Received: by 2002:a05:6a10:206:0:0:0:0 with SMTP id 6csp981934pxj; Thu, 27 May 2021 16:57:25 -0700 (PDT) X-Google-Smtp-Source: ABdhPJxgBXZOV5PIyb1yOxVM2QQR5hK28EufsAPdQrubgIcH07WMFj0S2Wc0eTmzakyfBgxo8yu5 X-Received: by 2002:a05:6402:2681:: with SMTP id w1mr6918240edd.223.1622159845605; Thu, 27 May 2021 16:57:25 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1622159845; cv=none; d=google.com; s=arc-20160816; b=gEYDsgwWwTM8lQtyxzypwfDOtWpsREBG6Lr4pH++x82Zw3mIBTlzme4I0vT8waVH7f BzOB21IocyhjANw8IAZQKt1rXBuM+ceO0dDmnD+Cxhrhbv6M+TuAPvB7EENTw1mBEIF+ zb+om7lU+xYO7wboRGSIvJxxL4FjAR7t2JIur4spK6tBIoWVVCEoN859zSstp+Bvcwo9 96dGZG+VKkUD84BTazAyoNXM1YmKcejtAtMI5LR+6T5JDaGhFjja8NfvYvRvDKH6GpS8 B13AWqM42pj1HulFyXNDu4kZIFI9z/hg6ZX5LupSMW7lZxIpYStpYqQhis0SZQP1E02A fVlA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:content-language :in-reply-to:mime-version:user-agent:date:message-id:autocrypt:from :references:cc:to:subject:ironport-sdr:ironport-sdr; bh=bqwx9/wEjMAUukOnb6vkxwYL8oSQcIYPO1r+Kf5jd1E=; b=ZeNqtnHk920F8hxE/7Ulh+fskqytWoxb9Ag81lsx3WG+6tRY5wAKhu9GJTHxKIvVZ0 +b7rg6M77dvsVNpYC+iUt7UiMgI9xOqojWx2thoKjg+1P6088fh5/T/yQX1NQmfiCrxE JJWhmKeDalf3Jp6MMz9UMPR4O5+/RpwHy5gD3cFC3i0CFxF5eUUdD6Gpdi/+DrZcLcKQ 7q+oeE3wJdVQGhpqMHhlAEi4xlN8MQEJ9PFi/qtHiCd4bZ8IIUyz2L57L3FVEj1kQttj yGcru7iAgcDgqFo0WiFnTk2D2enHWats+xxR+ayJ0wQ7xT88/Q/i0nkb5CR9Q2EVXCRR 9IZw== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=intel.com Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id g2si3051523edu.441.2021.05.27.16.57.03; Thu, 27 May 2021 16:57:25 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=intel.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235365AbhE0TiA (ORCPT + 99 others); Thu, 27 May 2021 15:38:00 -0400 Received: from mga12.intel.com ([192.55.52.136]:4167 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234187AbhE0Th6 (ORCPT ); Thu, 27 May 2021 15:37:58 -0400 IronPort-SDR: 345uYSbRy8QlE/1/r9uuY3/SHHZmluF3/u2CsCzww05ZtA4JsO/qJjfWjKnjObmes+uOp0AE2I xvhqDcz606XA== X-IronPort-AV: E=McAfee;i="6200,9189,9997"; a="182476009" X-IronPort-AV: E=Sophos;i="5.83,228,1616482800"; d="scan'208";a="182476009" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 May 2021 12:36:24 -0700 IronPort-SDR: tr9HPIJDUJ0IO0vxXlGe01y5nvxI6D2qHeB3tLJ8LTr8SGXywXcoYvxlLcmZvJgvkcDSCyuMBe 8GvQfqsHFNOw== X-IronPort-AV: E=Sophos;i="5.83,228,1616482800"; d="scan'208";a="445162832" Received: from sushilsu-mobl1.amr.corp.intel.com (HELO [10.209.3.242]) ([10.209.3.242]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 May 2021 12:36:23 -0700 Subject: Re: [PATCH 0/6 v2] Calculate pcp->high based on zone sizes and active CPUs To: Mel Gorman , Andrew Morton Cc: Hillf Danton , Dave Hansen , Vlastimil Babka , Michal Hocko , LKML , Linux-MM , "Tang, Feng" References: <20210525080119.5455-1-mgorman@techsingularity.net> From: Dave Hansen Autocrypt: addr=dave.hansen@intel.com; keydata= xsFNBE6HMP0BEADIMA3XYkQfF3dwHlj58Yjsc4E5y5G67cfbt8dvaUq2fx1lR0K9h1bOI6fC oAiUXvGAOxPDsB/P6UEOISPpLl5IuYsSwAeZGkdQ5g6m1xq7AlDJQZddhr/1DC/nMVa/2BoY 2UnKuZuSBu7lgOE193+7Uks3416N2hTkyKUSNkduyoZ9F5twiBhxPJwPtn/wnch6n5RsoXsb ygOEDxLEsSk/7eyFycjE+btUtAWZtx+HseyaGfqkZK0Z9bT1lsaHecmB203xShwCPT49Blxz VOab8668QpaEOdLGhtvrVYVK7x4skyT3nGWcgDCl5/Vp3TWA4K+IofwvXzX2ON/Mj7aQwf5W iC+3nWC7q0uxKwwsddJ0Nu+dpA/UORQWa1NiAftEoSpk5+nUUi0WE+5DRm0H+TXKBWMGNCFn c6+EKg5zQaa8KqymHcOrSXNPmzJuXvDQ8uj2J8XuzCZfK4uy1+YdIr0yyEMI7mdh4KX50LO1 pmowEqDh7dLShTOif/7UtQYrzYq9cPnjU2ZW4qd5Qz2joSGTG9eCXLz5PRe5SqHxv6ljk8mb ApNuY7bOXO/A7T2j5RwXIlcmssqIjBcxsRRoIbpCwWWGjkYjzYCjgsNFL6rt4OL11OUF37wL QcTl7fbCGv53KfKPdYD5hcbguLKi/aCccJK18ZwNjFhqr4MliQARAQABzShEYXZpZCBDaHJp c3RvcGhlciBIYW5zZW4gPGRhdmVAc3I3MS5uZXQ+wsF7BBMBAgAlAhsDBgsJCAcDAgYVCAIJ CgsEFgIDAQIeAQIXgAUCTo3k0QIZAQAKCRBoNZUwcMmSsMO2D/421Xg8pimb9mPzM5N7khT0 2MCnaGssU1T59YPE25kYdx2HntwdO0JA27Wn9xx5zYijOe6B21ufrvsyv42auCO85+oFJWfE K2R/IpLle09GDx5tcEmMAHX6KSxpHmGuJmUPibHVbfep2aCh9lKaDqQR07gXXWK5/yU1Dx0r VVFRaHTasp9fZ9AmY4K9/BSA3VkQ8v3OrxNty3OdsrmTTzO91YszpdbjjEFZK53zXy6tUD2d e1i0kBBS6NLAAsqEtneplz88T/v7MpLmpY30N9gQU3QyRC50jJ7LU9RazMjUQY1WohVsR56d ORqFxS8ChhyJs7BI34vQusYHDTp6PnZHUppb9WIzjeWlC7Jc8lSBDlEWodmqQQgp5+6AfhTD kDv1a+W5+ncq+Uo63WHRiCPuyt4di4/0zo28RVcjtzlGBZtmz2EIC3vUfmoZbO/Gn6EKbYAn rzz3iU/JWV8DwQ+sZSGu0HmvYMt6t5SmqWQo/hyHtA7uF5Wxtu1lCgolSQw4t49ZuOyOnQi5 f8R3nE7lpVCSF1TT+h8kMvFPv3VG7KunyjHr3sEptYxQs4VRxqeirSuyBv1TyxT+LdTm6j4a mulOWf+YtFRAgIYyyN5YOepDEBv4LUM8Tz98lZiNMlFyRMNrsLV6Pv6SxhrMxbT6TNVS5D+6 UorTLotDZKp5+M7BTQRUY85qARAAsgMW71BIXRgxjYNCYQ3Xs8k3TfAvQRbHccky50h99TUY sqdULbsb3KhmY29raw1bgmyM0a4DGS1YKN7qazCDsdQlxIJp9t2YYdBKXVRzPCCsfWe1dK/q 66UVhRPP8EGZ4CmFYuPTxqGY+dGRInxCeap/xzbKdvmPm01Iw3YFjAE4PQ4hTMr/H76KoDbD cq62U50oKC83ca/PRRh2QqEqACvIH4BR7jueAZSPEDnzwxvVgzyeuhwqHY05QRK/wsKuhq7s UuYtmN92Fasbxbw2tbVLZfoidklikvZAmotg0dwcFTjSRGEg0Gr3p/xBzJWNavFZZ95Rj7Et db0lCt0HDSY5q4GMR+SrFbH+jzUY/ZqfGdZCBqo0cdPPp58krVgtIGR+ja2Mkva6ah94/oQN lnCOw3udS+Eb/aRcM6detZr7XOngvxsWolBrhwTQFT9D2NH6ryAuvKd6yyAFt3/e7r+HHtkU kOy27D7IpjngqP+b4EumELI/NxPgIqT69PQmo9IZaI/oRaKorYnDaZrMXViqDrFdD37XELwQ gmLoSm2VfbOYY7fap/AhPOgOYOSqg3/Nxcapv71yoBzRRxOc4FxmZ65mn+q3rEM27yRztBW9 AnCKIc66T2i92HqXCw6AgoBJRjBkI3QnEkPgohQkZdAb8o9WGVKpfmZKbYBo4pEAEQEAAcLB XwQYAQIACQUCVGPOagIbDAAKCRBoNZUwcMmSsJeCEACCh7P/aaOLKWQxcnw47p4phIVR6pVL e4IEdR7Jf7ZL00s3vKSNT+nRqdl1ugJx9Ymsp8kXKMk9GSfmZpuMQB9c6io1qZc6nW/3TtvK pNGz7KPPtaDzvKA4S5tfrWPnDr7n15AU5vsIZvgMjU42gkbemkjJwP0B1RkifIK60yQqAAlT YZ14P0dIPdIPIlfEPiAWcg5BtLQU4Wg3cNQdpWrCJ1E3m/RIlXy/2Y3YOVVohfSy+4kvvYU3 lXUdPb04UPw4VWwjcVZPg7cgR7Izion61bGHqVqURgSALt2yvHl7cr68NYoFkzbNsGsye9ft M9ozM23JSgMkRylPSXTeh5JIK9pz2+etco3AfLCKtaRVysjvpysukmWMTrx8QnI5Nn5MOlJj 1Ov4/50JY9pXzgIDVSrgy6LYSMc4vKZ3QfCY7ipLRORyalFDF3j5AGCMRENJjHPD6O7bl3Xo 4DzMID+8eucbXxKiNEbs21IqBZbbKdY1GkcEGTE7AnkA3Y6YB7I/j9mQ3hCgm5muJuhM/2Fr OPsw5tV/LmQ5GXH0JQ/TZXWygyRFyyI2FqNTx4WHqUn3yFj8rwTAU1tluRUYyeLy0ayUlKBH ybj0N71vWO936MqP6haFERzuPAIpxj2ezwu0xb1GjTk4ynna6h5GjnKgdfOWoRtoWndMZxbA z5cecg== Message-ID: <7177f59b-dc05-daff-7dc6-5815b539a790@intel.com> Date: Thu, 27 May 2021 12:36:21 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20210525080119.5455-1-mgorman@techsingularity.net> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Mel, Feng Tang tossed these on a "Cascade Lake" system with 96 threads and ~512G of persistent memory and 128G of DRAM. The PMEM is in "volatile use" mode and being managed via the buddy just like the normal RAM. The PMEM zones are big ones: present 65011712 = 248 G high 134595 = 525 M The PMEM nodes, of course, don't have any CPUs in them. With your series, the pcp->high value per-cpu is 69584 pages or about 270MB per CPU. Scaled up by the 96 CPU threads, that's ~26GB of worst-case memory in the pcps per zone, or roughly 10% of the size of the zone. I did see quite a few pcp->counts above 60,000, so it's definitely possible in practice to see the pcps filled up. This was not observed to cause any actual problems in practice. But, it's still a bit worrisome. Maybe instead of pretending that cpu-less nodes have one cpu: nr_local_cpus = max(1U, cpumask_weight(cpumask_of_node(zone_to_nid(zone)))); we should just consider them to have *all* the CPUs in the system. Perhaps: nr_local_cpus = cpumask_weight(cpumask_of_node(zone_to_nid(zone))); if (!nr_local_cpus) nr_local_cpus = num_online_cpus(); Even if a system has a silly number of CPUs, the 'high' sizes will still hit a floor at 4*batch: high = max(high, batch << 2); Which doesn't seem too bad, especially considering that CPU-less nodes naturally have less contention.