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Wed, 06 Aug 2025 09:43:29 -0700 (PDT) Received: from bijan-laptop.attlocal.net ([2600:1700:680e:c000:f6a5:255b:e469:fba9]) by smtp.gmail.com with ESMTPSA id 3f1490d57ef6-e8fd3713e9fsm5596151276.5.2025.08.06.09.43.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 06 Aug 2025 09:43:28 -0700 (PDT) From: Bijan Tabatabai To: damon@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: sj@kernel.org, Andrew Morton , Bijan Tabatabai , Bijan Tabatabai Subject: [PATCH] mm/damon/core: skip needless update of next_{aggregation,ops_update}_sis Date: Wed, 6 Aug 2025 11:43:16 -0500 Message-ID: <20250806164316.5728-1-bijan311@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Bijan Tabatabai In damon_set_attrs(), ctx->next_{aggregation,ops_update}_sis would be reset, even if the sample interval, aggregation interval, or ops update interval were not changed. If damon_set_attrs() is called relatively frequently, such as by frequent "commit" operations, aggregation and ops update operations could be needlessly delayed. This patch avoids this by only updating next_{aggregation,ops_update}_sis if the relevant intervals were changed. Cc: Bijan Tabatabai Signed-off-by: Bijan Tabatabai --- This patch came from discussions in [1]. [1] https://lore.kernel.org/all/20250805162022.4920-1-bijan311@gmail.com/ --- mm/damon/core.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) diff --git a/mm/damon/core.c b/mm/damon/core.c index 6a2fe1f2c952..1c3d8b92257c 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -693,6 +693,12 @@ int damon_set_attrs(struct damon_ctx *ctx, struct damo= n_attrs *attrs) unsigned long sample_interval =3D attrs->sample_interval ? attrs->sample_interval : 1; struct damos *s; + bool sample_interval_changed =3D ctx->attrs.sample_interval !=3D + attrs->sample_interval; + bool aggr_interval_changed =3D ctx->attrs.aggr_interval !=3D + attrs->aggr_interval; + bool ops_update_interval_changed =3D ctx->attrs.ops_update_interval !=3D + attrs->ops_update_interval; bool aggregating =3D ctx->passed_sample_intervals < ctx->next_aggregation_sis; =20 @@ -710,10 +716,12 @@ int damon_set_attrs(struct damon_ctx *ctx, struct dam= on_attrs *attrs) if (!attrs->aggr_samples) attrs->aggr_samples =3D attrs->aggr_interval / sample_interval; =20 - ctx->next_aggregation_sis =3D ctx->passed_sample_intervals + - attrs->aggr_interval / sample_interval; - ctx->next_ops_update_sis =3D ctx->passed_sample_intervals + - attrs->ops_update_interval / sample_interval; + if (sample_interval_changed || aggr_interval_changed) + ctx->next_aggregation_sis =3D ctx->passed_sample_intervals + + attrs->aggr_interval / sample_interval; + if (sample_interval_changed || ops_update_interval_changed) + ctx->next_ops_update_sis =3D ctx->passed_sample_intervals + + attrs->ops_update_interval / sample_interval; =20 damon_update_monitoring_results(ctx, attrs, aggregating); ctx->attrs =3D *attrs; --=20 2.43.0