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 4F9F6488218 for ; Mon, 31 Aug 2026 17:45:24 +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=1788198326; cv=none; b=nSg3yn+VAXIzBsPRRpzdNeYcRNuxhoaVzX51IFqJktSZ9sAGoQMw1odWGmt3AYBDFCL7eXhw8DFvOhCY+NZBMAz4EA8XHl9NHzEum532mVWrzaaELx0yAgYq9gJZ11vW91I38hF7sL8Qpo9tLKxhtTvoz4mpUjPLN4/3zERYdLQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788198326; c=relaxed/simple; bh=5gd83QLD5YEcuKU8n+QXI3Qix4rqPSW59i2GlzFRNW0=; h=From:Subject:To:Cc:In-Reply-To:References:Content-Type:Date: Message-Id; b=uhYGQlvjymgVu02mmtGhYgVFpRAaPFgQIHUeufExEoiGmEt5J9s9DIjQah/7ZzaAc2yNJq26NMRz0cfUJxYLHIaTjQ6X65+vMWLleGU0Cfr4yutZgPgWHGoOvAA3GNC6mtXwbe9TTHFOAc6wsl/zT/MGyN+fKr2bWFlQwoqcRPg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=S2H0KMum; 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="S2H0KMum" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 53C7A1F000E9; Mon, 31 Aug 2026 17:45:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788198324; bh=bhLqmKgIDP6q9Yyv0PbdZsBD+tihQ2VoBjSaYTmIIOQ=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=S2H0KMum3m+TxPMNl5IXh6HZH3IpdrF19WAmOm7rB6w5QMFaVnbYg2QQSIktc3dqx VPa6Jg1Jy9gRz80xOrbAz2PgSv6SGEiXD9GtKR+ffkcB1MAHL7yd/+gSmykiOdpL4o zoZ9uGkNSlZnJI+3qIxoG8B8XumrEN1lWClHTj6erl8bL19WZyugWMYiI1gAFd/Ly8 Y2xNKO2HlPhs9Zl0iN8eGG7PRVEjJJG/5wiBFhvBfiKZ8IHovRtObYo7uiYcivPfMK 842ZkUHQCa9P5qwUR7ewnmO5yDIWtYKxVT2jzWI4JIHbikJ+pXqu1jhlmjyuEyF8Xz B/nnTP3QPfNkw== From: sashiko-bot@kernel.org Subject: Re: [RFC PATCH v1.2 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: <20260831140254.72004-2-sj@kernel.org> References: <20260831140254.72004-1-sj@kernel.org> <20260831140254.72004-2-sj@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Mon, 31 Aug 2026 17:45:23 +0000 Message-Id: <20260831174524.53C7A1F000E9@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/20260831140254.7200= 4-1-sj@kernel.org?part=3D1