From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EB334C433E4 for ; Fri, 24 Jul 2020 05:45:58 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 94FC420748 for ; Fri, 24 Jul 2020 05:45:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 94FC420748 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id F16558D0025; Fri, 24 Jul 2020 01:45:57 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E9FE98D0007; Fri, 24 Jul 2020 01:45:57 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D67D68D0025; Fri, 24 Jul 2020 01:45:57 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0189.hostedemail.com [216.40.44.189]) by kanga.kvack.org (Postfix) with ESMTP id BC82B8D0007 for ; Fri, 24 Jul 2020 01:45:57 -0400 (EDT) Received: from smtpin17.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 6326D18013217 for ; Fri, 24 Jul 2020 05:45:57 +0000 (UTC) X-FDA: 77071883154.17.curve70_63024cf26f44 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin17.hostedemail.com (Postfix) with ESMTP id 3086618015CC9 for ; Fri, 24 Jul 2020 05:45:57 +0000 (UTC) X-HE-Tag: curve70_63024cf26f44 X-Filterd-Recvd-Size: 4423 Received: from out30-133.freemail.mail.aliyun.com (out30-133.freemail.mail.aliyun.com [115.124.30.133]) by imf06.hostedemail.com (Postfix) with ESMTP for ; Fri, 24 Jul 2020 05:45:54 +0000 (UTC) X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R801e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e01358;MF=richard.weiyang@linux.alibaba.com;NM=1;PH=DS;RN=13;SR=0;TI=SMTPD_---0U3dvC2j_1595569548; Received: from localhost(mailfrom:richard.weiyang@linux.alibaba.com fp:SMTPD_---0U3dvC2j_1595569548) by smtp.aliyun-inc.com(127.0.0.1); Fri, 24 Jul 2020 13:45:48 +0800 Date: Fri, 24 Jul 2020 13:45:48 +0800 From: Wei Yang To: Andrew Morton Cc: Wei Yang , David Hildenbrand , Wei Yang , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Michal Hocko , stable@vger.kernel.org, Johannes Weiner , Minchan Kim , Huang Ying , Mel Gorman , Dan Williams Subject: Re: [PATCH v2 1/3] mm/shuffle: don't move pages between zones and don't read garbage memmaps Message-ID: <20200724054548.GA17189@L-31X9LVDL-1304.local> Reply-To: Wei Yang References: <2185539f-b210-5d3f-5da2-a497b354eebb@redhat.com> <20200622092221.GA96699@L-31X9LVDL-1304.local> <34f36733-805e-cc61-38da-2ee578ae096c@redhat.com> <20200622131003.GA98415@L-31X9LVDL-1304.local> <0f4edc1f-1ce2-95b4-5866-5c4888db7c65@redhat.com> <20200622215520.wa6gjr2hplurwy57@master> <4b7ee49c-9bee-a905-3497-e3addd8896b8@redhat.com> <20200623093018.GA6069@L-31X9LVDL-1304.local> <20200723200846.768513d7c122ac11b6e73538@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200723200846.768513d7c122ac11b6e73538@linux-foundation.org> X-Rspamd-Queue-Id: 3086618015CC9 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam04 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000001, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, Jul 23, 2020 at 08:08:46PM -0700, Andrew Morton wrote: >On Tue, 23 Jun 2020 17:30:18 +0800 Wei Yang wrote: > >> On Tue, Jun 23, 2020 at 09:55:43AM +0200, David Hildenbrand wrote: >> >On 23.06.20 09:39, David Hildenbrand wrote: >> >>> Hmm.. I thought this is the behavior for early section, while it looks current >> >>> code doesn't work like this: >> >>> >> >>> if (section_is_early && memmap) >> >>> free_map_bootmem(memmap); >> >>> else >> >>> depopulate_section_memmap(pfn, nr_pages, altmap); >> >>> >> >>> section_is_early is always "true" for early section, while memmap is not-NULL >> >>> only when sub-section map is empty. >> >>> >> >>> If my understanding is correct, when we remove a sub-section in early section, >> >>> the code would call depopulate_section_memmap(), which in turn free related >> >>> memmap. By removing the memmap, the return value from pfn_to_online_page() is >> >>> not a valid one. >> >> >> >> I think you're right, and pfn_valid() would also return true, as it is >> >> an early section. This looks broken. >> >> >> >>> >> >>> Maybe we want to write the code like this: >> >>> >> >>> if (section_is_early) >> >>> if (memmap) >> >>> free_map_bootmem(memmap); >> >>> else >> >>> depopulate_section_memmap(pfn, nr_pages, altmap); >> >>> >> >> >> >> I guess that should be the way to go >> >> >> >> @Dan, I think what Wei proposes here is correct, right? Or how does it >> >> work in the VMEMMAP case with early sections? >> >> >> > >> >Especially, if you would re-hot-add, section_activate() would assume >> >there is a memmap, it must not be removed. >> > >> >> You are right here. I didn't notice it. >> >> >@Wei, can you send a patch? >> > >> >> Sure, let me prepare for it. > >Still awaiting this, and the v3 patch was identical to this v2 patch. > >It's tagged for -stable, so there's some urgency. Should we just go >ahead with the decently-tested v2? This message is to me right? I thought the fix patch is merged, the patch link may be https://lkml.org/lkml/2020/6/23/380. If I missed something, just let me know. -- Wei Yang Help you, Help me