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=-10.9 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 63D89C433E2 for ; Fri, 4 Sep 2020 07:00:22 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 21A7320722 for ; Fri, 4 Sep 2020 07:00:22 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 21A7320722 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 9AE376B0072; Fri, 4 Sep 2020 03:00:21 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 936DD6B0073; Fri, 4 Sep 2020 03:00:21 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7D8286B0074; Fri, 4 Sep 2020 03:00:21 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0186.hostedemail.com [216.40.44.186]) by kanga.kvack.org (Postfix) with ESMTP id 622FA6B0072 for ; Fri, 4 Sep 2020 03:00:21 -0400 (EDT) Received: from smtpin12.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 1F9A6181AC9CB for ; Fri, 4 Sep 2020 07:00:21 +0000 (UTC) X-FDA: 77224480242.12.baby09_060ecbb270b0 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin12.hostedemail.com (Postfix) with ESMTP id E42771801D1EB for ; Fri, 4 Sep 2020 07:00:20 +0000 (UTC) X-HE-Tag: baby09_060ecbb270b0 X-Filterd-Recvd-Size: 5743 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf24.hostedemail.com (Postfix) with ESMTP for ; Fri, 4 Sep 2020 07:00:20 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 10272AD5F; Fri, 4 Sep 2020 07:00:20 +0000 (UTC) Subject: Re: [PATCH v5 3/3] xen: add helpers to allocate unpopulated memory To: =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= Cc: linux-kernel@vger.kernel.org, Oleksandr Andrushchenko , David Airlie , Daniel Vetter , Boris Ostrovsky , Stefano Stabellini , Dan Carpenter , Wei Liu , Yan Yankovskyi , dri-devel@lists.freedesktop.org, xen-devel@lists.xenproject.org, linux-mm@kvack.org, David Hildenbrand , Michal Hocko , Dan Williams References: <20200901083326.21264-1-roger.pau@citrix.com> <20200901083326.21264-4-roger.pau@citrix.com> <20200903163837.GM753@Air-de-Roger> From: =?UTF-8?B?SsO8cmdlbiBHcm/Dnw==?= Message-ID: <6fd73d30-5525-7f00-1e9c-d7bb96ea34a6@suse.com> Date: Fri, 4 Sep 2020 09:00:18 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: <20200903163837.GM753@Air-de-Roger> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US X-Rspamd-Queue-Id: E42771801D1EB 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: On 03.09.20 18:38, Roger Pau Monn=C3=A9 wrote: > On Thu, Sep 03, 2020 at 05:30:07PM +0200, J=C3=BCrgen Gro=C3=9F wrote: >> On 01.09.20 10:33, Roger Pau Monne wrote: >>> To be used in order to create foreign mappings. This is based on the >>> ZONE_DEVICE facility which is used by persistent memory devices in >>> order to create struct pages and kernel virtual mappings for the IOME= M >>> areas of such devices. Note that on kernels without support for >>> ZONE_DEVICE Xen will fallback to use ballooned pages in order to >>> create foreign mappings. >>> >>> The newly added helpers use the same parameters as the existing >>> {alloc/free}_xenballooned_pages functions, which allows for in-place >>> replacement of the callers. Once a memory region has been added to be >>> used as scratch mapping space it will no longer be released, and page= s >>> returned are kept in a linked list. This allows to have a buffer of >>> pages and prevents resorting to frequent additions and removals of >>> regions. >>> >>> If enabled (because ZONE_DEVICE is supported) the usage of the new >>> functionality untangles Xen balloon and RAM hotplug from the usage of >>> unpopulated physical memory ranges to map foreign pages, which is the >>> correct thing to do in order to avoid mappings of foreign pages depen= d >>> on memory hotplug. >>> >>> Note the driver is currently not enabled on Arm platforms because it >>> would interfere with the identity mapping required on some platforms. >>> >>> Signed-off-by: Roger Pau Monn=C3=A9 >> >> Sorry, I just got a build error for x86 32-bit build: >> >> WARNING: unmet direct dependencies detected for ZONE_DEVICE >> Depends on [n]: MEMORY_HOTPLUG [=3Dn] && MEMORY_HOTREMOVE [=3Dn] && >> SPARSEMEM_VMEMMAP [=3Dn] && ARCH_HAS_PTE_DEVMAP [=3Dn] >> Selected by [y]: >> - XEN_UNPOPULATED_ALLOC [=3Dy] && XEN [=3Dy] && X86 [=3Dy] >> GEN Makefile >> CC kernel/bounds.s >> CALL /home/gross/korg/src/scripts/atomic/check-atomics.sh >> UPD include/generated/bounds.h >> CC arch/x86/kernel/asm-offsets.s >> In file included from /home/gross/korg/src/include/linux/mmzone.h:19:0= , >> from /home/gross/korg/src/include/linux/gfp.h:6, >> from /home/gross/korg/src/include/linux/slab.h:15, >> from /home/gross/korg/src/include/linux/crypto.h:19, >> from /home/gross/korg/src/arch/x86/kernel/asm-offset= s.c:9: >> /home/gross/korg/src/include/linux/page-flags-layout.h:95:2: error: #e= rror >> "Not enough bits in page flags" >> #error "Not enough bits in page flags" >> ^~~~~ >> make[2]: *** [/home/gross/korg/src/scripts/Makefile.build:114: >> arch/x86/kernel/asm-offsets.s] Error 1 >> make[1]: *** [/home/gross/korg/src/Makefile:1175: prepare0] Error 2 >> make[1]: Leaving directory '/home/gross/korg/x8632' >> make: *** [Makefile:185: __sub-make] Error 2 >=20 > Sorry for this. I've tested a 32bit build but I think it was before > the last Kconfig changes. I'm a little unsure how to solve this, as > ZONE_DEVICE doesn't select the required options for it to run, but > rather depends on them to be available. >=20 > You can trigger something similar on x86-64 by doing: >=20 > $ make ARCH=3Dx86_64 xen.config > Using .config as base > Merging ./kernel/configs/xen.config > Merging ./arch/x86/configs/xen.config > # > # merged configuration written to .config (needs make) > # > scripts/kconfig/conf --olddefconfig Kconfig >=20 > WARNING: unmet direct dependencies detected for ZONE_DEVICE > Depends on [n]: MEMORY_HOTPLUG [=3Dy] && MEMORY_HOTREMOVE [=3Dn] && = SPARSEMEM_VMEMMAP [=3Dy] && ARCH_HAS_PTE_DEVMAP [=3Dy] > Selected by [y]: > - XEN_UNPOPULATED_ALLOC [=3Dy] && XEN [=3Dy] && X86_64 [=3Dy] > # > # configuration written to .config > # >=20 > I think the only solution is to have XEN_UNPOPULATED_ALLOC depend on > ZONE_DEVICE rather than select it? Yes, I think so. I've folded that in and now build is fine. Juergen