From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx144.postini.com [74.125.245.144]) by kanga.kvack.org (Postfix) with SMTP id 207156B0031 for ; Wed, 24 Jul 2013 22:10:41 -0400 (EDT) Message-ID: <51F089C1.4010402@cn.fujitsu.com> Date: Thu, 25 Jul 2013 10:13:21 +0800 From: Tang Chen MIME-Version: 1.0 Subject: Re: [PATCH 14/21] x86, acpi, numa: Reserve hotpluggable memory at early time. References: <1374220774-29974-1-git-send-email-tangchen@cn.fujitsu.com> <1374220774-29974-15-git-send-email-tangchen@cn.fujitsu.com> <20130723205557.GS21100@mtj.dyndns.org> <20130723213212.GA21100@mtj.dyndns.org> In-Reply-To: <20130723213212.GA21100@mtj.dyndns.org> Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=ISO-8859-1; format=flowed Sender: owner-linux-mm@kvack.org List-ID: To: Tejun Heo Cc: tglx@linutronix.de, mingo@elte.hu, hpa@zytor.com, 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 On 07/24/2013 05:32 AM, Tejun Heo wrote: > On Tue, Jul 23, 2013 at 04:55:57PM -0400, Tejun Heo wrote: >> On Fri, Jul 19, 2013 at 03:59:27PM +0800, Tang Chen wrote: >>> + /* >>> + * In such an early time, we don't have nid. We specify pxm >>> + * instead of MAX_NUMNODES to prevent memblock merging regions >>> + * on different nodes. And later modify pxm to nid when nid is >>> + * mapped so that we can arrange ZONE_MOVABLE on different >>> + * nodes. >>> + */ >>> + memblock_reserve_hotpluggable(base_address, length, pxm); >> >> This is rather hacky. Why not just introduce MEMBLOCK_NO_MERGE flag? The original thinking is to merge regions with the same nid. So I used pxm. And then refresh the nid field when nids are mapped. I will try to introduce MEMBLOCK_NO_MERGE and make it less hacky. > > Also, if memblock is gonna know about hotplug memory, why not just let > it control its allocation too instead of blocking it by reserving it > from outside? These are all pretty general memory hotplug logic which > doesn't have much to do with acpi and I think too much is implemented > on the acpi side. At the very beginning, a long time ago, we just did this. Please refer to: https://lkml.org/lkml/2012/12/10/656 In order to let memblock control the allocation, we have to store the hotpluggable ranges somewhere, and keep the allocated range out of the hotpluggable regions. I just think reserving the hotpluggable regions and then memblock won't allocate them. No need to do any other limitation. And also, the acpi side modification in this patch-set is to get SRAT and parse it. I think most of the logic in acpi_reserve_hotpluggable_memory() is necessary. I don't think letting memblock control the allocation will make the acpi side easier. Thanks. -- 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