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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 19EF9C2BA83 for ; Thu, 13 Feb 2020 09:09:04 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id E5DE220848 for ; Thu, 13 Feb 2020 09:09:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E5DE220848 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 725AD6B0524; Thu, 13 Feb 2020 04:09:03 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 6D4E26B0525; Thu, 13 Feb 2020 04:09:03 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5C3DF6B0526; Thu, 13 Feb 2020 04:09:03 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0104.hostedemail.com [216.40.44.104]) by kanga.kvack.org (Postfix) with ESMTP id 41E7B6B0524 for ; Thu, 13 Feb 2020 04:09:03 -0500 (EST) Received: from smtpin11.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id DC3718248047 for ; Thu, 13 Feb 2020 09:09:02 +0000 (UTC) X-FDA: 76484529324.11.beds36_891e6002c470b X-HE-Tag: beds36_891e6002c470b X-Filterd-Recvd-Size: 2388 Received: from mga06.intel.com (mga06.intel.com [134.134.136.31]) by imf32.hostedemail.com (Postfix) with ESMTP for ; Thu, 13 Feb 2020 09:09:02 +0000 (UTC) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by orsmga104.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 13 Feb 2020 01:09:00 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,436,1574150400"; d="scan'208";a="227039215" Received: from yhuang-dev.sh.intel.com (HELO yhuang-dev) ([10.239.159.151]) by fmsmga007.fm.intel.com with ESMTP; 13 Feb 2020 01:08:59 -0800 From: "Huang\, Ying" To: , Subject: [LSF/MM/BPF TOPIC] AutoNUMA enhancements to optimize Tiered Memory CC: Dave Hansen , Dan Williams , Tim C Chen , Feng Tang Date: Thu, 13 Feb 2020 17:08:59 +0800 Message-ID: <87mu9mhn10.fsf@yhuang-dev.intel.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.001931, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Topic: AutoNUMA enhancements to optimize Tiered Memory Traditionally, all RAM is DRAM. Some DRAM might be closer/faster than others, but a byte of media has about the same cost whether it is close or far. But, with new memory tiers such as High-Bandwidth Memory or Persistent Memory, there is a choice between fast/expensive and slow/cheap. The existing reclaim mechanisms work wonderfully for moving cold data out of fast/expensive tiers. However, reclaim does not work well for moving hot data which might be stuck in a slow tier since the pages near the top of the LRU are the most recently accessed only if there=E2=80=99s regular memory pressure on the slow/cheap tiers. Fortunately, AutoNUMA *can* find recently-accessed pages regardless of memory pressure. We have repurposed it from being used for location-based optimization to being used for tier-based optimization. We have also optimized it for better hot data identification, such as to find frequently-accessed pages instead of recently-accessed pages, etc. We will show our findings so far, and discuss the remaining problems, potential solutions, and alternatives.