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 X-Spam-Level: X-Spam-Status: No, score=-18.4 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 51AEBC11F69 for ; Thu, 1 Jul 2021 00:08:08 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id D59A761466 for ; Thu, 1 Jul 2021 00:08:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D59A761466 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id D06EB8D01CD; Wed, 30 Jun 2021 20:08:05 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id CB6C28D01C8; Wed, 30 Jun 2021 20:08:05 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B57748D01CD; Wed, 30 Jun 2021 20:08:05 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0192.hostedemail.com [216.40.44.192]) by kanga.kvack.org (Postfix) with ESMTP id 935C68D01C8 for ; Wed, 30 Jun 2021 20:08:05 -0400 (EDT) Received: from smtpin06.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 5746522865 for ; Thu, 1 Jul 2021 00:08:05 +0000 (UTC) X-FDA: 78312081330.06.DA9390E Received: from mail-lf1-f51.google.com (mail-lf1-f51.google.com [209.85.167.51]) by imf15.hostedemail.com (Postfix) with ESMTP id 1D5DCD000080 for ; Thu, 1 Jul 2021 00:08:04 +0000 (UTC) Received: by mail-lf1-f51.google.com with SMTP id bu19so8372271lfb.9 for ; Wed, 30 Jun 2021 17:08:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=0vibCQHRcBzovbP098YQJ8mdWoX2J5W8wiaM7M9niEQ=; b=e+BOa5lVh8fknuCBWWZJqvx/9unwfYZPGN/BgA6mFJfxXAR3MsYl2UaPqSISg1aemm CckSbHg9T6n+da7WWFpBAZ19uz/mPHl35kTBjAfx3HZ5AJVbYw6XF5KDLJKf5+8dyYf0 eC0MVxMARYtz4R3YUWDRwpdZXUTpJcXAbenKfunsIzgQm82ewVZHwtcsg66USaN7rrs7 Gef0I9NiO3dD+8MHYvBRjrZV8WGIaZ4pu3o85U2v/VMGVXzlsGf91B0I4berjf8tusiK 5SC0NWeI+yuxx9nZHdRM4gFyh/an4RKZOi7AhehE7juhNmVlPDCFBUO3rbEyg87sW8lS jtQA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=0vibCQHRcBzovbP098YQJ8mdWoX2J5W8wiaM7M9niEQ=; b=LI5ibTH3uFPHOmjbf/5ryEfC/E0V9ZDEfB1foMaZ3QLbewm3XcsBO/n1efz4k5v1P1 UjcxRCv2TFk6LoZKZKUW9Snzy+65EHuM95nh1RGdva5HpGIQpXTz6qBUupOFbqeg11IP TIHxS0pd8OzyBVsbardhbfopM3PzxRwwOueHdfnYCpj/WAELuiU3XgTyhhN+UfYQBSBR xdamIy0tFyNxpv3PElVBL0iv/OQ6OS6I97wGg57N88vwIPM/dODVCB+6mhK+alun/Y+K nIqotZ8nGLraTG8WVS2+6BSpRHRC8lN58sFWRvoOFW3BetO+Gb8xOfldxDpk1hG8twYK uJGA== X-Gm-Message-State: AOAM532bT0+lDGoNbdbpTTmXVms3vEjXHhmpUu2cAjPnyqBzHhpAqxVU kL6pNvJOZ4fdmOK0bsrUMZ3jPvaOWzNysCGNkCsQfg== X-Google-Smtp-Source: ABdhPJxmyDJBfSyvbdI9dLWs8zeazyEu5My7Y4TtfaD2ngwyDX1ng6dTOgkazyM8zq5NQfwyTeaMmDjfcRV2sJdGoAs= X-Received: by 2002:a19:5016:: with SMTP id e22mr16576212lfb.299.1625098083067; Wed, 30 Jun 2021 17:08:03 -0700 (PDT) MIME-Version: 1.0 References: <20210628133355.18576-1-sj38.park@gmail.com> <20210628133355.18576-4-sj38.park@gmail.com> In-Reply-To: <20210628133355.18576-4-sj38.park@gmail.com> From: Shakeel Butt Date: Wed, 30 Jun 2021 17:07:51 -0700 Message-ID: Subject: Re: [PATCH v32 03/13] mm/damon: Adaptively adjust regions To: SeongJae Park Cc: Andrew Morton , SeongJae Park , Jonathan.Cameron@huawei.com, acme@kernel.org, alexander.shishkin@linux.intel.com, amit@kernel.org, benh@kernel.crashing.org, Brendan Higgins , Jonathan Corbet , David Hildenbrand , dwmw@amazon.com, Marco Elver , "Du, Fan" , foersleo@amazon.de, greg@kroah.com, Greg Thelen , guoju.fgj@alibaba-inc.com, jgowans@amazon.com, Mel Gorman , mheyne@amazon.de, Minchan Kim , Ingo Molnar , namhyung@kernel.org, "Peter Zijlstra (Intel)" , Rik van Riel , David Rientjes , Steven Rostedt , Mike Rapoport , Shuah Khan , sieberf@amazon.com, snu@zelle79.org, Vlastimil Babka , Vladimir Davydov , zgf574564920@gmail.com, linux-damon@amazon.com, Linux MM , linux-doc@vger.kernel.org, LKML Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 1D5DCD000080 Authentication-Results: imf15.hostedemail.com; dkim=pass header.d=google.com header.s=20161025 header.b=e+BOa5lV; spf=pass (imf15.hostedemail.com: domain of shakeelb@google.com designates 209.85.167.51 as permitted sender) smtp.mailfrom=shakeelb@google.com; dmarc=pass (policy=reject) header.from=google.com X-Stat-Signature: gjfko1fbtcio5b8az6wrqbrrjh3w94td X-HE-Tag: 1625098084-528406 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: On Mon, Jun 28, 2021 at 6:34 AM SeongJae Park wrote: > > From: SeongJae Park > > Even somehow the initial monitoring target regions are well constructed > to fulfill the assumption (pages in same region have similar access > frequencies), the data access pattern can be dynamically changed. This > will result in low monitoring quality. To keep the assumption as much > as possible, DAMON adaptively merges and splits each region based on > their access frequency. > > For each ``aggregation interval``, it compares the access frequencies of > adjacent regions and merges those if the frequency difference is small. > Then, after it reports and clears the aggregated access frequency of > each region, it splits each region into two or three regions if the > total number of regions will not exceed the user-specified maximum > number of regions after the split. > > In this way, DAMON provides its best-effort quality and minimal overhead > while keeping the upper-bound overhead that users set. > > Signed-off-by: SeongJae Park > Reviewed-by: Leonard Foerster > Reviewed-by: Fernand Sieber Acked-by: Shakeel Butt