From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C0D751A23A9 for ; Fri, 7 Feb 2025 09:51:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738921882; cv=none; b=RLXXg4FIbPpuZmW49YBwPEF/5YqyMJsTbg7Bj9txDUTvJ3VzNnScCjhfQtT0z5WQ+bcgBOTqHy1zs9ad7qdXgjAeeghyYTG0TGGN6vHd4A9uBOo/vgSBST/1wlqlxVlJkAqPZz33jdxtC+YsV03njNoy0pP02OeT1BDbwTdsHd0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738921882; c=relaxed/simple; bh=ngJO7QmaDQrn23uZgS2xweCgDp91dFI3t0Q8eN71yoQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=SNPaqm++SXRveEuoB04YTMCIAN5MsDWtDzHksX86L9UcW2DtXhTIDg/Z6KoVf4VT1QBxWAwGt2HQ/bAHoKsNt+egQvPMmNXijEM+/Z4nedVoLV4orMOLyVHQTTpe+SpwsomMSOzLaMYC57bvnzbhhJBLGQ/qUd4Nc4iI2dMwX7w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=NUS6vtz6; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="NUS6vtz6" 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> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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.