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 2DF7C47D94F for ; Tue, 1 Sep 2026 13:28:24 +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=1788269306; cv=none; b=HSQQruBxqVodbg0uaJdtLDLqfKk0j+iGuCjK3Comyev2pVc9W6cZSWG47iyf+beidgE3ZKWRQKEcE9+R/NuSK8iLINzt76Bm2l1B+sVWtKGcdMRzJryDS28UJqvYQq27B+Qx0Lyvoafsc/G4p0LRBnxQajupeGLgDCVYlDhV3lc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788269306; c=relaxed/simple; bh=S4uadd1M7OyW4vkdJ4vOf857Q2HAYPa9KGRvomykniQ=; h=From:Subject:To:Cc:In-Reply-To:References:Content-Type:Date: Message-Id; b=Spzhx9YjaQR/4kz/8OyqlFqa0zZgQmLfuYgkpnF3PcFAtqs0posMkeqYmHDH4hYHGT0ymlBjSq3fFJvLLSdsXBppHk011y5xPNezBKniycw3y1xJCAuCfXtmrM66fCo9mOit1tCAia1x8N5AqZmlAtRxF1txYmxqiHXrxbuoU58= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Iu7F5pDP; 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="Iu7F5pDP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A11051F000E9; Tue, 1 Sep 2026 13:28:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788269304; bh=ZJGNO/FVaxR04sgcYa7TiM/XLsznAO8u/PXR7zjgKV4=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=Iu7F5pDPGkuMfSg8Qvks2+LSEMB3gszogyHEBZAiQ5Nhmk6ir9EK2iC1E2gbPVhVh GhYFZ+3HK0zxH4Y8AvSioLIG+1i39cAlCV1ypV9GljbYA4SBgxllnAtGyADy0oVeZ2 LrATv5y9nUtZ/5g53oeXCYgg9vsLD6dAZyB6I/ve/Ttl9wedj41OcSH7rYHZ369RI4 dYwTrzjebHj87A65wLAf79kc4OfHFxhcPP+FZXy9K6oL+DNyVpCGQ5UML8fxJZW2xn xUHOoWRuhWzT9HFL2VLxxf5Q2+F/x8p1HStpBZT8ToLk9b3zXSraARH/1ODqdVp4qp X1sOpfIZQFJ4g== From: sashiko-bot@kernel.org Subject: Re: [PATCH 1/8] mm/damon/core: skip applying scheme if region split for quota fails Reply-To: sashiko-reviews@lists.linux.dev To: "SJ Park" Cc: damon@lists.linux.dev In-Reply-To: <20260901131850.98037-2-sj@kernel.org> References: <20260901131850.98037-1-sj@kernel.org> <20260901131850.98037-2-sj@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Tue, 01 Sep 2026 13:28:24 +0000 Message-Id: <20260901132824.A11051F000E9@smtp.kernel.org> Precedence: bulk X-Mailing-List: damon@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: > damos_apply_scheme() splits a region and apply the action to the > subregion if it is needed for not violating the quota. The split > operation (damon_split_region_at()) could fail for allocation failure. > In the case, the quota could be violated. From the user's perspective, > DAMOS becomes more aggressive than expected under the extreme situation. > Handle the failure. >=20 > The user impact is not critical. The failure of damon_split_region_at() > is unlikely since it is arguably too small to fail. Also DAMOS being > aggressive is limited to the single region. Users can set > min_nr_regions to set the maximum size of each region. If it is > reasonably set, the transient overhead shouldn't be critical. >=20 > The issue was discovered [1] by Sashiko. >=20 > [1] https://lore.kernel.org/20260718171523.87547-1-sj@kernel.org >=20 > Fixes: 2b8a248d5873 ("mm/damon/schemes: implement size quota for schemes = application speed control") > Cc: # 5.16.x > 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/20260901131850.9803= 7-1-sj@kernel.org?part=3D1