From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 4685932D5CF; Tue, 16 Sep 2025 18:31:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758047491; cv=none; b=ZHZ2Z8EjE3RhOb4YRi6pVrUGiPSxAWfo+HFMmKQGGoQ4AN1GpP074fFXAjcFcRWb44NT25KZtd0H+9nbcWL9zA7fUNnpwP2SBpb5Mj0T5iHIEqKBz059ZI9KSttX0rkgY3P7XEHrr2NiiqCujG6LVCpKL7xd/Axn60Mz5mO1Ibo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758047491; c=relaxed/simple; bh=zRA7NzE2dfOJUv7we74p+H9MxXbTZALm/bBalZg7Shw=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=JeHxZoAwDRHysU7dJoR7xey0IPQTnErVsopQTVHPOTxXI0Zn5I88xzHtVivtXKss8ld6farXyvF30XGv0CWoW17GWeYHGz17RsDvjykab4Noo5T5qDu/9q86VZ+b6OcLT+8IxhXPZvK9LJUYHPqC+aTmDdqn6Fy+RrUidsJhzlA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=A9gb090R; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="A9gb090R" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AA99EC4CEEB; Tue, 16 Sep 2025 18:31:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1758047490; bh=zRA7NzE2dfOJUv7we74p+H9MxXbTZALm/bBalZg7Shw=; h=From:To:Cc:Subject:Date:From; b=A9gb090RsE07mCO9Y33W/36nq4GLOSQVtHGp+4RNpeKz96L1yb8NUM5809CbwhRhN IxmkXRoJL9LJBtYW8PNSiCMb+C0wRjwa6Vvzwy3w9+CqKJTJK/eJ7IgbjpUqJuqxs1 kBa5QnQrlM+Gdx+iZ7O99oOSbab8DRCV+dljqnZcDyeOqPJUq2t7WgbzP4avJ/D9L9 4Ut5iyrgsFTWrUzSWnoj0ql+UkexNrn1YZAYyAqS389OOhSzTWef1ZE2bSRYBIPgiM 367w6e3Y9Vf47Cb6YyFvKam+Bs5P5Jmc/3tKQsWrEQ3uDYS1Z9WSaC5JzIREKSZvK1 eQ5Vj07ObeI+w== From: SeongJae Park To: Andrew Morton Cc: SeongJae Park , damon@lists.linux.dev, kernel-team@meta.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH 0/2] mm/damon/stat: expose auto-tuned intervals and non-idle ages Date: Tue, 16 Sep 2025 11:31:25 -0700 Message-Id: <20250916183127.65708-1-sj@kernel.org> X-Mailer: git-send-email 2.39.5 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit DAMON_STAT is intentionally providing limited information for easy consumption of the information. From production fleet level usages, below limitations are found, though. The aggregation interval of DAMON_STAT represents the granularity of the memory_idle_ms_percentiles. But the interval is auto-tuned and not exposed to users, so users cannot know the granularity. All memory regions of non-zero (positive) nr_accesses are treated as having zero idle time. A significant portion of production systems have such zero idle time. Hence breakdown of warm and hot data is nearly impossible. Make following changes to overcome the limitations. Expose the auto-tuned aggregation interval with a new parameter named aggr_interval_us. Expose the age of non-zero nr_accesses (how long >0 access frequency the region retained) regions as a negative idle time. Changes from RFC (https://lore.kernel.org/20250910040022.168223-1-sj@kernel.org) - Rebase on latest mm-new - Wordsmith commit messages SeongJae Park (2): mm/damon/stat: expose the current tuned aggregation interval mm/damon/stat: expose negative idle time mm/damon/stat.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) base-commit: ae4745146347aef91dc328d1d9a39f0643ee244d -- 2.39.5