Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757200Ab2K3KTy (ORCPT ); Fri, 30 Nov 2012 05:19:54 -0500 Received: from mx2.parallels.com ([64.131.90.16]:34305 "EHLO mx2.parallels.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757049Ab2K3KTw (ORCPT ); Fri, 30 Nov 2012 05:19:52 -0500 Message-ID: <50B88835.80805@parallels.com> Date: Fri, 30 Nov 2012 14:19:33 +0400 From: Glauber Costa User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/17.0 Thunderbird/17.0 MIME-Version: 1.0 To: "Luck, Tony" CC: Mel Gorman , "H. Peter Anvin" , Jiang Liu , Tang Chen , "akpm@linux-foundation.org" , "rob@landley.net" , "isimatu.yasuaki@jp.fujitsu.com" , "laijs@cn.fujitsu.com" , "wency@cn.fujitsu.com" , "linfeng@cn.fujitsu.com" , "yinghai@kernel.org" , "kosaki.motohiro@jp.fujitsu.com" , "minchan.kim@gmail.com" , "rientjes@google.com" , "rusty@rustcorp.com.au" , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , "linux-doc@vger.kernel.org" , Len Brown , "Wang, Frank" Subject: Re: [PATCH v2 0/5] Add movablecore_map boot option References: <1353667445-7593-1-git-send-email-tangchen@cn.fujitsu.com> <50B5CFAE.80103@huawei.com> <3908561D78D1C84285E8C5FCA982C28F1C95EDCE@ORSMSX108.amr.corp.intel.com> <50B68467.5020008@zytor.com> <20121129110045.GX8218@suse.de> <3908561D78D1C84285E8C5FCA982C28F1C95FF53@ORSMSX108.amr.corp.intel.com> In-Reply-To: <3908561D78D1C84285E8C5FCA982C28F1C95FF53@ORSMSX108.amr.corp.intel.com> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1388 Lines: 27 On 11/30/2012 06:58 AM, Luck, Tony wrote: >> If any significant percentage of memory is in ZONE_MOVABLE then the memory >> hotplug people will have to deal with all the lowmem/highmem problems >> that used to be faced by 32-bit x86 with PAE enabled. > > While these problems may still exist on large systems - I think it becomes > harder to construct workloads that run into problems. In those bad old days > a significant fraction of lowmem was consumed by the kernel ... so it was > pretty easy to find meta-data intensive workloads that would push it over > a cliff. Here we are talking about systems with say 128GB per node divided > into 64GB moveable and 64GB non-moveable (and I'd regard this as a rather > low-end machine). Unless the workload consists of zillions of tiny processes > all mapping shared memory blocks, the percentage of memory allocated to > the kernel is going to be tiny compared with the old 4GB days. > Which is a perfectly common workload for containers, where you can have hundreds of machines (per node) being sold out to third parties, a lot of them consuming every single bit of metadata they can. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/