From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752092AbeDFLGo (ORCPT ); Fri, 6 Apr 2018 07:06:44 -0400 Received: from mail-wm0-f67.google.com ([74.125.82.67]:36532 "EHLO mail-wm0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751492AbeDFLGn (ORCPT ); Fri, 6 Apr 2018 07:06:43 -0400 X-Google-Smtp-Source: AIpwx4+VuJxI26EkjlIMJ3tbLNDDxn/m55DfWh1BgIQ563w7iwX4RT4Os8W0u/+WD0F/L43d6igFxw== Date: Fri, 6 Apr 2018 14:05:57 +0300 From: "Kirill A. Shutemov" To: Andrew Morton , dave.hansen@intel.com Cc: Baoquan He , linux-kernel@vger.kernel.org, pagupta@redhat.com, linux-mm@kvack.org, kirill.shutemov@linux.intel.com Subject: Re: [PATCH v3 0/4] mm/sparse: Optimize memmap allocation during sparse_init() Message-ID: <20180406110557.xg2edtjgzmsdksry@node.shutemov.name> References: <20180228032657.32385-1-bhe@redhat.com> <20180405150842.350e4febc06a813138f00416@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180405150842.350e4febc06a813138f00416@linux-foundation.org> User-Agent: NeoMutt/20180223 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 05, 2018 at 03:08:42PM -0700, Andrew Morton wrote: > On Wed, 28 Feb 2018 11:26:53 +0800 Baoquan He wrote: > > > 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. > > This patchset could do with some more review, please? I don't really understand sparsemem good enough to comment on the patchset. Dave, could you review this? -- Kirill A. Shutemov