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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 A2379C10F14 for ; Tue, 16 Apr 2019 14:40:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7120520656 for ; Tue, 16 Apr 2019 14:40:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1555425603; bh=HDsa5qjoKP54tUlI0s82vGwRG/2PTcMuJjDbzVS2PmA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=pM7QP+2tK5kQ0zOYU3NmxAI7BFJz+SAltwuyR715kRDZ43tYK/iv0mBc/bMIqiAzj s7fh/GRRCvJ3HVhC/1JjHlbqXSLYHj9t+HIkutEcAdhW3DTqO+K/5M2cBS1qJsgTZo wKmobAlSfMMcU2JJqtsNsEf02K+U0W9gGNDWhYWs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729652AbfDPOkB (ORCPT ); Tue, 16 Apr 2019 10:40:01 -0400 Received: from mx2.suse.de ([195.135.220.15]:39840 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726605AbfDPOkB (ORCPT ); Tue, 16 Apr 2019 10:40:01 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 366E2AE56; Tue, 16 Apr 2019 14:40:00 +0000 (UTC) Date: Tue, 16 Apr 2019 16:39:58 +0200 From: Michal Hocko To: Dave Hansen Cc: Yang Shi , mgorman@techsingularity.net, riel@surriel.com, hannes@cmpxchg.org, akpm@linux-foundation.org, keith.busch@intel.com, dan.j.williams@intel.com, fengguang.wu@intel.com, fan.du@intel.com, ying.huang@intel.com, ziy@nvidia.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [v2 RFC PATCH 0/9] Another Approach to Use PMEM as NUMA Node Message-ID: <20190416143958.GI11561@dhcp22.suse.cz> References: <1554955019-29472-1-git-send-email-yang.shi@linux.alibaba.com> <20190412084702.GD13373@dhcp22.suse.cz> <20190416074714.GD11561@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue 16-04-19 07:30:20, Dave Hansen wrote: > On 4/16/19 12:47 AM, Michal Hocko wrote: > > You definitely have to follow policy. You cannot demote to a node which > > is outside of the cpuset/mempolicy because you are breaking contract > > expected by the userspace. That implies doing a rmap walk. > > What *is* the contract with userspace, anyway? :) > > Obviously, the preferred policy doesn't have any strict contract. > > The strict binding has a bit more of a contract, but it doesn't prevent > swapping. Yes, but swapping is not a problem for using binding for memory partitioning. > Strict binding also doesn't keep another app from moving the > memory. I would consider that a bug. -- Michal Hocko SUSE Labs