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,URIBL_BLOCKED, USER_AGENT_MUTT autolearn=unavailable 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 E8257C282E3 for ; Thu, 25 Apr 2019 07:48:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AADFB218B0 for ; Thu, 25 Apr 2019 07:48:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556178524; bh=+Qgon2X3Xpjxac7EpKvxR+RQaesDw4jyLzgtHPOFurk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=kqQKVPt5LQwLE4BHOVIq2WwYsgh07S/vJdjfNVpvg7+daf21LN8hhJlpA6kbEfLMA G49ewclAK1IuCA/S7xD0km7KNo9r1cvCKrFlAr4EIbtorAX+2k7qul/k4wKZj0Z1cq PDWKyfJtcObz7rKrUOhfvoCzk8FrEa/xhU3vQNSA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727897AbfDYHsn (ORCPT ); Thu, 25 Apr 2019 03:48:43 -0400 Received: from mx2.suse.de ([195.135.220.15]:39600 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726184AbfDYHsn (ORCPT ); Thu, 25 Apr 2019 03:48:43 -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 23A2AAF60; Thu, 25 Apr 2019 07:48:42 +0000 (UTC) Date: Thu, 25 Apr 2019 09:48:41 +0200 From: Michal Hocko To: "Du, Fan" Cc: "akpm@linux-foundation.org" , "Wu, Fengguang" , "Williams, Dan J" , "Hansen, Dave" , "xishi.qiuxishi@alibaba-inc.com" , "Huang, Ying" , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" Subject: Re: [RFC PATCH 5/5] mm, page_alloc: Introduce ZONELIST_FALLBACK_SAME_TYPE fallback list Message-ID: <20190425074841.GN12751@dhcp22.suse.cz> References: <1556155295-77723-1-git-send-email-fan.du@intel.com> <1556155295-77723-6-git-send-email-fan.du@intel.com> <20190425063807.GK12751@dhcp22.suse.cz> <5A90DA2E42F8AE43BC4A093BF067884825785F04@SHSMSX104.ccr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5A90DA2E42F8AE43BC4A093BF067884825785F04@SHSMSX104.ccr.corp.intel.com> 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 Thu 25-04-19 07:43:09, Du, Fan wrote: > > > >-----Original Message----- > >From: Michal Hocko [mailto:mhocko@kernel.org] > >Sent: Thursday, April 25, 2019 2:38 PM > >To: Du, Fan > >Cc: akpm@linux-foundation.org; Wu, Fengguang ; > >Williams, Dan J ; Hansen, Dave > >; xishi.qiuxishi@alibaba-inc.com; Huang, Ying > >; linux-mm@kvack.org; linux-kernel@vger.kernel.org > >Subject: Re: [RFC PATCH 5/5] mm, page_alloc: Introduce > >ZONELIST_FALLBACK_SAME_TYPE fallback list > > > >On Thu 25-04-19 09:21:35, Fan Du wrote: > >> On system with heterogeneous memory, reasonable fall back lists woul be: > >> a. No fall back, stick to current running node. > >> b. Fall back to other nodes of the same type or different type > >> e.g. DRAM node 0 -> DRAM node 1 -> PMEM node 2 -> PMEM node 3 > >> c. Fall back to other nodes of the same type only. > >> e.g. DRAM node 0 -> DRAM node 1 > >> > >> a. is already in place, previous patch implement b. providing way to > >> satisfy memory request as best effort by default. And this patch of > >> writing build c. to fallback to the same node type when user specify > >> GFP_SAME_NODE_TYPE only. > > > >So an immediate question which should be answered by this changelog. Who > >is going to use the new gfp flag? Why cannot all allocations without an > >explicit numa policy fallback to all existing nodes? > > PMEM is good for frequently read accessed page, e.g. page cache(implicit page > request), or user space data base (explicit page request) > For now this patch create GFP_SAME_NODE_TYPE for such cases, additional > Implementation will be followed up. Then simply configure that NUMA node as movable and you get these allocations for any movable allocation. I am not really convinced a new gfp flag is really justified. -- Michal Hocko SUSE Labs