From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7BAC6D5B161 for ; Tue, 16 Dec 2025 08:01:46 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 907B66B0005; Tue, 16 Dec 2025 03:01:45 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 8B5286B0093; Tue, 16 Dec 2025 03:01:45 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7B45F6B0095; Tue, 16 Dec 2025 03:01:45 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 65ACC6B0005 for ; Tue, 16 Dec 2025 03:01:45 -0500 (EST) Received: from smtpin06.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 23C76160528 for ; Tue, 16 Dec 2025 08:01:45 +0000 (UTC) X-FDA: 84224590170.06.598E1B3 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf19.hostedemail.com (Postfix) with ESMTP id C8BE71A0016 for ; Tue, 16 Dec 2025 08:01:43 +0000 (UTC) Authentication-Results: imf19.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=UWZCY4TQ; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf19.hostedemail.com: domain of sj@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=sj@kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1765872103; a=rsa-sha256; cv=none; b=SHA7vN10ZO6L2aryBwK0s1S6oLE0kHWjL18x+XaGA3BfIpxezeM81EhiI0XxvQGldZROl+ J1ETffX/eSCgoZb0v2z5Z0z4NokfiSyVo8ANaRJixjw6DVY9BoPcF/j3z1a9cXzwPtv+DA 8sDw9SIc0hua+Jf9BjGiBIg5SaUghOU= ARC-Authentication-Results: i=1; imf19.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=UWZCY4TQ; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf19.hostedemail.com: domain of sj@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=sj@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1765872103; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:references:dkim-signature; bh=rxGaZB5SFBcuHFam7l39Swmr17iB5g/PJOaY8gqTPqU=; b=dRjptgxFXOmYMWtScgQO8Qc0GIn7X/SQ5qN7u+9pPi0i5hNe3/1Y7s1odfCY5fDV+0hYX0 2XPFDqCSJa/TQN3r/4/9V+Wwqd21asGhDN8OZ0LUHZcUt8xbywXmcfRtLEwUffUgGN7KkP 8jT783yQeVL00AzjeD7YynnTqi9mdlA= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 361B960144; Tue, 16 Dec 2025 08:01:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id F0B35C4CEF1; Tue, 16 Dec 2025 08:01:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1765872102; bh=qBAnD+Vuikt86PoF0RLrT+1nqQxfYAOJ8cjFF9lggmw=; h=From:To:Cc:Subject:Date:From; b=UWZCY4TQay0i5+f+wObSpeovHyzE1AdyiiPhBbA+OBybOaKJBOffvzeD1Qmc3CuXx /Nv7hIPp3glvMnqXL9ielgEGo9SuGCCd1M0wxcC6XXco9prMW4wgSEMMfG1VH0Z/nR l7dzXAvU0vbkYoZIJZFM7altOH0pGtMStIhHjDNaa6IWTSGgVyym3WEzGnJMSqha8a Hj1DGkXIemcaxBNGUAZt5SIMwvGsXAyDIDKGJS3+E6nwglFWQFy5wI+Vgrm/UfFrMq dlmUcGU8xj0NcwPCoW6GUZF9l/i6dNITXiplFFAsbLYjolGR5tRN+lupGAuGuwz1vR jeyDiyXvJ/6pA== From: SeongJae Park To: Andrew Morton Cc: SeongJae Park , "Liam R. Howlett" , David Hildenbrand , Jonathan Corbet , Lorenzo Stoakes , Masami Hiramatsu , Mathieu Desnoyers , Michal Hocko , Mike Rapoport , Steven Rostedt , Suren Baghdasaryan , Vlastimil Babka , damon@lists.linux.dev, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org Subject: [PATCH 00/12] mm/damon: introduce {,max_}nr_snapshots and tracepoint for damos stats Date: Tue, 16 Dec 2025 00:01:13 -0800 Message-ID: <20251216080128.42991-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: C8BE71A0016 X-Stat-Signature: ddya747czwnuopx3n486n3wtm6im76qw X-Rspam-User: X-Rspamd-Server: rspam06 X-HE-Tag: 1765872103-475372 X-HE-Meta: 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 brGRdylZ RddYq X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Introduce three changes for improving DAMOS stat's provided information, deterministic control, and reading usability. DAMOS provides stats that are important for understanding its behavior. It lacks information about how many DAMON-generated monitoring output snapshots it has worked on. Add a new stat, nr_snapshots, to show the information. Users can control DAMOS schemes in multiple ways. Using the online parameters commit feature, they can install and uninstall DAMOS schemes whenever they want while keeping DAMON runs. DAMOS quotas and watermarks can be used for manually or automatically turning on/off or adjusting the aggressiveness of the scheme. DAMOS filters can be used for applying the scheme to specific memory entities based on their types and locations. Some users want their DAMOS scheme to be applied to only specific number of DAMON snapshots, for more deterministic control. One example use case is tracepoint based snapshot reading. Add a new knob, max_nr_snapshots, to support this. If the nr_snapshots parameter becomes same to or greater than the value of this parameter, the scheme is deactivated. Users can read DAMOS stats via DAMON's sysfs interface. For deep level investigations on environments having advanced tools like perf and bpftrace, exposing the stats via a tracepoint can be useful. Implement a new tracepoint, namely damon:damos_stat_after_apply_interval. First five patches (patches 1-5) of this series implement the new stat, nr_snapshots, on the core layer (patch 1), expose on DAMON sysfs user interface (patch 2), and update documents (patches 3-5). Following six patches (patches 6-11) are for the new stat based DAMOS deactivation (max_nr_snapshots). The first one (patch 6) of this group updates a kernel-doc comment before making further changes. Then an implementation of it on the core layer (patch 7), an introduction of a new DAMON sysfs interface file for users of the feature (patch 8), and three updates of the documents (patches 9-11) follow. The final one (patch 12) introduces the new tracepoint that exposes the DAMOS stat values for each scheme apply interval. Revision History ---------------- Changes from RFC (https://lore.kernel.org/20251123184329.85287-1-sj@kernel.org) - Check damos_stat tracepoint enablement inside the trace function. - Update ABI document's 'Date:' fields. - Slightly change series subject. SeongJae Park (12): mm/damon/core: introduce nr_snapshots damos stat mm/damon/sysfs-schemes: introduce nr_snapshots damos stat file Docs/mm/damon/design: update for nr_snapshots damos stat Docs/admin-guide/mm/damon/usage: update for nr_snapshots damos stat Docs/ABI/damon: update for nr_snapshots damos stat mm/damon: update damos kerneldoc for stat field mm/damon/core: implement max_nr_snapshots mm/damon/sysfs-schemes: implement max_nr_snapshots file Docs/mm/damon/design: update for max_nr_snapshots Docs/admin-guide/mm/damon/usage: update for max_nr_snapshots Docs/ABI/damon: update for max_nr_snapshots mm/damon/core: add trace point for damos stat per apply interval .../ABI/testing/sysfs-kernel-mm-damon | 13 ++++++ Documentation/admin-guide/mm/damon/usage.rst | 11 ++--- Documentation/mm/damon/design.rst | 7 +++ include/linux/damon.h | 12 ++++-- include/trace/events/damon.h | 41 ++++++++++++++++++ mm/damon/core.c | 39 +++++++++++++++-- mm/damon/sysfs-schemes.c | 43 +++++++++++++++++++ 7 files changed, 155 insertions(+), 11 deletions(-) base-commit: 37164b8fc049b9a72b3f0fa9bf3241e8852931a9 -- 2.47.3