From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f54.google.com (mail-pa0-f54.google.com [209.85.220.54]) by kanga.kvack.org (Postfix) with ESMTP id 928B16B0031 for ; Wed, 2 Jul 2014 02:48:53 -0400 (EDT) Received: by mail-pa0-f54.google.com with SMTP id et14so12060126pad.27 for ; Tue, 01 Jul 2014 23:48:53 -0700 (PDT) Received: from szxga01-in.huawei.com (szxga01-in.huawei.com. [119.145.14.64]) by mx.google.com with ESMTPS id aw13si29383027pac.24.2014.07.01.23.48.50 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Tue, 01 Jul 2014 23:48:52 -0700 (PDT) Message-ID: <53B3AB3B.1050809@huawei.com> Date: Wed, 2 Jul 2014 14:48:27 +0800 From: Zhang Zhen MIME-Version: 1.0 Subject: Re: How to boot up an ARM board enabled CONFIG_SPARSEMEM References: <53B26229.5030504@huawei.com> <53B26364.1040606@huawei.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: Linux MM , wangnan0@huawei.com On 2014/7/2 2:45, Yinghai Lu wrote: > On Tue, Jul 1, 2014 at 12:29 AM, Zhang Zhen wrote: >> Hi, >> >> Recently We are testing stable kernel 3.10 on an ARM board. >> It failed to boot if we enabled CONFIG_SPARSEMEM config. > > Arm support 2 sockets and numa now? > ARM doesn't support numa until now. We have added memory hotplug feature on ARM arch. So we need to enable CONFIG_SPARSEMEM. >> 1. In mem_init() and show_mem() compare pfn instead of page just like the patch in attachement. >> 2. Enable CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER when enabled CONFIG_SPARSEMEM. >> >> QUESTION: >> >> I want to know why CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER depends on x86_64 ? > > That make memory allocation have less memory hole, from old bootmem bitmap > allocation stage. > > Maybe we don't need that anymore as we have memblock allocation that is more > smarter with alignment handling. > > Also allocating big size and use them block by block, could save some time on > searching on allocation function when memblock have lots of entries on > memory/reserved arrays. > > Thanks > > Yinghai > Hi, Yinghai Have you seen my patch ? If we enabled CONFIG_SPARSEMEM here in the patch need to enable CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER to guarantee the pages of different sections are continuous. So in my opinion, CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER doesn't need to depend on x86_64, which helps futher coding. If i'm wrong, please let me know ! Thanks for your comments! > -- 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