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=-6.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 06F28C433E2 for ; Thu, 18 Jun 2020 09:24:00 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id C12D321D7E for ; Thu, 18 Jun 2020 09:23:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="LWQ/Rf0f" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C12D321D7E Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=amazon.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id A954B8D0002; Thu, 18 Jun 2020 05:23:58 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 961438D0001; Thu, 18 Jun 2020 05:23:58 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 825B36B0070; Thu, 18 Jun 2020 05:23:58 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0212.hostedemail.com [216.40.44.212]) by kanga.kvack.org (Postfix) with ESMTP id 5DECC6B0068 for ; Thu, 18 Jun 2020 05:23:58 -0400 (EDT) Received: from smtpin22.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 25F22A8C1 for ; Thu, 18 Jun 2020 09:23:58 +0000 (UTC) X-FDA: 76941795756.22.stamp41_2c000d126e0f Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin22.hostedemail.com (Postfix) with ESMTP id EF9F218038E60 for ; Thu, 18 Jun 2020 09:23:57 +0000 (UTC) X-HE-Tag: stamp41_2c000d126e0f X-Filterd-Recvd-Size: 4201 Received: from smtp-fw-4101.amazon.com (smtp-fw-4101.amazon.com [72.21.198.25]) by imf22.hostedemail.com (Postfix) with ESMTP for ; Thu, 18 Jun 2020 09:23:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1592472237; x=1624008237; h=from:to:cc:subject:date:message-id:in-reply-to; bh=mwc39JT7lEE4KuagndIAD1fHOgAiEu1k9Z0qdaYumW8=; b=LWQ/Rf0fYeCSKc17YJLjlZSA/ZXEaBoi6u/HDso2mhoLUh88C8kxkIz9 DqA+DcK+ARJTrikNW5psfR72F9JEBdbn0M0fyq0NtFMyaDoZSi/VcepZM YyyIWlBJhlCZlguflcUzo2qcSt3nqZAp3l4+MZRcXw6mf+kySuV8xkE3o w=; IronPort-SDR: 0k3bnbnOOC0ibSwUWEaAqbTA//k6JgCWBRROlxjeVKPOkcJsF5nR8ujzxI8+lOF23Mb6zLeAqQ oLi3j0MLsW0w== X-IronPort-AV: E=Sophos;i="5.73,526,1583193600"; d="scan'208";a="36992751" Received: from iad12-co-svc-p1-lb1-vlan3.amazon.com (HELO email-inbound-relay-1a-16acd5e0.us-east-1.amazon.com) ([10.43.8.6]) by smtp-border-fw-out-4101.iad4.amazon.com with ESMTP; 18 Jun 2020 09:23:55 +0000 Received: from uc85b765ebdd8595b4b67.ant.amazon.com (iad7-ws-svc-lb50-vlan3.amazon.com [10.0.93.214]) by email-inbound-relay-1a-16acd5e0.us-east-1.amazon.com (Postfix) with ESMTPS id 602E7A2134; Thu, 18 Jun 2020 09:23:43 +0000 (UTC) Received: from uc85b765ebdd8595b4b67.ant.amazon.com (localhost [127.0.0.1]) by uc85b765ebdd8595b4b67.ant.amazon.com (8.15.2/8.15.2/Debian-3) with ESMTP id 05I9NeHI022756; Thu, 18 Jun 2020 11:23:40 +0200 Received: (from foersleo@localhost) by uc85b765ebdd8595b4b67.ant.amazon.com (8.15.2/8.15.2/Submit) id 05I9Ndau022754; Thu, 18 Jun 2020 11:23:39 +0200 From: Leonard Foerster To: SeongJae Park Cc: akpm@linux-foundation.org, SeongJae Park , Jonathan.Cameron@Huawei.com, aarcange@redhat.com, acme@kernel.org, alexander.shishkin@linux.intel.com, amit@kernel.org, benh@kernel.crashing.org, brendan.d.gregg@gmail.com, brendanhiggins@google.com, cai@lca.pw, colin.king@canonical.com, corbet@lwn.net, dwmw@amazon.com, foersleo@amazon.de, irogers@google.com, jolsa@redhat.com, kirill@shutemov.name, mark.rutland@arm.com, mgorman@suse.de, minchan@kernel.org, mingo@redhat.com, namhyung@kernel.org, peterz@infradead.org, rdunlap@infradead.org, riel@surriel.com, rientjes@google.com, rostedt@goodmis.org, sblbir@amazon.com, shakeelb@google.com, shuah@kernel.org, sj38.park@gmail.com, snu@amazon.de, vbabka@suse.cz, vdavydov.dev@gmail.com, yang.shi@linux.alibaba.com, ying.huang@intel.com, david@redhat.com, linux-damon@amazon.com, linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v16 04/14] mm/damon: Adaptively adjust regions Date: Thu, 18 Jun 2020 11:23:38 +0200 Message-Id: <1592472218-22708-1-git-send-email-foersleo@amazon.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <20200615161927.12637-5-sjpark@amazon.com> X-Rspamd-Queue-Id: EF9F218038E60 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam02 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 2020-06-15T18:19:17+02:00 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. > > 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 third regions of random > size, if the total number of regions after the splits wouldn't exceed > the user-specified maximum number of regions. > > In this way, DAMON provides its best-effort quality and minimal overhead > while keeping the overhead bound. > > Signed-off-by: SeongJae Park > --- Reviewed-by: Leonard Foerster