From nobody Wed Apr 8 09:41:04 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1189DFA373E for ; Wed, 26 Oct 2022 23:00:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233965AbiJZXAD (ORCPT ); Wed, 26 Oct 2022 19:00:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40936 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233946AbiJZW76 (ORCPT ); Wed, 26 Oct 2022 18:59:58 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A3AEA26558 for ; Wed, 26 Oct 2022 15:59:52 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 39CA8B82473 for ; Wed, 26 Oct 2022 22:59:51 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7A973C433B5; Wed, 26 Oct 2022 22:59:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1666825189; bh=PcpzlnNHZWtuE8/7HVnA2SeaMVIQ6XHWVj8vUJ1ZrF4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lRniJU/9ikWpyMRR5kfjgU/6Iqe32PXn0o8jXqKhZolqSUOL6HEenaGW3obcwZEyZ ufRoarBtPKYdazvBBO4J4gqrFYNmg1QOcFolHNHL1vfvd5J/VnXK97cZPvcjJuH9tq 2VQBajLilWdf5g8PTKhxX7S8lRiOGISlVxGh1mrqP/5i/kJEHSfr633CYOYblvKrgu VVFj2q/MDA8hq8R7Ka2PJelPuGw/AwgYXp5YUZ7w5vthBWlPuouiB9i9qYzIrXBGmE NrB2LowcimyC2ELjFifkgsNJbkQgkismBiW85BYvRgRbFWX8ZXxy4om7MQw9nrtNL6 kjwOlB50TEX1Q== From: SeongJae Park To: Andrew Morton Cc: damon@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, SeongJae Park Subject: [PATCH v2 01/12] mm/damon/core: split out DAMOS-charged region skip logic into a new function Date: Wed, 26 Oct 2022 22:59:32 +0000 Message-Id: <20221026225943.100429-2-sj@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20221026225943.100429-1-sj@kernel.org> References: <20221026225943.100429-1-sj@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" The DAMOS action applying function, 'damon_do_apply_schemes()', is quite long and not so simple. Split out the already quota-charged region skip code, which is not a small amount of simple code, into a new function with some comments for better readability. Signed-off-by: SeongJae Park Signed-off-by: Andrew Morton --- mm/damon/core.c | 96 +++++++++++++++++++++++++++++++++---------------- 1 file changed, 65 insertions(+), 31 deletions(-) diff --git a/mm/damon/core.c b/mm/damon/core.c index 36d098d06c55..06b50ede9cc6 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -694,6 +694,67 @@ static bool damos_valid_target(struct damon_ctx *c, st= ruct damon_target *t, return c->ops.get_scheme_score(c, t, r, s) >=3D s->quota.min_score; } =20 +/* + * damos_skip_charged_region() - Check if the given region or starting par= t of + * it is already charged for the DAMOS quota. + * @t: The target of the region. + * @rp: The pointer to the region. + * @s: The scheme to be applied. + * + * If a quota of a scheme has exceeded in a quota charge window, the schem= e's + * action would applied to only a part of the target access pattern fulfil= ling + * regions. To avoid applying the scheme action to only already applied + * regions, DAMON skips applying the scheme action to the regions that cha= rged + * in the previous charge window. + * + * This function checks if a given region should be skipped or not for the + * reason. If only the starting part of the region has previously charged, + * this function splits the region into two so that the second one covers = the + * area that not charged in the previous charge widnow and saves the second + * region in *rp and returns false, so that the caller can apply DAMON act= ion + * to the second one. + * + * Return: true if the region should be entirely skipped, false otherwise. + */ +static bool damos_skip_charged_region(struct damon_target *t, + struct damon_region **rp, struct damos *s) +{ + struct damon_region *r =3D *rp; + struct damos_quota *quota =3D &s->quota; + unsigned long sz_to_skip; + + /* Skip previously charged regions */ + if (quota->charge_target_from) { + if (t !=3D quota->charge_target_from) + return true; + if (r =3D=3D damon_last_region(t)) { + quota->charge_target_from =3D NULL; + quota->charge_addr_from =3D 0; + return true; + } + if (quota->charge_addr_from && + r->ar.end <=3D quota->charge_addr_from) + return true; + + if (quota->charge_addr_from && r->ar.start < + quota->charge_addr_from) { + sz_to_skip =3D ALIGN_DOWN(quota->charge_addr_from - + r->ar.start, DAMON_MIN_REGION); + if (!sz_to_skip) { + if (damon_sz_region(r) <=3D DAMON_MIN_REGION) + return true; + sz_to_skip =3D DAMON_MIN_REGION; + } + damon_split_region_at(t, r, sz_to_skip); + r =3D damon_next_region(r); + *rp =3D r; + } + quota->charge_target_from =3D NULL; + quota->charge_addr_from =3D 0; + } + return false; +} + static void damon_do_apply_schemes(struct damon_ctx *c, struct damon_target *t, struct damon_region *r) @@ -702,7 +763,7 @@ static void damon_do_apply_schemes(struct damon_ctx *c, =20 damon_for_each_scheme(s, c) { struct damos_quota *quota =3D &s->quota; - unsigned long sz =3D damon_sz_region(r); + unsigned long sz; struct timespec64 begin, end; unsigned long sz_applied =3D 0; =20 @@ -713,41 +774,14 @@ static void damon_do_apply_schemes(struct damon_ctx *= c, if (quota->esz && quota->charged_sz >=3D quota->esz) continue; =20 - /* Skip previously charged regions */ - if (quota->charge_target_from) { - if (t !=3D quota->charge_target_from) - continue; - if (r =3D=3D damon_last_region(t)) { - quota->charge_target_from =3D NULL; - quota->charge_addr_from =3D 0; - continue; - } - if (quota->charge_addr_from && - r->ar.end <=3D quota->charge_addr_from) - continue; - - if (quota->charge_addr_from && r->ar.start < - quota->charge_addr_from) { - sz =3D ALIGN_DOWN(quota->charge_addr_from - - r->ar.start, DAMON_MIN_REGION); - if (!sz) { - if (damon_sz_region(r) <=3D - DAMON_MIN_REGION) - continue; - sz =3D DAMON_MIN_REGION; - } - damon_split_region_at(t, r, sz); - r =3D damon_next_region(r); - sz =3D damon_sz_region(r); - } - quota->charge_target_from =3D NULL; - quota->charge_addr_from =3D 0; - } + if (damos_skip_charged_region(t, &r, s)) + continue; =20 if (!damos_valid_target(c, t, r, s)) continue; =20 /* Apply the scheme */ + sz =3D damon_sz_region(r); if (c->ops.apply_scheme) { if (quota->esz && quota->charged_sz + sz > quota->esz) { --=20 2.25.1