From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794082586; b=gzTaaSZpwaomjOpUa6xS0lg1B6xX/K39ho+N1ppVAQwk3Zn5OqZFJvXYJ/naIEn554jM c4tb4T2Y0BKf5Xc/YePkYnVUiRcItYA6OJDWaLGO46lQMjJLDZtc1hWWZIU2tXK9oV5Hs b0+dlMzA/rYZrHwgXaPXg8g6zjmG+BypuTirqGvwGPuhCZ8yRPBGQjMng+aPRa2Jzu7dJ p7tf3STPLJS/nXnG/J/yO7no7Jsqy1qCKJ5J4sSbePBRvAxBh+ezMbcu2WAKgfa+fvUt5 XjqN7MD3s8diqroAtzUfPpEKBHwFhtEN/wOIMKcll6/PQJa+6YeRmFhqi4NG8b/Jheg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794082586; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=M7g2pr3kkD/CSWJUpDzGgViLett+jFEZktD5nsKbj1s=; b=i/yTJCS62b1oDsMaNKE1sTm0MtSOnyBG3AyWaVtHz1ZAaufMnwW7kxq+Zz8QPnJoCUKy 44WP/Oc3xi8wwdTx1ln7YGxMAzbE8zDRSMIg+sYTmF5il/sm4Z6Bvo4VhHCyQYF55x+/6 DrGfa8dG0fV0jAck6ufQDLSi3lYz17zlBf9E2pHD65WMoZT9nXEIU3rwm3P1ezK+I2fy5 Y0LlW9S0wzFR5y2MoCcvKq0AcRVjGgLWu93M0+QX14qU/Lf53GdyFeXgYCUgGgPYJe0bP 0GsrINgOZi6IXwyTitETcyvg+uEvC7srO9WOpfZ/yLgtf1x5gwXPhnKfFGSHmLYCSmg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b="YA//QQ1G"; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 94B78606A331 for ; Sat, 7 Nov 2026 20:16:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=YA//QQ1G Received: by smtp.kernel.org (Postfix) with ESMTPSA id 391D91F0089F; Sat, 7 Nov 2026 20:16:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794082586; bh=M7g2pr3kkD/CSWJUpDzGgViLett+jFEZktD5nsKbj1s=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=YA//QQ1GrkHwK19OK91/wAhu1y+2ZKJWaKNB+bPnpNQ2zWz/6gWBi6RBt7EEjPfnB apd6s0nIuN7r59bbYvUBzwCPk1B3Yc4cCuKC+7hDYGVlnB50MnXz+BEtrAvm7g4L3p u/UxDPJkLpmc0ARmBZHEbr17GwZQOYA3tXE2YF3kNaPTjumg4B/eohsDe7BnqDhMxr Zb/IgGRcElgGtzlOivirPagg2Y/s0BMQT6d6nRSG3aANYkNR+05cpforrkiRypkEBj pSg9+BDi2Z4EwNjL8QOJkGZexBkh1urjWnZRLvd6QLmLfNte3waxyzWxR5qkMhE6jN kFhDhnuLW5L3w== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [RFC PATCH 6.18.y 2/5] mm/damon/core: handle uninitialized damos_quota_goal->last_psi_total Reply-To: sashiko-reviews@lists.linux.dev To: "SJ Park" Cc: damon@lists.linux.dev In-Reply-To: <20261107201001.206120-3-sj@kernel.org> References: <20261107201001.206120-1-sj@kernel.org> <20261107201001.206120-3-sj@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Sat, 07 Nov 2026 20:16:25 +0000 X-Mailing-List: damon@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list > When DAMOS_QUOTA_SOME_MEM_PSI_US metric damos quota goal is set, the PSI > delta for the feedback loop is calculated using > damos_quota_goal->last_psi_total. However, it is initialized only after > the first feedback loop. The first iteration of the loop uses the > uninitialized value. As a result, the feedback loop can change the > effective quota in an unexpected way at the first iteration. >=20 > The user impact of the issue is not big, because the issue impacts only > the first iteration of the feedback loop. The feedback loop also has an > internal cap of the quota adjustment. The wrong adjustment will soon be > corrected over a few iterations. For this reason, doing no initialization > at commit time was intentional. It is also explicitly commented. That > said, nobody likes behaviors that are unexpected or difficult to be > expected. >=20 > [ ... ] > Cc: David Gow > Cc: Quanmin Yan > Cc: # 6.9.x > (cherry picked from commit 29c6084658af41b5b1fefd873d26d441830ced34) > Signed-off-by: SJ Park Sashiko has reviewed this patch and found no issues. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261107201001.2061= 20-1-sj@kernel.org?part=3D2