrote: > kdamond_merge_regions() open-codes max region merge threshold > calculation. What it does is fundamentally the same as > damon_nr_samples_per_aggr() but missing a few corner cases. The > unhandled corner cases should be rare and make only a negligible level > of monitoring results degradation. But having the inconsistency could > increase future maintenance burden. Use the dedicated function. > > Signed-off-by: SJ Park > --- > mm/damon/core.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/mm/damon/core.c b/mm/damon/core.c > index f748acd6bbd5b..846da6df5b552 100644 > --- a/mm/damon/core.c > +++ b/mm/damon/core.c > @@ -3509,8 +3509,7 @@ static void kdamond_merge_regions(struct damon_ctx *c, unsigned int threshold, > unsigned int max_thres; > bool count_age = true; > > - max_thres = c->attrs.aggr_interval / > - (c->attrs.sample_interval ? c->attrs.sample_interval : 1); > + max_thres = damon_nr_samples_per_aggr(&c->attrs); The helper replacement makes sense to me, and it also keeps the corner-case handling centralized. Reviewed-by: Kunwu Chan Thanks, Kunwu > while (true) { > nr_regions = 0; > damon_for_each_target(t, c) { > -- > 2.47.3 > Sent using hkml (https://github.com/sjp38/hackermail)