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 78610C433E0 for ; Thu, 25 Jun 2020 22:39:58 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 486A320789 for ; Thu, 25 Jun 2020 22:39:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 486A320789 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 DBF826B0003; Thu, 25 Jun 2020 18:39:57 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D6F9B6B0005; Thu, 25 Jun 2020 18:39:57 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C843A6B0006; Thu, 25 Jun 2020 18:39:57 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0234.hostedemail.com [216.40.44.234]) by kanga.kvack.org (Postfix) with ESMTP id AF3F26B0003 for ; Thu, 25 Jun 2020 18:39:57 -0400 (EDT) Received: from smtpin26.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 2238E824CA22 for ; Thu, 25 Jun 2020 22:39:57 +0000 (UTC) X-FDA: 76969203234.26.jump81_4911eef26e50 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin26.hostedemail.com (Postfix) with ESMTP id EE5B51804B656 for ; Thu, 25 Jun 2020 22:39:56 +0000 (UTC) X-HE-Tag: jump81_4911eef26e50 X-Filterd-Recvd-Size: 3007 Received: from out30-57.freemail.mail.aliyun.com (out30-57.freemail.mail.aliyun.com [115.124.30.57]) by imf06.hostedemail.com (Postfix) with ESMTP for ; Thu, 25 Jun 2020 22:39:55 +0000 (UTC) X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R371e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e07425;MF=richard.weiyang@linux.alibaba.com;NM=1;PH=DS;RN=9;SR=0;TI=SMTPD_---0U0i1MZd_1593124792; Received: from localhost(mailfrom:richard.weiyang@linux.alibaba.com fp:SMTPD_---0U0i1MZd_1593124792) by smtp.aliyun-inc.com(127.0.0.1); Fri, 26 Jun 2020 06:39:52 +0800 Date: Fri, 26 Jun 2020 06:39:52 +0800 From: Wei Yang To: David Hildenbrand Cc: Dan Williams , 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: <20200625223952.GA17926@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: <4D73CD59-BFD5-401A-A001-41F7BF5641BA@redhat.com> X-Rspamd-Queue-Id: EE5B51804B656 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam04 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 07:53:37AM +0200, David Hildenbrand wrote: > > >> Am 25.06.2020 um 01:47 schrieb Dan Williams = : >>=20 >> =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 casing >>>> is problematic in retrospect as section_deactivate() can't be >>>> maintained without understand special rules in section_activate(). >>>=20 >>> Hmm... This means we need to adjust pfn_valid() too, which always ret= urn true >>> for early sections. >>=20 >> Right, rather than carry workarounds in 3 locations, and the bug that >> has resulted from then getting out of sync, just teach early section >> mapping to allow for the subsection populate/depopulate. >>=20 > >I prefer the easy fix first - IOW what we Here here. Especially, pfn_to_= online_page() will need changes as well. > Hi, David, Which part of pfn_to_online_page() needs to be changed? pfn_valid_within(= ) would call pfn_valid() to check the pfn first. This looks enough for me. I may not follow you at this part. >At least my ack stands. --=20 Wei Yang Help you, Help me