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=1794166279; b=EgsypMT8ZgnjMyf/Cue9O+hVTLETOYjizORLGhU5quWY1Pd5pps3YN/EQzgESKm58lfg y2FrwlDAhB2tIiYfiahKzucuFrX/61AI0ylM1jsaSNNoDDJO5WOEFBDv06czahDS4n4u4 CusNDVDu3wRytUOoIo8Ab4t00nz912+ksYrNYrsaP7JSu3P1k9sf60OtVa8W8q7jJeccz xGYqNz9Qf6mDT68jOgab54utUfPTKojxLqDHB7FrZCvzKdU1UofuIO3Akfu/eJTZwWqSG gKTdQ3QH65Ktv9GpjHRcFA/Of/m5q6BUhIGTc2s6smMbkblxTk9uPUn16NXs6V6zo3Q== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794166279; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=BB3A9xh2PwWiMuZdlCcP7QL1sFk/1dQfwvriK/6BS2g=; b=wLMX8VwN3WPARO9/kNubGda3LEeAPv/atDESq/KWqNRtCceaRNu+3Nhn+RsSbXAAq0Os uEZFZ3A6OeH++0q/p6RU1yiYQcVxuJXkAO61js0KCkofcQGiqYBfNM1GVHkrR8NPJSIql mrSNW/kXlFXUD5utn4YUARLMOILSnxLK8WH7RMdIqDuQvUSEQwJbD8iqU7pU9tzg+2NCU YlXReyztcMqhDm8p+uG4J8eou6F8UfrNtoRVBG8W0JEckfPdMzl11gkRnqRwyl1AfYMuO W8Xm2oKSWncmdh7ur8gTi705d5eDUHfMU+9KbXI2ggvMb4r8JIiyVgTZWF7m9WJvPrg== 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=njzFSdbL; 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 2F4EF606A320 for ; Sun, 8 Nov 2026 19:31:19 +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=njzFSdbL Received: by smtp.kernel.org (Postfix) with ESMTPSA id E006B1F0089F; Sun, 8 Nov 2026 19:31:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794166279; bh=BB3A9xh2PwWiMuZdlCcP7QL1sFk/1dQfwvriK/6BS2g=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=njzFSdbLsNVTrFsqXxqItD5d9N+tHWl106IBzcswDSyN4NZrQ2b3BkMlMQnhLDU+Y boDk2oQ+31Tm9iRoOw4gxln1Uk4u7vy2fgEPHSIRxYqph3XERRIXTrVC0HS2wMH1ON 8VRWOyZUac7eF2jv0VMPS1ZxooOnMuTfDX9TnCA1LcnFRg+qgyxHd3tHEDwVGAyFfK ntPrYCI6NynAzTOsPABnQQjFhuOTKpVUYnK+bVAcT7I9VLu66J4lQwWthspOxclmrl rz8rHUmPDFHjUrwSmlRtVMa9hxmB3Tn8Q/0hRmoTds1zF8Xpts/7pKtUmtNBqiiULu 3Vc29s0Gvosbg== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [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: <20261108192221.114362-3-sj@kernel.org> References: <20261108192221.114362-1-sj@kernel.org> <20261108192221.114362-3-sj@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Sun, 08 Nov 2026 19:31:18 +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/20261108192221.1143= 62-1-sj@kernel.org?part=3D2