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 X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DDDB9C11D00 for ; Thu, 20 Feb 2020 22:16:06 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id A8DE020801 for ; Thu, 20 Feb 2020 22:16:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A8DE020801 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 3D5366B0005; Thu, 20 Feb 2020 17:16:06 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 386456B0006; Thu, 20 Feb 2020 17:16:06 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 275256B0007; Thu, 20 Feb 2020 17:16:06 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0084.hostedemail.com [216.40.44.84]) by kanga.kvack.org (Postfix) with ESMTP id 108826B0005 for ; Thu, 20 Feb 2020 17:16:06 -0500 (EST) Received: from smtpin02.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id BE4204DB2 for ; Thu, 20 Feb 2020 22:16:05 +0000 (UTC) X-FDA: 76511914290.02.badge43_8c6e3d9f61e42 X-HE-Tag: badge43_8c6e3d9f61e42 X-Filterd-Recvd-Size: 6021 Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by imf21.hostedemail.com (Postfix) with ESMTP for ; Thu, 20 Feb 2020 22:16:04 +0000 (UTC) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga102.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 20 Feb 2020 14:16:03 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,465,1574150400"; d="scan'208";a="240154150" Received: from schen9-desk.jf.intel.com (HELO [10.54.74.162]) ([10.54.74.162]) by orsmga006.jf.intel.com with ESMTP; 20 Feb 2020 14:16:02 -0800 To: Michal Hocko , "Kirill A. Shutemov" Cc: lsf-pc@lists.linux-foundation.org, linux-mm@kvack.org, Dave Hansen , Dan Williams , Huang Ying References: <20200214104541.GT31689@dhcp22.suse.cz> <20200220160604.ak33n3hrqouyiuyv@box> <20200220161915.GI20509@dhcp22.suse.cz> From: Tim Chen Autocrypt: addr=tim.c.chen@linux.intel.com; prefer-encrypt=mutual; keydata= mQINBE6ONugBEAC1c8laQ2QrezbYFetwrzD0v8rOqanj5X1jkySQr3hm/rqVcDJudcfdSMv0 BNCCjt2dofFxVfRL0G8eQR4qoSgzDGDzoFva3NjTJ/34TlK9MMouLY7X5x3sXdZtrV4zhKGv 3Rt2osfARdH3QDoTUHujhQxlcPk7cwjTXe4o3aHIFbcIBUmxhqPaz3AMfdCqbhd7uWe9MAZX 7M9vk6PboyO4PgZRAs5lWRoD4ZfROtSViX49KEkO7BDClacVsODITpiaWtZVDxkYUX/D9OxG AkxmqrCxZxxZHDQos1SnS08aKD0QITm/LWQtwx1y0P4GGMXRlIAQE4rK69BDvzSaLB45ppOw AO7kw8aR3eu/sW8p016dx34bUFFTwbILJFvazpvRImdjmZGcTcvRd8QgmhNV5INyGwtfA8sn L4V13aZNZA9eWd+iuB8qZfoFiyAeHNWzLX/Moi8hB7LxFuEGnvbxYByRS83jsxjH2Bd49bTi XOsAY/YyGj6gl8KkjSbKOkj0IRy28nLisFdGBvgeQrvaLaA06VexptmrLjp1Qtyesw6zIJeP oHUImJltjPjFvyfkuIPfVIB87kukpB78bhSRA5mC365LsLRl+nrX7SauEo8b7MX0qbW9pg0f wsiyCCK0ioTTm4IWL2wiDB7PeiJSsViBORNKoxA093B42BWFJQARAQABtDRUaW0gQ2hlbiAo d29yayByZWxhdGVkKSA8dGltLmMuY2hlbkBsaW51eC5pbnRlbC5jb20+iQI+BBMBAgAoAhsD BgsJCAcDAgYVCAIJCgsEFgIDAQIeAQIXgAUCXFIuxAUJEYZe0wAKCRCiZ7WKota4STH3EACW 1jBRzdzEd5QeTQWrTtB0Dxs5cC8/P7gEYlYQCr3Dod8fG7UcPbY7wlZXc3vr7+A47/bSTVc0 DhUAUwJT+VBMIpKdYUbvfjmgicL9mOYW73/PHTO38BsMyoeOtuZlyoUl3yoxWmIqD4S1xV04 q5qKyTakghFa+1ZlGTAIqjIzixY0E6309spVTHoImJTkXNdDQSF0AxjW0YNejt52rkGXXSoi IgYLRb3mLJE/k1KziYtXbkgQRYssty3n731prN5XrupcS4AiZIQl6+uG7nN2DGn9ozy2dgTi smPAOFH7PKJwj8UU8HUYtX24mQA6LKRNmOgB290PvrIy89FsBot/xKT2kpSlk20Ftmke7KCa 65br/ExDzfaBKLynztcF8o72DXuJ4nS2IxfT/Zmkekvvx/s9R4kyPyebJ5IA/CH2Ez6kXIP+ q0QVS25WF21vOtK52buUgt4SeRbqSpTZc8bpBBpWQcmeJqleo19WzITojpt0JvdVNC/1H7mF 4l7og76MYSTCqIKcLzvKFeJSie50PM3IOPp4U2czSrmZURlTO0o1TRAa7Z5v/j8KxtSJKTgD lYKhR0MTIaNw3z5LPWCCYCmYfcwCsIa2vd3aZr3/Ao31ZnBuF4K2LCkZR7RQgLu+y5Tr8P7c e82t/AhTZrzQowzP0Vl6NQo8N6C2fcwjSrkCDQROjjboARAAx+LxKhznLH0RFvuBEGTcntrC 3S0tpYmVsuWbdWr2ZL9VqZmXh6UWb0K7w7OpPNW1FiaWtVLnG1nuMmBJhE5jpYsi+yU8sbMA 5BEiQn2hUo0k5eww5/oiyNI9H7vql9h628JhYd9T1CcDMghTNOKfCPNGzQ8Js33cFnszqL4I N9jh+qdg5FnMHs/+oBNtlvNjD1dQdM6gm8WLhFttXNPn7nRUPuLQxTqbuoPgoTmxUxR3/M5A KDjntKEdYZziBYfQJkvfLJdnRZnuHvXhO2EU1/7bAhdz7nULZktw9j1Sp9zRYfKRnQdIvXXa jHkOn3N41n0zjoKV1J1KpAH3UcVfOmnTj+u6iVMW5dkxLo07CddJDaayXtCBSmmd90OG0Odx cq9VaIu/DOQJ8OZU3JORiuuq40jlFsF1fy7nZSvQFsJlSmHkb+cDMZDc1yk0ko65girmNjMF hsAdVYfVsqS1TJrnengBgbPgesYO5eY0Tm3+0pa07EkONsxnzyWJDn4fh/eA6IEUo2JrOrex O6cRBNv9dwrUfJbMgzFeKdoyq/Zwe9QmdStkFpoh9036iWsj6Nt58NhXP8WDHOfBg9o86z9O VMZMC2Q0r6pGm7L0yHmPiixrxWdW0dGKvTHu/DH/ORUrjBYYeMsCc4jWoUt4Xq49LX98KDGN dhkZDGwKnAUAEQEAAYkCJQQYAQIADwIbDAUCXFIulQUJEYZenwAKCRCiZ7WKota4SYqUEACj P/GMnWbaG6s4TPM5Dg6lkiSjFLWWJi74m34I19vaX2CAJDxPXoTU6ya8KwNgXU4yhVq7TMId keQGTIw/fnCv3RLNRcTAapLarxwDPRzzq2snkZKIeNh+WcwilFjTpTRASRMRy9ehKYMq6Zh7 PXXULzxblhF60dsvi7CuRsyiYprJg0h2iZVJbCIjhumCrsLnZ531SbZpnWz6OJM9Y16+HILp iZ77miSE87+xNa5Ye1W1ASRNnTd9ftWoTgLezi0/MeZVQ4Qz2Shk0MIOu56UxBb0asIaOgRj B5RGfDpbHfjy3Ja5WBDWgUQGgLd2b5B6MVruiFjpYK5WwDGPsj0nAOoENByJ+Oa6vvP2Olkl gQzSV2zm9vjgWeWx9H+X0eq40U+ounxTLJYNoJLK3jSkguwdXOfL2/Bvj2IyU35EOC5sgO6h VRt3kA/JPvZK+6MDxXmm6R8OyohR8uM/9NCb9aDw/DnLEWcFPHfzzFFn0idp7zD5SNgAXHzV PFY6UGIm86OuPZuSG31R0AU5zvcmWCeIvhxl5ZNfmZtv5h8TgmfGAgF4PSD0x/Bq4qobcfaL ugWG5FwiybPzu2H9ZLGoaRwRmCnzblJG0pRzNaC/F+0hNf63F1iSXzIlncHZ3By15bnt5QDk l50q2K/r651xphs7CGEdKi1nU0YJVbQxJQ== Subject: Re: [Lsf-pc] [LSF/MM TOPIC] Memory cgroups, whether you like it or not Message-ID: <36e127fe-814e-9b22-cb7d-73a2e3daf2aa@linux.intel.com> Date: Thu, 20 Feb 2020 14:16:02 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.2 MIME-Version: 1.0 In-Reply-To: <20200220161915.GI20509@dhcp22.suse.cz> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable 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 2/20/20 8:19 AM, Michal Hocko wrote: >> >> Michal, could you remind what the deal with soft limit? Why is it dead= ? >=20 > because of the very disruptive semantic. Essentially the way how it was > grafted into the normal reclaim. It is essentially a priority 0 reclaim > round to shrink a hierarchy which is the most in excess before we do a > normal reclaim. This can lead to an over reclaim, long stalls etc. Thanks for the explanation. I wonder if a few factors could mitigate the stalls in the tiered memory context: 1. The speed of demotion between top tier memory and second tier memory is much faster than reclaiming the pages and swapping them out. 2. Demotion targets pages that are colder and less active. 3. If we engage the page demotion mostly in the background, say via kswap= d, and not in the direct reclaim path, we can avoid long stalls during page allocation. If the memory pressure is severe on the top tier memory, perhaps the memory could be allocated from the se= cond tier memory node to avoid stalling. The stalls could still prove to be problematic. We're implementing prototypes and we'll have a better ideas on workload latencies once we ca= n collect data. Tim