From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx168.postini.com [74.125.245.168]) by kanga.kvack.org (Postfix) with SMTP id 476BC6B0044 for ; Mon, 12 Aug 2013 17:12:19 -0400 (EDT) Message-ID: <52094F93.3010203@zytor.com> Date: Mon, 12 Aug 2013 14:11:47 -0700 From: "H. Peter Anvin" MIME-Version: 1.0 Subject: Re: [PATCH part5 0/7] Arrange hotpluggable memory as ZONE_MOVABLE. References: <1375956979-31877-1-git-send-email-tangchen@cn.fujitsu.com> <20130812145016.GI15892@htj.dyndns.org> <5208FBBC.2080304@zytor.com> <20130812152343.GK15892@htj.dyndns.org> <52090D7F.6060600@gmail.com> <20130812164650.GN15892@htj.dyndns.org> <52092811.3020105@gmail.com> <20130812202029.GB8288@mtj.dyndns.org> <3908561D78D1C84285E8C5FCA982C28F31CB74A1@ORSMSX106.amr.corp.intel.com> <20130812205456.GC8288@mtj.dyndns.org> <52094C30.7070204@zytor.com> In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Yinghai Lu Cc: Tejun Heo , "Luck, Tony" , Tang Chen , Tang Chen , "Moore, Robert" , "Zheng, Lv" , "rjw@sisk.pl" , "lenb@kernel.org" , "tglx@linutronix.de" , "mingo@elte.hu" , "akpm@linux-foundation.org" , "trenn@suse.de" , "jiang.liu@huawei.com" , "wency@cn.fujitsu.com" , "laijs@cn.fujitsu.com" , "isimatu.yasuaki@jp.fujitsu.com" , "izumi.taku@jp.fujitsu.com" , "mgorman@suse.de" , "minchan@kernel.org" , "mina86@mina86.com" , "gong.chen@linux.intel.com" , "vasilis.liaskovitis@profitbricks.com" , "lwoodman@redhat.com" , "riel@redhat.com" , "jweiner@redhat.com" , "prarit@redhat.com" , "zhangyanfei@cn.fujitsu.com" , "yanghy@cn.fujitsu.com" , "x86@kernel.org" , "linux-doc@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , "linux-acpi@vger.kernel.org" On 08/12/2013 02:06 PM, Yinghai Lu wrote: > > should use BRK for safe if the buffer is not too big. need bootloader > will have kernel run-time size range in same node ram. > The bootloader typically won't know. >> >> Again, how much memory are we talking about here? > > page tables, buffer for slit table, buffer for double > memblock.reserved, override acpi tables. > > looks like it is needing several mega bytes, esp someone using 4k page > mapping for debug purpose. > We need to set a careful limit, then. "Several megabytes" could be a problem causing a boot failure on a small memory machine if we extend the BRK too much... obviously, a too-small BRK can fail on large systems. -hpa -- 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