Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753819Ab3IXNYR (ORCPT ); Tue, 24 Sep 2013 09:24:17 -0400 Received: from mail-pb0-f42.google.com ([209.85.160.42]:42601 "EHLO mail-pb0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751559Ab3IXNYP (ORCPT ); Tue, 24 Sep 2013 09:24:15 -0400 Message-ID: <52419264.3020409@gmail.com> Date: Tue, 24 Sep 2013 21:23:48 +0800 From: Zhang Yanfei User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:10.0.5) Gecko/20120607 Thunderbird/10.0.5 MIME-Version: 1.0 To: Tejun Heo CC: Zhang Yanfei , "Rafael J . Wysocki" , lenb@kernel.org, Thomas Gleixner , mingo@elte.hu, "H. Peter Anvin" , Andrew Morton , Toshi Kani , Wanpeng Li , Thomas Renninger , Yinghai Lu , Jiang Liu , Wen Congyang , Lai Jiangshan , isimatu.yasuaki@jp.fujitsu.com, izumi.taku@jp.fujitsu.com, Mel Gorman , Minchan Kim , mina86@mina86.com, gong.chen@linux.intel.com, vasilis.liaskovitis@profitbricks.com, lwoodman@redhat.com, Rik van Riel , jweiner@redhat.com, prarit@redhat.com, "x86@kernel.org" , linux-doc@vger.kernel.org, "linux-kernel@vger.kernel.org" , Linux MM , linux-acpi@vger.kernel.org, imtangchen@gmail.com Subject: Re: [PATCH 4/6] x86/mem-hotplug: Support initialize page tables bottom up References: <524162DA.30004@cn.fujitsu.com> <5241649B.3090302@cn.fujitsu.com> <20130924123340.GE2366@htj.dyndns.org> In-Reply-To: <20130924123340.GE2366@htj.dyndns.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2302 Lines: 70 On 09/24/2013 08:33 PM, Tejun Heo wrote: > Hello, > > On Tue, Sep 24, 2013 at 06:08:27PM +0800, Zhang Yanfei wrote: >> +#ifdef CONFIG_MOVABLE_NODE > > You don't need the above ifdef. The compiler will be able to cull the > code as long as memblock_bottom_up() is defined as constant > expression when !MOVABLE_NODE. yeah, will remove the #if. thanks. > >> +/** >> + * memory_map_bottom_up - Map [map_start, map_end) bottom up >> + * @map_start: start address of the target memory range >> + * @map_end: end address of the target memory range >> + * >> + * This function will setup direct mapping for memory range [map_start, map_end) >> + * in a heuristic way. In the beginning, step_size is small. The more memory we >> + * map memory in the next loop. > > The same comment as before. Now we have two function with the > identical comment but behaving differently, which isn't nice. OK, will change them. > > ... >> + * If the allocation is in bottom-up direction, we start from the >> + * bottom and go to the top: first [kernel_end, end) and then >> + * [ISA_END_ADDRESS, kernel_end). Otherwise, we start from the top >> + * (end of memory) and go to the bottom. >> + * >> + * The memblock_find_in_range() gets us a block of RAM in >> + * [min_pfn_mapped, max_pfn_mapped) used as new pages for page table. >> */ >> - memory_map_top_down(ISA_END_ADDRESS, end); >> + if (memblock_bottom_up()) { >> + unsigned long kernel_end; >> + >> + kernel_end = round_up(__pa_symbol(_end), PMD_SIZE); >> + memory_map_bottom_up(kernel_end, end); >> + memory_map_bottom_up(ISA_END_ADDRESS, kernel_end); > > Hmm... so, this is kinda weird. We're doing it in two chunks and > mapping memory between ISA_END_ADDRESS and kernel_end right on top of > ISA_END_ADDRESS? Can't you give enough information to the mapping > function so that it can map everything on top of kernel_end in single > go? You mean we should call memory_map_bottom_up like this: memory_map_bottom_up(ISA_END_ADDRESS, end) right? > > Thanks. > -- Thanks. Zhang Yanfei -- 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/