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a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1792073110; b=TurRz8OStfCq17/K3nbs5IzyafMWRJjCu/Oflp7dnbkKymw7BxNFfouij2Q69G0JbNu8uZ csCOm7ervE7KUmoIvEUMMPBX3vPBWWIlkj+0i7eN7njNDCU9/zYsYNtKBWE0+TBamgCJmN c1vlmGXQDPdm4LE4Nntx0RXGiZP+lq4= ARC-Authentication-Results: i=1; imf13.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=Tnslj58V; spf=pass (imf13.hostedemail.com: domain of sj@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=sj@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 33829416EA; Thu, 15 Oct 2026 14:05:09 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DCE891F000C6; Thu, 15 Oct 2026 14:05:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792073109; bh=5ocp4Et+sK/z58kpgz7L+Txb0eSLyo+tHlzKReRnPCk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Tnslj58VcWVpVH2J5Em3kGZqb2Lv4pzwZPtldGD6fzcLiFwsjPKtWdAsQZkqfue0H q00IUB0TkvRYKIgWrzOBh40ZHTyE+yumCC83Kh3a4i23PUYwQmkyu8sKarYwII/AUk Wj0yW11JgnqZUMdpMcycBUwI5wglVWWoPVhckHTzt2zx5zNbFmw0QzlNehMyhnKHk3 vOiFHoRdFXUX4NJ2FmDrVjLlWrEoiAYXF+sk2KbRbW2sqHj0q0jFtz2K/lN9Lh6tCw 5atdSz442mcHmcBok5QP2DHIuOkz8reEfp/1+cIArP7LybmAgo0VsSmSZRAblYCi7g zCWLXW/5CPIUQ== From: SJ Park To: Aveline Noir Cc: SJ Park , Andrew Morton , damon@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [BUG] DAMON sysfs: failed update clears tried_regions snapshot Date: Thu, 15 Oct 2026 07:05:01 -0700 Message-ID: <20261015140502.87975-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 30D8620010 X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: aa9y189xmcx8zx1fri74k6b35i4t46rg X-HE-Tag: 1792073110-347774 X-HE-Meta: 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 BtG8KXUk 3G6FHxagA/pDvbuPVMAc0FjXcVSUSJokSE7x58W53e7h9hevdNq5UCJ9cRsx33OWerblnIQ3u6kMGPVc0dH/sLBbJZJpfIVoYGYkf9EbFetKkUbCZWCOZ0AK5nmeMhl2ym+kkPaVwSlpzCRD7TGpPamc1N4sZrsd8e/8yInIHW30DE5xy/kMI4GtU1o0Nu5OMtTsGeXX4d2IOIgK5IgltbWby/JeO2qGtXk39Sr52hxQJwRVcS+DUjvApRzPd1YrR7ZtGQX88H5oHi167yX318hp6ag== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hi Avelin, On Thu, 15 Oct 2026 07:22:38 -0400 Aveline Noir wrote: > Hi, > > On mm-new commit ad9f2d463666, requesting > update_schemes_tried_regions after stopping a kdamond returns > -ECANCELED and clears the previous tried_regions snapshot. The final > result collected before "off" is then lost. Could you further share your use case that this behavior becomes a real problem? Also, have you tried bisecting this to find from when this behavior was introduced? If so, could you share the commit that introduced this behavior? THanks, SJ [...]