From nobody Sun Feb 8 16:05:02 2026 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BB41EEB64D7 for ; Fri, 16 Jun 2023 19:21:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345060AbjFPTVq (ORCPT ); Fri, 16 Jun 2023 15:21:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50264 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345417AbjFPTVY (ORCPT ); Fri, 16 Jun 2023 15:21:24 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 515235256; Fri, 16 Jun 2023 12:19:07 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 5B83E637D2; Fri, 16 Jun 2023 19:17:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 36B0FC433C8; Fri, 16 Jun 2023 19:17:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1686943068; bh=l86JWMdvVZwYcsvalUMuaAJbJetoG2ebBMyTen7o1Uk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Qr2d0sNYjVXHU2h2cqGjllyRexevn0t+autu/4Fqlk1gSHpY9elRfUlnnfCb22CC/ RK82KqUj8pDaUCmh8ryWEwzBGIbYN/6c2k397K0rPqsiIJVrhl8bRsXwM+Q78JRv7U 269xagijYdqtqDx/F8VEPtQGJpO3G9VdcRPTHE7by+L7mas3ZcuFDLHQ/99JVsSxyz 1Kn6h1liPOopyFtjUysuO9LFXG0UUSTxBzLoEt+If/QMY8avmU1cTkUNdeHFmSfZeS EpLAqipTwBQROZWN92bRjNy+hxtQe1Alu/SJN9XXXeudr8b93h5JkbgExk1uMLmDFB MjbTIMb3ILl1g== From: SeongJae Park To: Andrew Morton Cc: SeongJae Park , Jonathan Corbet , damon@lists.linux.dev, linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 1/7] Docs/mm/damon/design: document 'age' of region Date: Fri, 16 Jun 2023 19:17:36 +0000 Message-Id: <20230616191742.87531-2-sj@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230616191742.87531-1-sj@kernel.org> References: <20230616191742.87531-1-sj@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" The 'age' of each region in DAMON monitoring results is an important concept for both monitoring part and DAMOS. And DAMOS section of the design document is mentioning it. However, the age itself is not explained in the document. Add a section for that. Signed-off-by: SeongJae Park --- Documentation/mm/damon/design.rst | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/Documentation/mm/damon/design.rst b/Documentation/mm/damon/des= ign.rst index da110e89cab4..a98af99bb705 100644 --- a/Documentation/mm/damon/design.rst +++ b/Documentation/mm/damon/design.rst @@ -190,6 +190,20 @@ In this way, DAMON provides its best-effort quality an= d minimal overhead while keeping the bounds users set for their trade-off. =20 =20 +Age Tracking +~~~~~~~~~~~~ + +By analyzing the monitoring results, users can also find how long the curr= ent +access pattern of a region has maintained. That could be used for good +understanding of the access pattern. For example, page placement algorithm +utilizing both the frequency and the recency could be implemented using th= at. +To make such access pattern maintained period analysis easier, DAMON maint= ains +yet another counter called ``age`` in each region. For each ``aggregation +interval``, DAMON checks if the region's size and access frequency +(``nr_accesses``) has significantly changed. If so, the counter is reset = to +zero. Otherwise, the counter is increased. + + Dynamic Target Space Updates Handling ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ =20 --=20 2.25.1