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]) by smtp.lore.kernel.org (Postfix) with ESMTP id F1F49C021A0 for ; Mon, 17 Feb 2025 08:06:12 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 672A728003D; Mon, 17 Feb 2025 03:06:12 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 6209328003A; Mon, 17 Feb 2025 03:06:12 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5100A28003D; Mon, 17 Feb 2025 03:06:12 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 32FAD28003A for ; Mon, 17 Feb 2025 03:06:12 -0500 (EST) Received: from smtpin30.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id DD55BB5D4D for ; Mon, 17 Feb 2025 08:06:11 +0000 (UTC) X-FDA: 83128703742.30.7034B4F Received: from out30-119.freemail.mail.aliyun.com (out30-119.freemail.mail.aliyun.com [115.124.30.119]) by imf09.hostedemail.com (Postfix) with ESMTP id C507D14000F for ; Mon, 17 Feb 2025 08:06:08 +0000 (UTC) Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=linux.alibaba.com header.s=default header.b=wmKbkXzX; dmarc=pass (policy=none) header.from=linux.alibaba.com; spf=pass (imf09.hostedemail.com: domain of ying.huang@linux.alibaba.com designates 115.124.30.119 as permitted sender) smtp.mailfrom=ying.huang@linux.alibaba.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1739779570; a=rsa-sha256; cv=none; b=dSpQ9uwiTWLZoI0xoHac5K0J8xkzbt/88UEoIbjFIuONCb4rgwm7DKcj0Xgwr/v+Ur0/GM gG+1v4opLPRMh/5OdkdoLp6LMW0s0Evv2zP9uzMFiuP4HK2y88H5dlKI36Vklbr4DwkZZP HsSYlO7GoLR4CupvP/9mygcyBQVo3nU= ARC-Authentication-Results: i=1; imf09.hostedemail.com; dkim=pass header.d=linux.alibaba.com header.s=default header.b=wmKbkXzX; dmarc=pass (policy=none) header.from=linux.alibaba.com; spf=pass (imf09.hostedemail.com: domain of ying.huang@linux.alibaba.com designates 115.124.30.119 as permitted sender) smtp.mailfrom=ying.huang@linux.alibaba.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1739779570; 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-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=sfNxgtmB0/jz3pq8TzZXhfYQ6DAYL0BO+1v9NrYYgkg=; b=R3TgoCWPk9IV3U64LDvaCvTG/K2/03Fr2L9Z/HPg1/xZrfw3DfMzixNG2Rxdts60q65G/g V5rkIlQpt6X/pvXNR8UjCDsy0VQj3wPesTcfITV1BRKapox7Ug6CaVjxzetSLdYcyFe3QN tmN+Z2U0aDz/3fFrRYmJ89mbZxEcoLw= DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1739779565; h=From:To:Subject:Date:Message-ID:MIME-Version:Content-Type; bh=sfNxgtmB0/jz3pq8TzZXhfYQ6DAYL0BO+1v9NrYYgkg=; b=wmKbkXzX5agC6tHZ3aODDJvARy8N2+AWzEYF+tnbwKLM4HvYOqHpkmzKYkykiBSY+QgzQ5M5tscDT50VxzMOlIbJAvm3WXleAtBtFmzjxH800qhIOYCnkMRZ52HWYNy+pV1PdJZpWJHZPw7JPQKa7fFUIGJPNT9Q1w1T6P1Se+Y= Received: from DESKTOP-5N7EMDA(mailfrom:ying.huang@linux.alibaba.com fp:SMTPD_---0WPc6v4i_1739779561 cluster:ay36) by smtp.aliyun-inc.com; Mon, 17 Feb 2025 16:06:03 +0800 From: "Huang, Ying" To: Bharata B Rao Cc: Jonathan Cameron , Raghavendra K T , linux-mm@kvack.org, akpm@linux-foundation.org, lsf-pc@lists.linux-foundation.org, gourry@gourry.net, nehagholkar@meta.com, abhishekd@meta.com, nphamcs@gmail.com, hannes@cmpxchg.org, kbusch@meta.com, Hasan.Maruf@amd.com, sj@kernel.org, david@redhat.com, willy@infradead.org, k.shutemov@gmail.com, mgorman@techsingularity.net, vbabka@suse.cz, hughd@google.com, rientjes@google.com, shy828301@gmail.com, liam.howlett@oracle.com, peterz@infradead.org, mingo@redhat.com, nadav.amit@gmail.com, shivankg@amd.com, ziy@nvidia.com, jhubbard@nvidia.com, AneeshKumar.KizhakeVeetil@arm.com, linux-kernel@vger.kernel.org, jon.grimm@amd.com, santosh.shukla@amd.com, Michael.Day@amd.com, riel@surriel.com, weixugc@google.com, leesuyeon0506@gmail.com, honggyu.kim@sk.com, leillc@google.com, kmanaouil.dev@gmail.com, rppt@kernel.org, dave.hansen@intel.com, feng.tang@linux.alibaba.com Subject: Re: [LSF/MM/BPF TOPIC] Unifying sources of page temperature information - what info is actually wanted? In-Reply-To: (Bharata B. Rao's message of "Mon, 17 Feb 2025 09:40:36 +0530") References: <20250123105721.424117-1-raghavendra.kt@amd.com> <20250131122803.000031aa@huawei.com> <20250131130901.00000dd1@huawei.com> <87h64u2xkh.fsf@DESKTOP-5N7EMDA> Date: Mon, 17 Feb 2025 16:06:01 +0800 Message-ID: <874j0t2dxy.fsf@DESKTOP-5N7EMDA> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain; charset=ascii X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: C507D14000F X-Stat-Signature: e4gh9in99s5nurc8si9xizwats3ug8ws X-Rspam-User: X-HE-Tag: 1739779568-736349 X-HE-Meta: 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 l36pSqHV c5uO8vyDrl7uF9TZeTd/ayUdIopoFMAr90J37b+htZt1yy0eE91rvWjfkhIJ87ml6ZS7LXHbyvW3sWxkPyjhP5VeYzFSjUlI9/jC/fYnKAgX8CXaRJr989e6joMNaL0sk0LsuetroD94kr6LDNNi/rPQZQ1fgmyGxsPVGqMyHxfY/EWI5RmRchE5BW88cFPSrwsirc7ItQOyiXiMgUEtGRdY59LYbMtUyPz1/wyGDJAeVRQ3qyxkXnujJMEKYawx8ojHJBgxP8KFs97D7DZ9HHThaXS1kDgWQXshgvAz1RY2x13/LFnKm4nbyxcGq6mODqEmundu514FswsvMQ0G6D0U+bBJxVk2pqFqq X-Bogosity: Ham, tests=bogofilter, spamicity=0.000227, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Bharata B Rao writes: > On 16-Feb-25 12:19 PM, Huang, Ying wrote: >>>> >>>> 1) Give me up to X hotish pages from a slow tier (greater than a specific measure >>>> of temperature) >> Because the hot pages may be available upon page accessing (such >> PROT_NONE >> page fault), the interface may be "push" style instead of "pull" style, >> e.g., >> int register_hot_page_handler(void (*handler)(struct page *hot_page, >> int temperature)); > > Yes, push model appears natural to me given that there are producers > who are themselves consumers as well. > > Let's take an example of access being detected by PTE scan by DAMON > first and LRU and hot page promotion subsystems have registered > handlers for hot page info. > > Now if hot page promotion handler gets called first and if it promotes > the page, calling LRU registered handler still makes sense? May be not > I suppose. > > On the other hand if LRU subsystem handler gets first and it > adjusts/modifies the hot page's list, it would still make sense to > activate the hot page promotion handler to check for possible > promotion. > > Is this how you are envisioning the different consumers of hot page > access info could work/cooperate? Sorry, I have no idea about what is the right behavior now. It appears hard to coordinate different consumers. In theory, we can promote the hottest pages while activate (in LRU lists) the warm pages. --- Best Regards, Huang, Ying