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 E29A0C43334 for ; Wed, 8 Jun 2022 08:25:39 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 8857C8D0017; Wed, 8 Jun 2022 04:25:39 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 80E4D8D0009; Wed, 8 Jun 2022 04:25:39 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6B0088D0017; Wed, 8 Jun 2022 04:25:39 -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 560EA8D0009 for ; Wed, 8 Jun 2022 04:25:39 -0400 (EDT) Received: from smtpin06.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id CA8A9E94 for ; Wed, 8 Jun 2022 08:25:38 +0000 (UTC) X-FDA: 79554384756.06.BC59047 Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by imf28.hostedemail.com (Postfix) with ESMTP id B00A4C006B for ; Wed, 8 Jun 2022 08:25:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1654676737; x=1686212737; h=message-id:subject:from:to:cc:date:in-reply-to: references:mime-version:content-transfer-encoding; bh=ExKBbSfCOtpswNsSsOMGnKwgFVvsSYdnSKk9OuhGdxo=; b=Ac7OrTd77sSuNpDS/B42VQdJrjh0WYdUTo6ddScFMRm7SioU0FangSWT cNbqSXiqvIqcGU3qlGAqElwtm1YYQUq9U3HcrDt2EPLZsT8qpgn9oAn5H 5gG1Tt8rt8Mudx7CmG4zlSWB0HX7QtoezKcaViyoP0gzGndfCKJjlJwBG CKjFfQ1fAi1tMGxklIas/23fiAoS5lcR02pFS/tZbxfh+hdXDlDMNCN/B p5d+O6D+kXuoz327husMNvfHPDlOnVW8dS8LVZXgs1303tqRLpX5Kwxfb pomdZrwLQkkvdoBThLddddypJIApiLKHnmzIQUZMEekFVK1u5u9X2fzI6 w==; X-IronPort-AV: E=McAfee;i="6400,9594,10371"; a="265625573" X-IronPort-AV: E=Sophos;i="5.91,285,1647327600"; d="scan'208";a="265625573" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Jun 2022 01:24:02 -0700 X-IronPort-AV: E=Sophos;i="5.91,285,1647327600"; d="scan'208";a="636671615" Received: from xding11-mobl.ccr.corp.intel.com ([10.254.214.239]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Jun 2022 01:23:57 -0700 Message-ID: <06d04b6588b43ca010ec78ce0dee8127193f5562.camel@intel.com> Subject: Re: [PATCH v5 6/9] mm/demotion: Add support for removing node from demotion memory tiers From: Ying Huang To: Aneesh Kumar K V , linux-mm@kvack.org, akpm@linux-foundation.org Cc: Wei Xu , Greg Thelen , Yang Shi , Davidlohr Bueso , Tim C Chen , Brice Goglin , Michal Hocko , Linux Kernel Mailing List , Hesham Almatary , Dave Hansen , Jonathan Cameron , Alistair Popple , Dan Williams , Feng Tang , Jagdish Gediya , Baolin Wang , David Rientjes Date: Wed, 08 Jun 2022 16:23:55 +0800 In-Reply-To: <81956d2e-0bfe-78ba-5ad0-f6c388c2190e@linux.ibm.com> References: <20220603134237.131362-1-aneesh.kumar@linux.ibm.com> <20220603134237.131362-7-aneesh.kumar@linux.ibm.com> <81956d2e-0bfe-78ba-5ad0-f6c388c2190e@linux.ibm.com> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.38.3-1 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Stat-Signature: rimixdkkstgwz4fgdtt98d7w8nz6tr8j X-Rspam-User: Authentication-Results: imf28.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=Ac7OrTd7; spf=none (imf28.hostedemail.com: domain of ying.huang@intel.com has no SPF policy when checking 134.134.136.20) smtp.mailfrom=ying.huang@intel.com; dmarc=pass (policy=none) header.from=intel.com X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: B00A4C006B X-HE-Tag: 1654676737-210488 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, 2022-06-08 at 13:50 +0530, Aneesh Kumar K V wrote: > On 6/8/22 12:29 PM, Ying Huang wrote: > > On Fri, 2022-06-03 at 19:12 +0530, Aneesh Kumar K.V wrote: > > > This patch adds the special string "none" as a supported memtier value > > > that we can use to remove a specific node from being using as demotion target. > > > > > > For ex: > > > :/sys/devices/system/node/node1# cat memtier > > > 1 > > > :/sys/devices/system/node/node1# cat ../../memtier/memtier1/nodelist > > > 1-3 > > > :/sys/devices/system/node/node1# echo none > memtier > > > :/sys/devices/system/node/node1# > > > :/sys/devices/system/node/node1# cat memtier > > > :/sys/devices/system/node/node1# cat ../../memtier/memtier1/nodelist > > > 2-3 > > > :/sys/devices/system/node/node1# > > > > Do you have a practical use case for this? What kind of memory node > > needs to be removed from memory tiers demotion/promotion? > > > > This came up in our internal discussion. It was mentioned that there is > a need to skip some slow memory nodes from participating in demotion. Again, can you provide a practical use case? Why we shouldn't demote cold pages to these slow memory nodes? How do we use these slow memory node? These slow memory node is slower than disk? Best Regards, Huang, Ying