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 C9390C02196 for ; Fri, 7 Feb 2025 09:51:16 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 362A36B0082; Fri, 7 Feb 2025 04:51:16 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 312C96B0093; Fri, 7 Feb 2025 04:51:16 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1DAF1280001; Fri, 7 Feb 2025 04:51:16 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 01E866B0082 for ; Fri, 7 Feb 2025 04:51:15 -0500 (EST) Received: from smtpin11.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 5ECF81A1513 for ; Fri, 7 Feb 2025 09:51:08 +0000 (UTC) X-FDA: 83092680216.11.433B539 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf20.hostedemail.com (Postfix) with ESMTP id B5BFC1C000C for ; Fri, 7 Feb 2025 09:51:06 +0000 (UTC) Authentication-Results: imf20.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=NUS6vtz6; spf=none (imf20.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1738921866; 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=I3zHKIIrHLZPRQJg9EPbWWtt+Jc1QDKf1pOOHmPfCvA=; b=XvqxsbbHrS+VVwxRyQFj1RcPBrVBMspcW2mfv1MmL7bc84KZ2Wf+xUudEP4UhwIbeFRrDV 6n+qYFoqMms8IzMyRTUCdKkUvHmS0iPFtRsvD7cqa0duA4DbNOJWyqca7X1PGILf+uhCby 22BbBB9jSnWlFUEsP5Ae1EBXNptoDt4= ARC-Authentication-Results: i=1; imf20.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=NUS6vtz6; spf=none (imf20.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1738921866; a=rsa-sha256; cv=none; b=63vzPpY6YN5OnBqKkqNd65+yeLp/ug2NtUGOqpdmlnFxTHCEi91uiObo/dnCIyYSCgBtob SB7mOmQjKiR/o706A4Rxr3nOAcEbq0BK19myusxoPoNoJ8c9kcf5Ybm2iW3epJQFuGnpqM uSn9cbpAoAXfRur9FfsUMnuaGo2lsvw= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=I3zHKIIrHLZPRQJg9EPbWWtt+Jc1QDKf1pOOHmPfCvA=; b=NUS6vtz6BBZ7OxDmYuLHAQtwWX HUruHEv4y0/38vsTBSGHox8V14WNq1koNkFg5pmNys8ITSq+N0vUPrbkypcit4YZVtWInswyqP0Tp dZNShe9iI9poWZp8S1lFD2iqYxG8P05Q4WcU38mSz4wcN5iD54UnOtpJRDPoVbZO8JlsK5ny+hMXH aP119/cCCAqI3efFIw+gCwSHgZYjQLlto0GwmQIHiZ8g11qIvGKim+94IMhBiMgh+R4Uupk5wAsDO 3rilYisiS29euEPQS4MgLYJbB2Suhr3H/IFCiZb8t7Ukex5srCcqcMhRL9m+9Gp7B4HRMMftRKvmk hGGKlz+w==; Received: from willy by casper.infradead.org with local (Exim 4.98 #2 (Red Hat Linux)) id 1tgL0h-00000007aqf-3vaR; Fri, 07 Feb 2025 09:50:55 +0000 Date: Fri, 7 Feb 2025 09:50:55 +0000 From: Matthew Wilcox 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, ying.huang@linux.alibaba.com, nphamcs@gmail.com, hannes@cmpxchg.org, feng.tang@intel.com, kbusch@meta.com, Hasan.Maruf@amd.com, sj@kernel.org, david@redhat.com, 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 Subject: Re: [LSF/MM/BPF TOPIC] Unifying sources of page temperature information - what info is actually wanted? Message-ID: References: <20250123105721.424117-1-raghavendra.kt@amd.com> <20250131122803.000031aa@huawei.com> <20250131130901.00000dd1@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Rspamd-Queue-Id: B5BFC1C000C X-Stat-Signature: a9qtxe5fc96qop1izd7iytehh66cgxxs X-Rspamd-Server: rspam03 X-HE-Tag: 1738921866-363543 X-HE-Meta: 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 IjzU/8dW NX+ZONGZHwb14zme6QGxjgIab19xkYxjM22SGG3UmrWwvx2yml7aOuZLpenGFwfuFNa1Oa7h0JXpJriy+EM8XyENbsMLqoY7oeuxq/Og5iaLts2wVHwIN06r3V5TXDi1iC2U5E99vHfSOWdCRKnylr1GClo/UwTMZhLuloCTyFLs87gbmxYnEvF/bLDEmAA0fmixkfeoNttnaYAxeGIfkL/nq5WaNrggCsY5e8l33gJYO9RD7OOII2OIViCtpc7HrZ1fm8KvP1DAGhpyIkW9F/g33zKuscKr3ac6+RbadbRMA3TpLZgIFtY5FjHKl2FBeOObJ46755QZEccPhpMVxopnAh9zBhByrcBn8 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000171, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, Feb 05, 2025 at 11:54:05AM +0530, Bharata B Rao wrote: > Here is a compilation of available temperature sources and how the > hot/access data is consumed by different subsystems: > > PA-Physical address available > VA-Virtual address available > AA-Access time available > NA-accessing Node info available > > I have left the slot blank for those which I am not sure about. > ================================================== > Temperature PA VA AA NA > source > ================================================== > PROT_NONE faults Y Y Y Y > -------------------------------------------------- > folio_mark_accessed() Y Y Y > -------------------------------------------------- > PTE A bit Y Y N N > -------------------------------------------------- > Platform hints Y Y Y Y > (AMD IBS) > -------------------------------------------------- > Device hints Y > (CXL HMU) > ================================================== > > And here is an attempt to compile how different subsystems > use the above data: > ============================================================== > Source Subsystem Consumption > ============================================================== > PROT_NONE faults NUMAB NUMAB=1 locality based > via process pgtable balancing > walk NUMAB=2 hot page > promotion > ============================================================== > folio_mark_accessed() FS/filemap/GUP LRU list activation > ============================================================== > PTE A bit via Reclaim:LRU LRU list activation, > rmap walk deactivation/demotion > ============================================================== > PTE A bit via Reclaim:MGLRU LRU list activation, > rmap walk and process deactivation/demotion > pgtable walk > ============================================================== > PTE A bit via DAMON LRU activation, > rmap walk hot page promotion, > demotion etc > ============================================================== > Platform hints NUMAB NUMAB=1 Locality based > (AMD IBS) balancing and > NUMAB=2 hot page > promotion > ============================================================== > Device hints NUMAB NUMAB=2 hot page > promotion > ============================================================== > The last two are listed as possibilities. > > Feel free to correct/clarify and add more. There's PG_young / PG_idle as well.