From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753426AbdHKPWq (ORCPT ); Fri, 11 Aug 2017 11:22:46 -0400 Received: from mx2.suse.de ([195.135.220.15]:38665 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753148AbdHKPWo (ORCPT ); Fri, 11 Aug 2017 11:22:44 -0400 Date: Fri, 11 Aug 2017 17:22:41 +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 00/15] complete deferred page initialization Message-ID: <20170811152240.GQ30811@dhcp22.suse.cz> References: <1502138329-123460-1-git-send-email-pasha.tatashin@oracle.com> <20170811075826.GB30811@dhcp22.suse.cz> <23e22449-89f0-507d-e92a-9ee947a7c363@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <23e22449-89f0-507d-e92a-9ee947a7c363@oracle.com> 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 11:13:07, Pasha Tatashin wrote: > On 08/11/2017 03:58 AM, Michal Hocko wrote: > >[I am sorry I didn't get to your previous versions] > > Thank you for reviewing this work. I will address your comments, and > send-out a new patches. > > >> > >>In this work we do the following: > >>- Never read access struct page until it was initialized > > > >How is this enforced? What about pfn walkers? E.g. page_ext > >initialization code (page owner in particular) > > This is hard to enforce 100%. But, because we have a patch in this series > that sets all memory that was allocated by memblock_virt_alloc_try_nid_raw() > to ones with debug options enabled, and because Linux has a good set of > asserts in place that check struct pages to be sane, especially the ones > that are enabled with this config: CONFIG_DEBUG_VM_PGFLAGS. I was able to > find many places in linux which accessed struct pages before > __init_single_page() is performed, and fix them. Most of these places happen > only when deferred struct page initialization code is enabled. Yes, I am very well aware of how hard is this to guarantee. I was merely pointing out that the changelog should be more verbose about your testing and assumptions so that we can revalidate them. -- Michal Hocko SUSE Labs