From patchwork Tue Sep 24 18:30:51 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zhang Yanfei X-Patchwork-Id: 2935241 Return-Path: X-Original-To: patchwork-linux-acpi@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 95BAEBFF05 for ; Tue, 24 Sep 2013 18:31:41 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id E76D32042C for ; Tue, 24 Sep 2013 18:31:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9E5F02044C for ; Tue, 24 Sep 2013 18:31:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754658Ab3IXSbV (ORCPT ); Tue, 24 Sep 2013 14:31:21 -0400 Received: from mail-pd0-f175.google.com ([209.85.192.175]:58435 "EHLO mail-pd0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752933Ab3IXSbR (ORCPT ); Tue, 24 Sep 2013 14:31:17 -0400 Received: by mail-pd0-f175.google.com with SMTP id q10so4914242pdj.20 for ; Tue, 24 Sep 2013 11:31:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:content-type:content-transfer-encoding; bh=Wq0cJ0yq7vUgqJVNidcTLpOLYXqNCLx+DxF0luHSlUM=; b=t6SqvqjYckelwndpXG2IMJBEdHrCjcA5lu3XlUSSjewRCIsdt+ymYWNtBLVB58h9QR Tf2TL7Zg30FUp/Mq1IMKPcyyk2b0/u2UFewSRzYoYfm0XREYeM7WIlLt+5A6FfK26G7z iU+BImRN7+31Wejv3XCUm2FqgNe+VebtQYJ/KH9ZmdxN8OTHr47agOl9hTLJFvbOpoiG VABwCAUcPmKgA8CtOeIU2jJIyIqk5zIae8n1zxAi1tM0vzUPGeCwWyVk9vJt++EKTGRF KLL6BpcNJpCU/HZLGxk7MIJpe9N58Tai8X7FxgHRPcePt60wWQVu7gl5VZRFX4KadrTR ji7g== X-Received: by 10.66.27.143 with SMTP id t15mr6715021pag.171.1380047476267; Tue, 24 Sep 2013 11:31:16 -0700 (PDT) Received: from localhost.localdomain ([222.95.211.254]) by mx.google.com with ESMTPSA id pu5sm47388522pac.21.1969.12.31.16.00.00 (version=TLSv1 cipher=RC4-SHA bits=128/128); Tue, 24 Sep 2013 11:31:15 -0700 (PDT) Message-ID: <5241DA5B.8000909@gmail.com> Date: Wed, 25 Sep 2013 02:30:51 +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: "Rafael J . Wysocki" , lenb@kernel.org, Thomas Gleixner , mingo@elte.hu, "H. Peter Anvin" , Andrew Morton , Tejun Heo , 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 CC: "x86@kernel.org" , linux-doc@vger.kernel.org, "linux-kernel@vger.kernel.org" , Linux MM , linux-acpi@vger.kernel.org, imtangchen@gmail.com, Zhang Yanfei Subject: [PATCH v5 4/6] x86/mem-hotplug: Support initialize page tables in bottom-up References: <5241D897.1090905@gmail.com> In-Reply-To: <5241D897.1090905@gmail.com> Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org X-Spam-Status: No, score=-5.7 required=5.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED, FREEMAIL_FROM, KHOP_BIG_TO_CC, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, T_DKIM_INVALID, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Tang Chen The Linux kernel cannot migrate pages used by the kernel. As a result, kernel pages cannot be hot-removed. So we cannot allocate hotpluggable memory for the kernel. In a memory hotplug system, any numa node the kernel resides in should be unhotpluggable. And for a modern server, each node could have at least 16GB memory. So memory around the kernel image is highly likely unhotpluggable. ACPI SRAT (System Resource Affinity Table) contains the memory hotplug info. But before SRAT is parsed, memblock has already started to allocate memory for the kernel. So we need to prevent memblock from doing this. So direct memory mapping page tables setup is the case. init_mem_mapping() is called before SRAT is parsed. To prevent page tables being allocated within hotpluggable memory, we will use bottom-up direction to allocate page tables from the end of kernel image to the higher memory. Signed-off-by: Tang Chen Signed-off-by: Zhang Yanfei --- arch/x86/mm/init.c | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++- 1 files changed, 62 insertions(+), 2 deletions(-) diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c index dbe57e5..d35363e 100644 --- a/arch/x86/mm/init.c +++ b/arch/x86/mm/init.c @@ -456,6 +456,48 @@ static void __init memory_map_top_down(unsigned long map_start, init_range_memory_mapping(real_end, map_end); } +/** + * 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 bottom-up. + */ +static void __init memory_map_bottom_up(unsigned long map_start, + unsigned long map_end) +{ + unsigned long next, new_mapped_ram_size, start; + unsigned long mapped_ram_size = 0; + /* step_size need to be small so pgt_buf from BRK could cover it */ + unsigned long step_size = PMD_SIZE; + + start = map_start; + min_pfn_mapped = start >> PAGE_SHIFT; + + /* + * We start from the bottom (@map_start) and go to the top (@map_end). + * The memblock_find_in_range() gets us a block of RAM from the + * end of RAM in [min_pfn_mapped, max_pfn_mapped) used as new pages + * for page table. + */ + while (start < map_end) { + if (map_end - start > step_size) { + next = round_up(start + 1, step_size); + if (next > map_end) + next = map_end; + } else + next = map_end; + + new_mapped_ram_size = init_range_memory_mapping(start, next); + start = next; + + if (new_mapped_ram_size > mapped_ram_size) + step_size <<= STEP_SIZE_SHIFT; + mapped_ram_size += new_mapped_ram_size; + } +} + void __init init_mem_mapping(void) { unsigned long end; @@ -471,8 +513,26 @@ void __init init_mem_mapping(void) /* the ISA range is always mapped regardless of memory holes */ init_memory_mapping(0, ISA_END_ADDRESS); - /* setup direct mapping for range [ISA_END_ADDRESS, end) in top-down*/ - memory_map_top_down(ISA_END_ADDRESS, end); + /* + * If the allocation is in bottom-up direction, we setup direct mapping + * in bottom-up, otherwise we setup direct mapping in top-down. + */ + if (memblock_bottom_up()) { + unsigned long kernel_end; + + kernel_end = __pa_symbol(_end); + /* + * we need two separate calls here. This is because we want to + * allocate page tables above the kernel. So we first map + * [kernel_end, end) to make memory above the kernel be mapped + * as soon as possible. And then use page tables allocated above + * the kernel to map [ISA_END_ADDRESS, kernel_end). + */ + memory_map_bottom_up(kernel_end, end); + memory_map_bottom_up(ISA_END_ADDRESS, kernel_end); + } else { + memory_map_top_down(ISA_END_ADDRESS, end); + } #ifdef CONFIG_X86_64 if (max_pfn > max_low_pfn) {