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 5A83EC433EF for ; Wed, 18 May 2022 19:51:18 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 986A56B0072; Wed, 18 May 2022 15:51:17 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 935DA6B0073; Wed, 18 May 2022 15:51:17 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 823DF6B0074; Wed, 18 May 2022 15:51:17 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 6F4266B0072 for ; Wed, 18 May 2022 15:51:17 -0400 (EDT) Received: from smtpin31.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 3561532CC3 for ; Wed, 18 May 2022 19:51:17 +0000 (UTC) X-FDA: 79479907794.31.63A5A9C Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by imf31.hostedemail.com (Postfix) with ESMTP id B3AC2200BC for ; Wed, 18 May 2022 19:50:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1652903475; x=1684439475; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=qI2hRvQWGqLlvCgm5r1r2wIsZFcii9ZgTyxajRKplqk=; b=AVM4TagKkdnRSMtZncTfQbz5wReh8nq3yaz4x+A1qvQib/o79I6BdATX v0vGcOUc7C44n+lgULIDK79HiP+odhJEmodTg01zt3yHJHimSIV7+qSma XkZ0OvaLw+hshn5M+ktS+6pC/cur8h5/WqtmC8zqtkyU6x0QIbkYyB0fA v7WfXtYxwKXivOFstfWKbUJRNmaN760Mq6/XJxBnGTl1aAAJoFxkoEO38 KaGKTl8nWIHXNyCH6lYhfwa6XcwdOaGtXs0j5ltRdspDxR2S1qSe44FcA LsQk2yB84zTzbdSfU3Xeq+6CE36vs36haU1WOEZ9XA+3f/+sJAsLxDAzc Q==; X-IronPort-AV: E=McAfee;i="6400,9594,10351"; a="271996181" X-IronPort-AV: E=Sophos;i="5.91,235,1647327600"; d="scan'208";a="271996181" Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 May 2022 12:51:12 -0700 X-IronPort-AV: E=Sophos;i="5.91,235,1647327600"; d="scan'208";a="817618883" Received: from kackerma-mobl2.amr.corp.intel.com (HELO [10.209.69.102]) ([10.209.69.102]) by fmsmga006-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 May 2022 12:51:11 -0700 Message-ID: Date: Wed, 18 May 2022 12:51:10 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.8.1 Subject: Re: [PATCH] Revert "mm/vmscan: never demote for memcg reclaim" Content-Language: en-US To: Johannes Weiner , Dave Hansen , "Huang, Ying" , Yang Shi , Andrew Morton Cc: linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com, Zi Yan , Michal Hocko , Shakeel Butt , Roman Gushchin References: <20220518190911.82400-1-hannes@cmpxchg.org> From: Dave Hansen In-Reply-To: <20220518190911.82400-1-hannes@cmpxchg.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Authentication-Results: imf31.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=AVM4TagK; spf=none (imf31.hostedemail.com: domain of dave.hansen@intel.com has no SPF policy when checking 192.55.52.115) smtp.mailfrom=dave.hansen@intel.com; dmarc=pass (policy=none) header.from=intel.com X-Rspam-User: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: B3AC2200BC X-Stat-Signature: uoo31ifr3sdpzn7p6f6et95wwj7mtmwo X-HE-Tag: 1652903446-90913 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 5/18/22 12:09, Johannes Weiner wrote: > However, with NUMA balancing now doing tier promotions, demotion is > part of the page aging process. Global reclaim demotes the coldest > toptier pages to secondary memory, where their life continues and from > which they have a chance to get promoted back. Essentially, tiered > memory systems have an LRU order that spans multiple nodes. Thanks for the detailed explanation. Ultimately, this was just intended as an optimization to make cgroup reclaim more efficient. But, I agree that ordering correctness should trump efficiency. Acked-by: Dave Hansen