From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f200.google.com (mail-pf0-f200.google.com [209.85.192.200]) by kanga.kvack.org (Postfix) with ESMTP id 9DE7C6B0253 for ; Wed, 1 Feb 2017 01:46:28 -0500 (EST) Received: by mail-pf0-f200.google.com with SMTP id e4so404305453pfg.4 for ; Tue, 31 Jan 2017 22:46:28 -0800 (PST) Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com. [148.163.158.5]) by mx.google.com with ESMTPS id n5si13546769pgh.185.2017.01.31.22.46.27 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 31 Jan 2017 22:46:27 -0800 (PST) Received: from pps.filterd (m0098420.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.20/8.16.0.20) with SMTP id v116i0DQ109366 for ; Wed, 1 Feb 2017 01:46:27 -0500 Received: from e28smtp07.in.ibm.com (e28smtp07.in.ibm.com [125.16.236.7]) by mx0b-001b2d01.pphosted.com with ESMTP id 28bank82gh-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Wed, 01 Feb 2017 01:46:26 -0500 Received: from localhost by e28smtp07.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 1 Feb 2017 12:16:23 +0530 Received: from d28relay06.in.ibm.com (d28relay06.in.ibm.com [9.184.220.150]) by d28dlp03.in.ibm.com (Postfix) with ESMTP id 52BBA125801F for ; Wed, 1 Feb 2017 12:18:07 +0530 (IST) Received: from d28av07.in.ibm.com (d28av07.in.ibm.com [9.184.220.146]) by d28relay06.in.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id v116kL6g23396404 for ; Wed, 1 Feb 2017 12:16:21 +0530 Received: from d28av07.in.ibm.com (localhost [127.0.0.1]) by d28av07.in.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id v116kKcV022166 for ; Wed, 1 Feb 2017 12:16:20 +0530 Subject: Re: [RFC V2 03/12] mm: Change generic FALLBACK zonelist creation process References: <20170130033602.12275-1-khandual@linux.vnet.ibm.com> <20170130033602.12275-4-khandual@linux.vnet.ibm.com> <07bd439c-6270-b219-227b-4079d36a2788@intel.com> <434aa74c-e917-490e-85ab-8c67b1a82d95@linux.vnet.ibm.com> <79bfd849-8e6c-2f6d-0acf-4256a4137526@nvidia.com> From: Anshuman Khandual Date: Wed, 1 Feb 2017 12:16:16 +0530 MIME-Version: 1.0 In-Reply-To: <79bfd849-8e6c-2f6d-0acf-4256a4137526@nvidia.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Message-Id: Sender: owner-linux-mm@kvack.org List-ID: To: John Hubbard , Dave Hansen , Anshuman Khandual , linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: mhocko@suse.com, vbabka@suse.cz, mgorman@suse.de, minchan@kernel.org, aneesh.kumar@linux.vnet.ibm.com, bsingharora@gmail.com, srikar@linux.vnet.ibm.com, haren@linux.vnet.ibm.com, jglisse@redhat.com, dan.j.williams@intel.com On 01/31/2017 12:55 PM, John Hubbard wrote: > On 01/30/2017 05:57 PM, Dave Hansen wrote: >> On 01/30/2017 05:36 PM, Anshuman Khandual wrote: >>>> Let's say we had a CDM node with 100x more RAM than the rest of the >>>> system and it was just as fast as the rest of the RAM. Would we still >>>> want it isolated like this? Or would we want a different policy? >>> >>> But then the other argument being, dont we want to keep this 100X more >>> memory isolated for some special purpose to be utilized by specific >>> applications ? >> >> I was thinking that in this case, we wouldn't even want to bother with >> having "system RAM" in the fallback lists. A device who got its memory >> usage off by 1% could start to starve the rest of the system. A sane >> policy in this case might be to isolate the "system RAM" from the >> device's. > > I also don't like having these policies hard-coded, and your 100x > example above helps clarify what can go wrong about it. It would be > nicer if, instead, we could better express the "distance" between nodes > (bandwidth, latency, relative to sysmem, perhaps), and let the NUMA > system figure out the Right Thing To Do. > > I realize that this is not quite possible with NUMA just yet, but I > wonder if that's a reasonable direction to go with this? That is complete overhaul of the NUMA representation in the kernel. What CDM attempts is to find a solution with existing NUMA framework and with as little code change as possible. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org