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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_SANE_1 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 549BAC433DF for ; Fri, 5 Jun 2020 10:46:34 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 1A5C12075B for ; Fri, 5 Jun 2020 10:46:34 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1A5C12075B 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 9849B80007; Fri, 5 Jun 2020 06:46:33 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 934EA8E0006; Fri, 5 Jun 2020 06:46:33 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 84AE180007; Fri, 5 Jun 2020 06:46:33 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0157.hostedemail.com [216.40.44.157]) by kanga.kvack.org (Postfix) with ESMTP id 704908E0006 for ; Fri, 5 Jun 2020 06:46:33 -0400 (EDT) Received: from smtpin15.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 23730181AC9CB for ; Fri, 5 Jun 2020 10:46:33 +0000 (UTC) X-FDA: 76894829466.15.stove76_3d0725226d9f Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin15.hostedemail.com (Postfix) with ESMTP id 0313E1814B0C1 for ; Fri, 5 Jun 2020 10:46:32 +0000 (UTC) X-HE-Tag: stove76_3d0725226d9f X-Filterd-Recvd-Size: 3674 Received: from out30-131.freemail.mail.aliyun.com (out30-131.freemail.mail.aliyun.com [115.124.30.131]) by imf36.hostedemail.com (Postfix) with ESMTP for ; Fri, 5 Jun 2020 10:46:31 +0000 (UTC) X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R171e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01f04397;MF=alex.shi@linux.alibaba.com;NM=1;PH=DS;RN=39;SR=0;TI=SMTPD_---0U-e32eJ_1591353986; Received: from IT-FVFX43SYHV2H.local(mailfrom:alex.shi@linux.alibaba.com fp:SMTPD_---0U-e32eJ_1591353986) by smtp.aliyun-inc.com(127.0.0.1); Fri, 05 Jun 2020 18:46:27 +0800 Subject: Re: [PATCH RFC v4 00/13] virtio-mem: paravirtualized memory To: David Hildenbrand , linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, virtio-dev@lists.oasis-open.org, virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, Michal Hocko , Andrew Morton , "Michael S . Tsirkin" , Sebastien Boeuf , Samuel Ortiz , Robert Bradford , Luiz Capitulino , Alexander Duyck , Alexander Potapenko , Alexander Viro , Anshuman Khandual , Anthony Yznaga , Dan Williams , Dave Young , Igor Mammedov , Jason Wang , Johannes Weiner , Juergen Gross , Konrad Rzeszutek Wilk , Len Brown , Mel Gorman , Michal Hocko , Mike Rapoport , Oscar Salvador , Oscar Salvador , Pavel Tatashin , Pavel Tatashin , Pingfan Liu , Qian Cai , "Rafael J. Wysocki" , Stefan Hajnoczi , Vlastimil Babka , Wei Yang References: <20191212171137.13872-1-david@redhat.com> <9acc5d04-c8e9-ef53-85e4-709030997ca6@redhat.com> <1cfa9edb-47ea-1495-4e28-4cf391eab44c@linux.alibaba.com> <6b4724bf-84b5-9880-5464-1908425d106d@redhat.com> From: Alex Shi Message-ID: <95c6ef21-23e0-c768-999d-3af7f69d02d3@linux.alibaba.com> Date: Fri, 5 Jun 2020 18:46:26 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 X-Rspamd-Queue-Id: 0313E1814B0C1 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam03 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: =E5=9C=A8 2020/6/5 =E4=B8=8B=E5=8D=886:05, David Hildenbrand =E5=86=99=E9= =81=93: >> I guess I know what's happening here. In case we only have DMA memory >> when booting, we don't reserve swiotlb buffers. Once we hotplug memory >> and online ZONE_NORMAL, we don't have any swiotlb DMA bounce buffers t= o >> map such PFNs (total 0 (slots), used 0 (slots)). >> >> Can you try with "swiotlb=3Dforce" on the kernel cmdline? > Alternative, looks like you can specify "-m 2G,maxmem=3D16G,slots=3D1",= to > create proper ACPI tables that indicate hotpluggable memory. (I'll have > to look into QEMU to figure out to always indicate hotpluggable memory > that way). >=20 That works too. Yes, better resolved in qemu, maybe. :) Thanks!