From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt0-f197.google.com (mail-qt0-f197.google.com [209.85.216.197]) by kanga.kvack.org (Postfix) with ESMTP id 9CDD56B0296 for ; Thu, 22 Feb 2018 04:11:41 -0500 (EST) Received: by mail-qt0-f197.google.com with SMTP id y9so473167qtf.7 for ; Thu, 22 Feb 2018 01:11:41 -0800 (PST) Received: from mx1.redhat.com (mx3-rdu2.redhat.com. [66.187.233.73]) by mx.google.com with ESMTPS id x186si1924532qke.473.2018.02.22.01.11.40 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 22 Feb 2018 01:11:40 -0800 (PST) From: Baoquan He Subject: [PATCH v2 0/3] mm/sparse: Optimize memmap allocation during sparse_init() Date: Thu, 22 Feb 2018 17:11:27 +0800 Message-Id: <20180222091130.32165-1-bhe@redhat.com> Sender: owner-linux-mm@kvack.org List-ID: To: linux-kernel@vger.kernel.org, dave.hansen@intel.com Cc: linux-mm@kvack.org, akpm@linux-foundation.org, kirill.shutemov@linux.intel.com, mhocko@suse.com, tglx@linutronix.de, Baoquan He This is v2 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. Baoquan He (3): mm/sparse: Add a static variable nr_present_sections mm/sparsemem: Defer the ms->section_mem_map clearing mm/sparse: Optimize memmap allocation during sparse_init() mm/sparse-vmemmap.c | 9 +++++---- mm/sparse.c | 54 +++++++++++++++++++++++++++++++++++------------------ 2 files changed, 41 insertions(+), 22 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