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 A113735C6AB for ; Wed, 9 Sep 2026 05:35:00 +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=1788932101; cv=none; b=mKA0v0Tp8cBwf7FLqSAOXjv+Fdn7IoYrol/1VBgbqD4hLS/GoEbsc+fJbC435RUUrIU9md8a5weBMgLXmtnOv+y2cnJ6oGMHXqwts+snBLKtnzNnFpI+t0AVulfPkXZRET8TYLjrA6srdfViTycfcOj/QR5xlAc8Ce+ZM8jHsHI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788932101; c=relaxed/simple; bh=KK/KiZ6/G50wRTrV8CdRcUB3Zi8s04zrzuQ8Xm37WnU=; h=From:Subject:To:Cc:In-Reply-To:References:Content-Type:Date: Message-Id; b=PTwA3vhCIP+jxwzO3abtCbwqzRn4MaaA3/uYksvN0BBdTMQq1P5ZDPVPVEDlhHF7nSO509YPU6oyF827GIcvaA1JwzZ/dhqqfnkCPCSsTylREO9TSkCjyeXrdDDALHVmUimBy/YMU8aOBviI1a+iAiOOJ+qlSjocGsNRQeJ0VzU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=J4D7PCZq; 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="J4D7PCZq" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 38D211F00A3D; Wed, 9 Sep 2026 05:35:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788932100; bh=r3um1ByCId5C5HLhCzFDaGvR1AKDgYsTbmo8z9lxuus=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=J4D7PCZq6tIakNRTHSYwngZX02Sa4a/hX3e3LEhE0M8kfTHatQ6HMGzCKRZs0CxPE xlEiLJLSEigOhsO3aqeSMb1uXQKez0RLSf4wj6VNB4gDBUBSvpIzn/poIKBZGINWLN 054jJxs92yNvUK2QkBDixIQz4/yqX9QQtM+xHC8O6yfdc1oeQHrfbg4dMRlLosnSGQ /tzP4dK3wLcuLX6BuXQV2KOogWQPzutZk03x4YlYwX2MSpJHfwu/rU2By9sabitj05 NWGHVv/JLL0UBkTWAdS0I7bS5AvLSuAcFmKwL0K/0jBAKsbp+1reEUIY7DQGZzDz8h znG7jCpZftHfQ== From: sashiko-bot@kernel.org Subject: Re: [PATCH 7.2.y] mm/damon/paddr: drop last same folio access check reuse optimization Reply-To: sashiko-reviews@lists.linux.dev To: "SJ Park" Cc: damon@lists.linux.dev In-Reply-To: <20260909053151.242944-1-sj@kernel.org> References: <2026090851-hulk-tutor-8154@gregkh> <20260909053151.242944-1-sj@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Wed, 09 Sep 2026 05:34:59 +0000 Message-Id: <20260909053500.38D211F00A3D@smtp.kernel.org> Precedence: bulk X-Mailing-List: damon@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: > It can race when multiple kdamonds are being used. The problem from the > race is doubtful, but the gain from the optimization is also doubtful. > Simply drop the optimization in favor of code simplicity. >=20 > The user impact is doubtfully trivial. After all, this kind of > interference can happen only by intentional user setup. Even if it > happens, it will be rare, and the consequence is degradation of the > best-effort monitoring results. No critical consequences like kernel > panic or memory corruption happen. >=20 > The race was discovered [1] by Sashiko. >=20 > Link: https://lore.kernel.org/20260715031002.108504-5-sj@kernel.org > Link: https://lore.kernel.org/20260621204050.10993-1-sj@kernel.org [1] > Fixes: a28397beb55b ("mm/damon: implement primitives for physical address= space monitoring") > Signed-off-by: SJ Park > Cc: # 5.16.x > Signed-off-by: Andrew Morton > (cherry picked from commit f23f0aa62b2f32c2b12f95959fc4603ef81678b2) > Signed-off-by: SJ Park Sashiko has reviewed this patch and found no issues. It looks great! --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20260909053151.2429= 44-1-sj@kernel.org?part=3D1