Received: by 2002:a25:5b86:0:0:0:0:0 with SMTP id p128csp947068ybb; Thu, 28 Mar 2019 15:45:42 -0700 (PDT) X-Google-Smtp-Source: APXvYqxSwIOtGdk1QWUiX+aw1sX6eRSyKkK2nJmdYEN804pX4Qb6GkDLHsWs37CXV2d9rk6QfosK X-Received: by 2002:a62:3244:: with SMTP id y65mr12333256pfy.255.1553813142743; Thu, 28 Mar 2019 15:45:42 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1553813142; cv=none; d=google.com; s=arc-20160816; b=RsfLH61F5K4ioRxIuVnIuVNblb2K020P2idCDg6kmIT/YmzdOXVK3V6tVRbCF5cqGN 7gDDflLMSROYkdwvTEmSAwMxCNgNDF8+siCOCjRXqu+JlMA+JIPLC3AKoQwkk/8M54gK HQQNLRdlpBMcfcC5YIooKE0M3wegJ0ZGVx90WYr0uoKBgIXimOGfPYrevudSOwbj3ymd ycuwz/Wbn9CwkwQZLbz7P0WWPUsAs1piOe+QPcdYezmxdueih72lIYO1m9UweGmb9xgv LVN+ClTWvLQ+KNEeVWigZDoc3ZDDiZlv6+aS340f9Wv8+wWhyW7pKnYgxetXLT7cMC82 Z3mw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:user-agent:in-reply-to :content-disposition:mime-version:references:message-id:subject:cc :to:from:date; bh=hoXTOMqs77/aDHAbNEOXTowKIcFUiYOGUIvRdh/SNQo=; b=sgqC9AgHazbvDudTAx+LPhzMYyuou5vVGc5gK4i8Fy9sOPDq7z5zkgj2sf/Ot281DQ 99hPhuIAgln+y2+xhw08TCHR1BQA3Nf2GOQkfT8SN4ezHj0nVWRtncEX1mUk/nEbbLte X2EKyoZi1Kf8gilZI2DGxVLmNfPNwDSE9kF0fsA8z89ZS3FlODdT3js29YwfR0mv/9bi g8ewikHtS3SZX2DZYtFbVulO9unFrLsqzFbs0Bv9Id+0CWDZXPE5TSG1AKmsXkn/h/vH +7i4wTkQgaEq5Z/3GDVlb/3+QuIBl2uKiKH6DiZMok3K6lZ/mago7DpnmP7W4NXim8Ic l0aA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id e2si285345pgv.511.2019.03.28.15.45.26; Thu, 28 Mar 2019 15:45:42 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728038AbfC1Woh (ORCPT + 99 others); Thu, 28 Mar 2019 18:44:37 -0400 Received: from mga14.intel.com ([192.55.52.115]:22048 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727238AbfC1Woh (ORCPT ); Thu, 28 Mar 2019 18:44:37 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 28 Mar 2019 15:44:36 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.60,282,1549958400"; d="scan'208";a="126781810" Received: from unknown (HELO localhost.localdomain) ([10.232.112.69]) by orsmga007.jf.intel.com with ESMTP; 28 Mar 2019 15:44:35 -0700 Date: Thu, 28 Mar 2019 16:45:50 -0600 From: Keith Busch To: Yang Shi Cc: "mhocko@suse.com" , "mgorman@techsingularity.net" , "riel@surriel.com" , "hannes@cmpxchg.org" , "akpm@linux-foundation.org" , "Hansen, Dave" , "Busch, Keith" , "Williams, Dan J" , "Wu, Fengguang" , "Du, Fan" , "Huang, Ying" , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH 06/10] mm: vmscan: demote anon DRAM pages to PMEM node Message-ID: <20190328224549.GA11100@localhost.localdomain> References: <1553316275-21985-1-git-send-email-yang.shi@linux.alibaba.com> <1553316275-21985-7-git-send-email-yang.shi@linux.alibaba.com> <20190324222040.GE31194@localhost.localdomain> <20190327003541.GE4328@localhost.localdomain> <39d8fb56-df60-9382-9b47-59081d823c3c@linux.alibaba.com> <20190327130822.GD7389@localhost.localdomain> <599849e6-05b6-1e4d-7578-5cf8825963d2@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <599849e6-05b6-1e4d-7578-5cf8825963d2@linux.alibaba.com> User-Agent: Mutt/1.9.1 (2017-09-22) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 28, 2019 at 02:59:30PM -0700, Yang Shi wrote: > Yes, it still could fail. I can't tell which way is better for now. I > just thought scanning another round then migrating should be still > faster than swapping off the top of my head. I think it depends on the relative capacities between your primary and migration tiers and how it's used. Applications may allocate and pin directly out of pmem if they wish, so it's not a dedicated fallback memory space like swap.