From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-f199.google.com (mail-qk0-f199.google.com [209.85.220.199]) by kanga.kvack.org (Postfix) with ESMTP id 9C6736B0024 for ; Tue, 27 Feb 2018 22:27:08 -0500 (EST) Received: by mail-qk0-f199.google.com with SMTP id 78so933361qky.17 for ; Tue, 27 Feb 2018 19:27:08 -0800 (PST) Received: from mx1.redhat.com (mx3-rdu2.redhat.com. [66.187.233.73]) by mx.google.com with ESMTPS id g23si816866qta.469.2018.02.27.19.27.07 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 27 Feb 2018 19:27:07 -0800 (PST) From: Baoquan He Subject: [PATCH v3 0/4] mm/sparse: Optimize memmap allocation during sparse_init() Date: Wed, 28 Feb 2018 11:26:53 +0800 Message-Id: <20180228032657.32385-1-bhe@redhat.com> Sender: owner-linux-mm@kvack.org List-ID: To: linux-kernel@vger.kernel.org, akpm@linux-foundation.org, dave.hansen@intel.com, pagupta@redhat.com Cc: linux-mm@kvack.org, kirill.shutemov@linux.intel.com, Baoquan He This is v3 post. V1 can be found here: https://www.spinics.net/lists/linux-mm/msg144486.html In sparse_init(), two temporary pointer arrays, usemap_map and map_map are allocated with the size of NR_MEM_SECTIONS. They are used to store each memory section's usemap and mem map if marked as present. In 5-level paging mode, this will cost 512M memory though they will be released at the end of sparse_init(). System with few memory, like kdump kernel which usually only has about 256M, will fail to boot because of allocation failure if CONFIG_X86_5LEVEL=y. In this patchset, optimize the memmap allocation code to only use usemap_map and map_map with the size of nr_present_sections. This makes kdump kernel boot up with normal crashkernel='' setting when CONFIG_X86_5LEVEL=y. Change log: v2->v3: Change nr_present_sections as __initdata and add code comment according to Andrew's suggestion. Change the local variable 'i' as idx_present which loops over the present sections, and improve the code. These are suggested by Dave and Pankaj. Add a new patch 0003 which adds a new parameter 'data_unit_size' to function alloc_usemap_and_memmap() in which we will update 'data' to make it point at new position. However its type 'void *' can't give us needed info to do that. Need pass the unit size in. So change code in patch 0004 accordingly. This is a code bug fix found when tested the memory deployed on multiple nodes. v1-v2: Split out the nr_present_sections adding as a single patch for easier reviewing. Rewrite patch log according to Dave's suggestion. Fix code bug in patch 0002 reported by test robot. Baoquan He (4): mm/sparse: Add a static variable nr_present_sections mm/sparsemem: Defer the ms->section_mem_map clearing mm/sparse: Add a new parameter 'data_unit_size' for alloc_usemap_and_memmap mm/sparse: Optimize memmap allocation during sparse_init() mm/sparse-vmemmap.c | 6 +++--- mm/sparse.c | 62 ++++++++++++++++++++++++++++++++++++++--------------- 2 files changed, 48 insertions(+), 20 deletions(-) -- 2.13.6 -- 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