From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx161.postini.com [74.125.245.161]) by kanga.kvack.org (Postfix) with SMTP id 2D31E6B003A for ; Mon, 12 Aug 2013 17:11:11 -0400 (EDT) From: "Luck, Tony" Subject: RE: [PATCH part5 0/7] Arrange hotpluggable memory as ZONE_MOVABLE. Date: Mon, 12 Aug 2013 21:11:06 +0000 Message-ID: <3908561D78D1C84285E8C5FCA982C28F31CB7552@ORSMSX106.amr.corp.intel.com> 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> In-Reply-To: <20130812205456.GC8288@mtj.dyndns.org> Content-Language: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: owner-linux-mm@kvack.org List-ID: To: Tejun Heo Cc: Tang Chen , "H. Peter Anvin" , 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" , "yinghai@kernel.org" , "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" >> The only fly I see in the ointment here is the crazy fragmentation of ph= ysical >> memory below 4G on X86 systems. Typically it will all be on the same no= de. >> But I don't know if there is any specification that requires it be that = way. If some >> "helpful" OEM decided to make some "lowmem" (below 4G) be available on >> every node, they might in theory do something truly awesomely strange. = But >> even here - the granularity of such mappings tends to be large enough th= at >> the "allocate near where the kernel was loaded" should still work to mak= e those >> allocations be on the same node for the "few megabytes" level of allocat= ions. > > Yeah, "near kernel" allocations are needed only till SRAT information > is parsed and fed into memblock. From then on, it'll be the usual > node-affine top-down allocations, so the memory amount of interest > here is inherently tiny; otherwise, we're doing something silly in our > boot sequence. Just an idle, slightly related, question. Will a 64-bit X86 kernel work if= the physical load address is >4GB? That would get it away from the fragmented bits of address space and into vast tracts of same-node-ness. -Tony -- 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