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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 4137AF36B9B for ; Fri, 10 Apr 2026 01:14:55 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 6A9016B0005; Thu, 9 Apr 2026 21:14:54 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 65A116B0089; Thu, 9 Apr 2026 21:14:54 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5487B6B008A; Thu, 9 Apr 2026 21:14:54 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 4111C6B0005 for ; Thu, 9 Apr 2026 21:14:54 -0400 (EDT) Received: from smtpin01.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id D3750160331 for ; Fri, 10 Apr 2026 01:14:53 +0000 (UTC) X-FDA: 84640876866.01.6EACD18 Received: from mail-pj1-f47.google.com (mail-pj1-f47.google.com [209.85.216.47]) by imf01.hostedemail.com (Postfix) with ESMTP id 1C71C40003 for ; Fri, 10 Apr 2026 01:14:51 +0000 (UTC) Authentication-Results: imf01.hostedemail.com; dkim=pass header.d=gmail.com header.s=20251104 header.b=jeMhll+L; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf01.hostedemail.com: domain of ritesh.list@gmail.com designates 209.85.216.47 as permitted sender) smtp.mailfrom=ritesh.list@gmail.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1775783692; a=rsa-sha256; cv=none; b=mYE2aQppkA0ZlCc7r69u+MNxpM+6vD6OnpbQu2oqxPlxmyMkFO6wGARvb9QkDKADyAJ7Nh jL8Xwx05xG/T+8lm7B/Hp+ypEP2H9qCZcbTaPPCFCpVPrkPTb117ZxpI5Mv2tNQtz5nR5z Gh+wSpjwePAjF7uUhGLlblPjuzT47to= ARC-Authentication-Results: i=1; imf01.hostedemail.com; dkim=pass header.d=gmail.com header.s=20251104 header.b=jeMhll+L; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf01.hostedemail.com: domain of ritesh.list@gmail.com designates 209.85.216.47 as permitted sender) smtp.mailfrom=ritesh.list@gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1775783692; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references:dkim-signature; bh=iPuNz30W1kc7kVkvLSskv85UK2fp6q3cCfYgHn1vLws=; b=pNTK2KhGSrTJAB4coeFxdeCqX90dQkzGQINQTXJL1V97qw0yInOQb2JwOl6vE8ShtG59f3 oeydzLqO+f3lHZQ7y7hEaFf6bKPHTEeF13zMyIpdO/dcwXorQ9Y7iSIOkVRDFwVNF7S+Mu IhF507C5nHzYDOcwHjPzY9+exFP6MAM= Received: by mail-pj1-f47.google.com with SMTP id 98e67ed59e1d1-356337f058aso1126243a91.2 for ; Thu, 09 Apr 2026 18:14:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1775783691; x=1776388491; darn=kvack.org; h=references:message-id:date:in-reply-to:subject:cc:to:from:from:to :cc:subject:date:message-id:reply-to; bh=iPuNz30W1kc7kVkvLSskv85UK2fp6q3cCfYgHn1vLws=; b=jeMhll+Lb4Vfror1QUKloIh9MtODSqAa39MBrwOeYmkKVLPNPZcreSaJ11NfvYv5Rp pjXvhkNHj9bXCxPxtWLDSgoUVw9wmp68swNPFiqpTRlvqt7+av+Prp7HOKLJPJWa0nQV sv5hpubxNRqCLBxtNye23XfQGDe7/lDRmquEtK3yFyPrkoeekZrgUsq+7x1YkEcD3mj4 VUFUqtenegVjvTifzQiNz+jWRnSqb2r8BJMgD9jhlZCSaYk2exDoSDpLtKsi/3qWndxT sh1Lx/Ra5cyEl5WkLBhltaY3V2IuMr8LsK3lK2VLIk/8afEmmoRHtaDzh2G+aYX2LJan PTAA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1775783691; x=1776388491; h=references:message-id:date:in-reply-to:subject:cc:to:from:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=iPuNz30W1kc7kVkvLSskv85UK2fp6q3cCfYgHn1vLws=; b=Qg4C3g/4tWHrZ4prTZ47wLVujQYVAEfetm4iUoK1t8P9QMQ1ZQLRk6OepxsvTrkfE3 5+KJvkZLly9ooPQPPdsMmRHb+sJ+2CCgkIsoH8RggUVupWtsjFBKkMK+hKfV17b3amhh zLjdkG/WeiYY2pFilHo/lcgf0vlbYCiKmTieClZRFUXcreIhkwrVOD1TDdSsrz0yxjL3 ZBCTVN4EmT3SA4DA8djSvIwTePVlv2+WyByF8MQMnh3iJ7nmBrky2eKA71fyiqZ7k5R/ QBbiFfmVO+qVEKTOFggVbcoQTMnRI/YGB9l2hyv5palMwRggP+cKAjFi1wuZdHnOJE3X D/TQ== X-Forwarded-Encrypted: i=1; AJvYcCU1MclgXgKjMlJtUXogjSmJP7AlJmkd5gCFl7uTLwX+uLFbh5i4q5EOQDZLj3dDbLj4BhKHlIblxg==@kvack.org X-Gm-Message-State: AOJu0Yy8KQRds9y6SDzIDk5Su6RDM+ASzCQUYVWoVsbycEdB0o4f5xBq 2/espoefb88neci37XuLAHMLY1P3mY7oxCcI0FqYmgrQzKRUrX2pBElj X-Gm-Gg: AeBDieuGGwP2qXtRboC/cQBfnOOOZpvtqtgHiiRDSPfEe9v1oJbGkhiFCcWDJRXJB1j zFTXnkF42iw9/N15wjXAZeoRGsZqvJcMWg+UrLeM7aOdh5h4T4ODlc8vYa+IVg5RK0eooJFjlIq q3TCuElgDHOXtcTlPz/yZwyoGN/5Ag4euFTJrhw8b+0jU1X3NtzW20PJSBtIewrgmKHfgk8XdSI iW31qTpqvnFc3/3RuL9BCwIBdB6Eu7gE4vdar6FQF+8+nDnkF0oP82aeVhHN5vD2WciTrfPVMlW jfHu+M7UKlnvA7OxJeVXFdl3x3E3fpM/k6xrNXQNH3AAUFfgIPCjzGp584W1OuJg4L4kb+V4TgG 2wupBgZFj83LIB9Zq/e+efWGY0btGy5+5onICVbVz9eF+Ct36UllOqVDHuseKRbZZy56NZN2hH3 XLOeb8xc5cp+LWKI+XJ/88Iw== X-Received: by 2002:a17:90b:17d2:b0:35b:928e:ae67 with SMTP id 98e67ed59e1d1-35e42857f46mr1220745a91.26.1775783690658; Thu, 09 Apr 2026 18:14:50 -0700 (PDT) Received: from pve-server ([49.205.216.49]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-35e3515b404sm4611574a91.15.2026.04.09.18.14.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 09 Apr 2026 18:14:49 -0700 (PDT) From: Ritesh Harjani (IBM) To: Gregory Price Cc: "Huang, Ying" , Donet Tom , David Hildenbrand , Andrew Morton , Ingo Molnar , Peter Zijlstra , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Baolin Wang , Ying Huang , Juri Lelli , Mel Gorman Subject: Re: [PATCH v2] memory tiering: Do not allow promotion if NUMA_BALANCING_MEMORY_TIERING is disabled In-Reply-To: Date: Fri, 10 Apr 2026 06:37:08 +0530 Message-ID: References: <20260323094849.3903-1-donettom@linux.ibm.com> <87wlyqt52m.fsf@DESKTOP-5N7EMDA> <87o6k1ubg4.fsf@DESKTOP-5N7EMDA> <877bqgvs4k.fsf@DESKTOP-5N7EMDA> X-Stat-Signature: zd18kqso41toa3fhrqjesi4gkhzu3ity X-Rspamd-Queue-Id: 1C71C40003 X-Rspam-User: X-Rspamd-Server: rspam03 X-HE-Tag: 1775783691-312421 X-HE-Meta: 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 3VkU8k1C 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Gregory Price writes: > On Thu, Apr 09, 2026 at 09:12:56AM +0530, Ritesh Harjani wrote: >> "Huang, Ying" writes: >> >> >>>>> Donet Tom writes: >> >> >> >> >> >> Thanks for the clarification. I was running some experiments where I >> >> only required migration, not promotion. However, I observed that >> >> promotion was still occurring even when NUMA_BALANCING_MEMORY_TIERING >> >> was disabled, which led me to believe it might be a bug, so I reported >> >> it. >> >> >> >> As I understand it, enabling both NUMA_BALANCING_MEMORY_TIERING and >> >> NUMA_BALANCING_NORMAL results in both promotion and migration. Given >> >> this, do you see any concerns with modifying the behavior of >> >> NUMA_BALANCING_NORMAL? >> >> >> >> With this patch, we would have better control over enabling and >> >> disabling promotion independently. I would appreciate your thoughts on >> >> this. >> > >> > IIUC, we change the existing user visible behavior only with strong >> > enough practical reason. >> >> So what I understood from this discussion so far is, we don't have any >> mechanism to do auto-numa base page migration between DRAM -to- DRAM w/o >> triggering promotions too from a lower tiers to higher tiers. >> >> ... This to me sounds more like a broken interface. >> > > It only seems that way because the naming suggests tiering did not exist > prior to _TIERING - instead _NORMAL just operates in a suboptimal manner > when multiple tiers exist. > > _NORMAL migrates a page when it detects the node it's on is not the > local node of the task doing the work. > > _TIERING takes into account the liveliness of the pages with a > timestamp. > Sure Gregory and Ying, got the point. Thanks for your comments and feedback. Appreciate it! For now let's live with that, in case if we come across a real world usecase where we would want, only-migration w/o tiering behavior, then will share it. -ritesh