From patchwork Fri Nov 5 20:46:39 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 12605857 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DFF59C433FE for ; Fri, 5 Nov 2021 20:46:42 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 9AE866136A for ; Fri, 5 Nov 2021 20:46:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 9AE866136A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id 342E69400DE; Fri, 5 Nov 2021 16:46:42 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 2F2919400C1; Fri, 5 Nov 2021 16:46:42 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1BB2D9400DE; Fri, 5 Nov 2021 16:46:42 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0194.hostedemail.com [216.40.44.194]) by kanga.kvack.org (Postfix) with ESMTP id 062DE9400C1 for ; Fri, 5 Nov 2021 16:46:42 -0400 (EDT) Received: from smtpin05.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id BB10E8249980 for ; Fri, 5 Nov 2021 20:46:41 +0000 (UTC) X-FDA: 78776060328.05.C8DC38C Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf17.hostedemail.com (Postfix) with ESMTP id 43C5AF0003B8 for ; Fri, 5 Nov 2021 20:46:41 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id DB46061288; Fri, 5 Nov 2021 20:46:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1636145200; bh=i5KSwLkZjkyCOOiADrAkxZ/QTlmqwFS8Uohf6C0QEas=; h=Date:From:To:Subject:In-Reply-To:From; b=h6NySITDANK3Tkxi73/gteFnR3d4gPWPZaBv5l5XG0p4R5upjPv7XWzqJKoxZ3SEX /veD3QB0qu0QButXYL0UWkCnvQh1F1U6oa8wa4iKaMfj7xK2wQ+HyM6dudtYWrOO6x 3kkxv4bbwZ2LMFIs5C+plAiaJ20rSH8aXc5urfZk= Date: Fri, 05 Nov 2021 13:46:39 -0700 From: Andrew Morton To: akpm@linux-foundation.org, amit@kernel.org, benh@kernel.crashing.org, corbet@lwn.net, david@redhat.com, dwmw@amazon.com, elver@google.com, foersleo@amazon.de, gthelen@google.com, Jonathan.Cameron@huawei.com, linux-mm@kvack.org, markubo@amazon.de, mm-commits@vger.kernel.org, rientjes@google.com, shakeelb@google.com, shuah@kernel.org, sj@kernel.org, torvalds@linux-foundation.org Subject: [patch 229/262] Docs/admin-guide/mm/damon: document DAMON-based Operation Schemes Message-ID: <20211105204639.Cba_-vH9D%akpm@linux-foundation.org> In-Reply-To: <20211105133408.cccbb98b71a77d5e8430aba1@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 43C5AF0003B8 X-Stat-Signature: 8m98ua4dam8k6aejuxj8k8j6q69h9z1m Authentication-Results: imf17.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=h6NySITD; dmarc=none; spf=pass (imf17.hostedemail.com: domain of akpm@linux-foundation.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org X-HE-Tag: 1636145201-942334 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: From: SeongJae Park Subject: Docs/admin-guide/mm/damon: document DAMON-based Operation Schemes This commit add description of DAMON-based operation schemes in the DAMON documents. Link: https://lkml.kernel.org/r/20211001125604.29660-8-sj@kernel.org Signed-off-by: SeongJae Park Cc: Amit Shah Cc: Benjamin Herrenschmidt Cc: David Hildenbrand Cc: David Rienjes Cc: David Woodhouse Cc: Greg Thelen Cc: Jonathan Cameron Cc: Jonathan Corbet Cc: Leonard Foerster Cc: Marco Elver Cc: Markus Boehme Cc: Shakeel Butt Cc: Shuah Khan Signed-off-by: Andrew Morton --- Documentation/admin-guide/mm/damon/start.rst | 11 +++ Documentation/admin-guide/mm/damon/usage.rst | 51 ++++++++++++++++- 2 files changed, 60 insertions(+), 2 deletions(-) --- a/Documentation/admin-guide/mm/damon/start.rst~docs-admin-guide-mm-damon-document-damon-based-operation-schemes +++ a/Documentation/admin-guide/mm/damon/start.rst @@ -108,6 +108,17 @@ the results as separate image files. :: You can view the visualizations of this example workload at [1]_. Visualizations of other realistic workloads are available at [2]_ [3]_ [4]_. + +Data Access Pattern Aware Memory Management +=========================================== + +Below three commands make every memory region of size >=4K that doesn't +accessed for >=60 seconds in your workload to be swapped out. :: + + $ echo "#min-size max-size min-acc max-acc min-age max-age action" > scheme + $ echo "4K max 0 0 60s max pageout" >> scheme + $ damo schemes -c my_thp_scheme + .. [1] https://damonitor.github.io/doc/html/v17/admin-guide/mm/damon/start.html#visualizing-recorded-patterns .. [2] https://damonitor.github.io/test/result/visual/latest/rec.heatmap.1.png.html .. [3] https://damonitor.github.io/test/result/visual/latest/rec.wss_sz.png.html --- a/Documentation/admin-guide/mm/damon/usage.rst~docs-admin-guide-mm-damon-document-damon-based-operation-schemes +++ a/Documentation/admin-guide/mm/damon/usage.rst @@ -34,8 +34,8 @@ the reason, this document describes only debugfs Interface ================= -DAMON exports three files, ``attrs``, ``target_ids``, and ``monitor_on`` under -its debugfs directory, ``/damon/``. +DAMON exports four files, ``attrs``, ``target_ids``, ``schemes`` and +``monitor_on`` under its debugfs directory, ``/damon/``. Attributes @@ -74,6 +74,53 @@ check it again:: Note that setting the target ids doesn't start the monitoring. +Schemes +------- + +For usual DAMON-based data access aware memory management optimizations, users +would simply want the system to apply a memory management action to a memory +region of a specific size having a specific access frequency for a specific +time. DAMON receives such formalized operation schemes from the user and +applies those to the target processes. It also counts the total number and +size of regions that each scheme is applied. This statistics can be used for +online analysis or tuning of the schemes. + +Users can get and set the schemes by reading from and writing to ``schemes`` +debugfs file. Reading the file also shows the statistics of each scheme. To +the file, each of the schemes should be represented in each line in below form: + + min-size max-size min-acc max-acc min-age max-age action + +Note that the ranges are closed interval. Bytes for the size of regions +(``min-size`` and ``max-size``), number of monitored accesses per aggregate +interval for access frequency (``min-acc`` and ``max-acc``), number of +aggregate intervals for the age of regions (``min-age`` and ``max-age``), and a +predefined integer for memory management actions should be used. The supported +numbers and their meanings are as below. + + - 0: Call ``madvise()`` for the region with ``MADV_WILLNEED`` + - 1: Call ``madvise()`` for the region with ``MADV_COLD`` + - 2: Call ``madvise()`` for the region with ``MADV_PAGEOUT`` + - 3: Call ``madvise()`` for the region with ``MADV_HUGEPAGE`` + - 4: Call ``madvise()`` for the region with ``MADV_NOHUGEPAGE`` + - 5: Do nothing but count the statistics + +You can disable schemes by simply writing an empty string to the file. For +example, below commands applies a scheme saying "If a memory region of size in +[4KiB, 8KiB] is showing accesses per aggregate interval in [0, 5] for aggregate +interval in [10, 20], page out the region", check the entered scheme again, and +finally remove the scheme. :: + + # cd /damon + # echo "4096 8192 0 5 10 20 2" > schemes + # cat schemes + 4096 8192 0 5 10 20 2 0 0 + # echo > schemes + +The last two integers in the 4th line of above example is the total number and +the total size of the regions that the scheme is applied. + + Turning On/Off --------------