From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753121AbdHNLnb (ORCPT ); Mon, 14 Aug 2017 07:43:31 -0400 Received: from mx2.suse.de ([195.135.220.15]:55947 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752475AbdHNLna (ORCPT ); Mon, 14 Aug 2017 07:43:30 -0400 Date: Mon, 14 Aug 2017 13:43:26 +0200 From: Michal Hocko To: Pasha Tatashin Cc: linux-kernel@vger.kernel.org, sparclinux@vger.kernel.org, linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-arm-kernel@lists.infradead.org, x86@kernel.org, kasan-dev@googlegroups.com, borntraeger@de.ibm.com, heiko.carstens@de.ibm.com, davem@davemloft.net, willy@infradead.org, ard.biesheuvel@linaro.org, will.deacon@arm.com, catalin.marinas@arm.com, sam@ravnborg.org Subject: Re: [v6 02/15] x86/mm: setting fields in deferred pages Message-ID: <20170814114326.GH19063@dhcp22.suse.cz> References: <1502138329-123460-1-git-send-email-pasha.tatashin@oracle.com> <1502138329-123460-3-git-send-email-pasha.tatashin@oracle.com> <20170811090214.GD30811@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri 11-08-17 11:39:41, Pasha Tatashin wrote: > >AFAIU register_page_bootmem_info_node is only about struct pages backing > >pgdat, usemap and memmap. Those should be in reserved memblocks and we > >do not initialize those at later times, they are not relevant to the > >deferred initialization as your changelog suggests so the ordering with > >get_page_bootmem shouldn't matter. Or am I missing something here? > > The pages for pgdata, usemap, and memmap are part of reserved, and thus > getting initialized when free_all_bootmem() is called. > > So, we have something like this in mem_init() > > register_page_bootmem_info > register_page_bootmem_info_node > get_page_bootmem > .. setting fields here .. > such as: page->freelist = (void *)type; > > free_all_bootmem() > free_low_memory_core_early() > for_each_reserved_mem_region() > reserve_bootmem_region() > init_reserved_page() <- Only if this is deferred reserved page > __init_single_pfn() > __init_single_page() > memset(0) <-- Loose the set fields here! OK, I have missed that part. Please make it explicit in the changelog. It is quite easy to get lost in the deep call chains. -- Michal Hocko SUSE Labs