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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,URIBL_BLOCKED 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 31765C433E1 for ; Thu, 25 Jun 2020 22:29:47 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id F040E20767 for ; Thu, 25 Jun 2020 22:29:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F040E20767 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 781B66B0003; Thu, 25 Jun 2020 18:29:46 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 7320A6B0005; Thu, 25 Jun 2020 18:29:46 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 647466B0006; Thu, 25 Jun 2020 18:29:46 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0246.hostedemail.com [216.40.44.246]) by kanga.kvack.org (Postfix) with ESMTP id 4AB3F6B0003 for ; Thu, 25 Jun 2020 18:29:46 -0400 (EDT) Received: from smtpin16.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id B157E824556B for ; Thu, 25 Jun 2020 22:29:45 +0000 (UTC) X-FDA: 76969177530.16.cent09_150972826e50 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin16.hostedemail.com (Postfix) with ESMTP id 83F8C100E6903 for ; Thu, 25 Jun 2020 22:29:45 +0000 (UTC) X-HE-Tag: cent09_150972826e50 X-Filterd-Recvd-Size: 3186 Received: from out30-56.freemail.mail.aliyun.com (out30-56.freemail.mail.aliyun.com [115.124.30.56]) by imf37.hostedemail.com (Postfix) with ESMTP for ; Thu, 25 Jun 2020 22:29:44 +0000 (UTC) X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R711e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01f04397;MF=richard.weiyang@linux.alibaba.com;NM=1;PH=DS;RN=9;SR=0;TI=SMTPD_---0U0hvnAM_1593124180; Received: from localhost(mailfrom:richard.weiyang@linux.alibaba.com fp:SMTPD_---0U0hvnAM_1593124180) by smtp.aliyun-inc.com(127.0.0.1); Fri, 26 Jun 2020 06:29:41 +0800 Date: Fri, 26 Jun 2020 06:29:40 +0800 From: Wei Yang To: Dan Williams Cc: David Hildenbrand , Wei Yang , Michal Hocko , Andrew Morton , Oscar Salvador , Linux MM , Baoquan He , Linux Kernel Mailing List Subject: Re: [PATCH] mm/spase: never partially remove memmap for early section Message-ID: <20200625222940.GA16822@L-31X9LVDL-1304.local> Reply-To: Wei Yang References: <4D73CD59-BFD5-401A-A001-41F7BF5641BA@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: X-Rspamd-Queue-Id: 83F8C100E6903 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam01 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, Jun 25, 2020 at 12:46:43PM -0700, Dan Williams wrote: >On Wed, Jun 24, 2020 at 10:53 PM David Hildenbrand wr= ote: >> >> >> >> > Am 25.06.2020 um 01:47 schrieb Dan Williams : >> > >> > =EF=BB=BFOn Wed, Jun 24, 2020 at 3:44 PM Wei Yang >> > wrote: >> > [..] >> >>> So, you are right that there is a mismatch here, but I think the >> >>> comprehensive fix is to allow early sections to be partially >> >>> depopulated/repopulated rather than have section_activate() and >> >>> section_deacticate() special case early sections. The special casi= ng >> >>> is problematic in retrospect as section_deactivate() can't be >> >>> maintained without understand special rules in section_activate(). >> >> >> >> Hmm... This means we need to adjust pfn_valid() too, which always r= eturn true >> >> for early sections. >> > >> > Right, rather than carry workarounds in 3 locations, and the bug tha= t >> > has resulted from then getting out of sync, just teach early section >> > mapping to allow for the subsection populate/depopulate. >> > >> >> I prefer the easy fix first - IOW what we Here here. Especially, pfn_t= o_online_page() will need changes as well. > >Agree, yes, let's do the simple fix first for 5.8 and the special-case >elimination work later. Ok, let me send v2 with detailed change log and a comment in code first. Thanks all for your time. --=20 Wei Yang Help you, Help me