From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf1-f199.google.com (mail-pf1-f199.google.com [209.85.210.199]) by kanga.kvack.org (Postfix) with ESMTP id 52EFA8E0001 for ; Tue, 22 Jan 2019 03:52:38 -0500 (EST) Received: by mail-pf1-f199.google.com with SMTP id a23so17876005pfo.2 for ; Tue, 22 Jan 2019 00:52:38 -0800 (PST) Received: from prv1-mh.provo.novell.com (prv1-mh.provo.novell.com. [137.65.248.33]) by mx.google.com with ESMTPS id q2si16021899plh.261.2019.01.22.00.52.36 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 22 Jan 2019 00:52:37 -0800 (PST) Message-Id: <5C46D9D00200007800210007@prv1-mh.provo.novell.com> Date: Tue, 22 Jan 2019 01:52:32 -0700 From: "Jan Beulich" Subject: Re: [Xen-devel] [PATCH 2/2] x86/xen: dont add memory above max allowed allocation References: <20190122080628.7238-1-jgross@suse.com> <20190122080628.7238-3-jgross@suse.com> In-Reply-To: <20190122080628.7238-3-jgross@suse.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Sender: owner-linux-mm@kvack.org List-ID: To: Juergen Gross Cc: Borislav Petkov , Stefano Stabellini , the arch/x86 maintainers , linux-mm@kvack.org, tglx@linutronix.de, xen-devel , Boris Ostrovsky , mingo@redhat.com, linux-kernel@vger.kernel.org, hpa@zytor.com >>> On 22.01.19 at 09:06, wrote: > Don't allow memory to be added above the allowed maximum allocation > limit set by Xen. This reads as if the hypervisor was imposing a limit here, but looking at xen_get_max_pages(), xen_foreach_remap_area(), and xen_count_remap_pages() I take it that it's a restriction enforced by the Xen subsystem in Linux. Furthermore from the cover letter I imply that the observed issue was on a Dom0, yet xen_get_max_pages()'s use of XENMEM_maximum_reservation wouldn't impose any limit there at all (without use of the hypervisor option "dom0_mem=3Dmax:..."), would it? Jan 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_PASS 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 5C0E9C282C3 for ; Tue, 22 Jan 2019 08:52:39 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 16C232084C for ; Tue, 22 Jan 2019 08:52:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 16C232084C 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 A63778E0003; Tue, 22 Jan 2019 03:52:38 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 9EA678E0001; Tue, 22 Jan 2019 03:52:38 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 88CD18E0003; Tue, 22 Jan 2019 03:52:38 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from mail-pf1-f199.google.com (mail-pf1-f199.google.com [209.85.210.199]) by kanga.kvack.org (Postfix) with ESMTP id 52EFA8E0001 for ; Tue, 22 Jan 2019 03:52:38 -0500 (EST) Received: by mail-pf1-f199.google.com with SMTP id a23so17876005pfo.2 for ; Tue, 22 Jan 2019 00:52:38 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-original-authentication-results:x-gm-message-state:message-id :date:from:to:cc:subject:references:in-reply-to:mime-version :content-transfer-encoding:content-disposition; bh=ppLteORMlUtf/fi5TYtZzK4LVAiuFz2UaSAY2hsYxUk=; b=l19WwcV8erZ/09wJzMGG+3Wta0aTU1SutGQlkDDsVVmBnuzWaaKQvpka8u5EvdOD0a wKkVn+3mSk6B+d2ILlFDcpZ4QB9/4knLPCsldBJVkMgVBNQ0zX3gizIVcU6HZbGbrQxq NtGK/I59wfIQlXBCca1hAvu90JY62gg2Z5o4bYVCU+lFbk5uXbmxMvY99S0tomUIqLqD LFeXOfX+QZZYb0tuVv1R9RsWivW/LpldKLYfv2xnc+d01uzorvNNAcIeamOwI7LdLvwE tLITiCGD5wy7EdP0ZiHBE51hjGKVOADZeSyxa5/eMeDbOuepZ8j/75JIFbA5L5mB4eAf mylg== X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of jbeulich@suse.com designates 137.65.248.33 as permitted sender) smtp.mailfrom=JBeulich@suse.com X-Gm-Message-State: AJcUukeXpBk1SeOXdPoncRVYUn7e/9LM8nod0tugdey5B2jrBk4U2R/Z FKrhj4yHiac6n8WupuTuvVovunuTgmc1WMaC1Y4VyPTLYtxNLNSvQHzO0pdpr1yXrL6AqhR+Xwb 7K+vTAYX6O5qJK15BMYViebYhUFSvTnA3qJGTE0g04aiPxUsgOXIc1XL8UdmVDMRDgw== X-Received: by 2002:a62:a510:: with SMTP id v16mr32534042pfm.18.1548147157961; Tue, 22 Jan 2019 00:52:37 -0800 (PST) X-Google-Smtp-Source: ALg8bN595o21y+WSFVPuQ7Xu5aZcBorOxAaY8de0hptwwZeJRyP9Ko63bQyvLfNAb5hW5J/q/OVE X-Received: by 2002:a62:a510:: with SMTP id v16mr32534014pfm.18.1548147157168; Tue, 22 Jan 2019 00:52:37 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1548147157; cv=none; d=google.com; s=arc-20160816; b=d3bnRSXLGDav28/H+5wMcVpFqRsEq8VCUEzbXVZRyCDtwGcRxLTg2aD6skuWbTHOq/ E3Sz5ommDX5oJ4QqX1g1xbV2ucDKmf9RXTqQ6bGFaJ7sM9SxVcH3+asq0GkqAmw11duz x9+3WWQGqAnmrGY28bd/GNJjiVB6Lbe/gjEvlrrShKf3xe2hk8BDF9seLA8pIuliFjzt 3NFVhRlT2Rg4yhCflIXylGuvDX7o65lClgXPLF7hcFb4RPUxqdjX2i75xYFCJDYMZyfi SnzbQS6FLJQbDQOwAvTTuC9n8/V7xQ6AqHiPU86JoLCiT8V/e0VC8tOfhH0LXjpbPuL5 5ckg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=content-disposition:content-transfer-encoding:mime-version :in-reply-to:references:subject:cc:to:from:date:message-id; bh=ppLteORMlUtf/fi5TYtZzK4LVAiuFz2UaSAY2hsYxUk=; b=gDFU8EJH3kQP5XYRh8yus3EU3I92TjF7Wq/ozsuC5sZwypVnfOKUjMCYxAUOygNiGH XdfHCcRoP2XH6tTWJzBFegkdGqQDHvsAMJDFSK+1Bn0GPLK1mIIOYK7N4z69ZGo9Ow4e KZoOgAeOkBvVAnkctbGYArgbu2ewO8AyTP2d+3Esl7XJ1OFhDrbXgNFAvOp4yKxkZinj UMxFyt4CEW+ilE65wNPxWniSHCnYG3se6gavs10f37BpatFJIpvcFjbpEgOZTzBqKED3 0CkV2+t5rJ0iytN2HVG8mIb1xqEC+E9Zj2pLeYKtArvYgfkOlLMAq2TkYZJrLkxGq1mA ikdQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of jbeulich@suse.com designates 137.65.248.33 as permitted sender) smtp.mailfrom=JBeulich@suse.com Received: from prv1-mh.provo.novell.com (prv1-mh.provo.novell.com. [137.65.248.33]) by mx.google.com with ESMTPS id q2si16021899plh.261.2019.01.22.00.52.36 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 22 Jan 2019 00:52:37 -0800 (PST) Received-SPF: pass (google.com: domain of jbeulich@suse.com designates 137.65.248.33 as permitted sender) client-ip=137.65.248.33; Authentication-Results: mx.google.com; spf=pass (google.com: domain of jbeulich@suse.com designates 137.65.248.33 as permitted sender) smtp.mailfrom=JBeulich@suse.com Received: from INET-PRV1-MTA by prv1-mh.provo.novell.com with Novell_GroupWise; Tue, 22 Jan 2019 01:52:36 -0700 Message-Id: <5C46D9D00200007800210007@prv1-mh.provo.novell.com> X-Mailer: Novell GroupWise Internet Agent 18.1.0 Date: Tue, 22 Jan 2019 01:52:32 -0700 From: "Jan Beulich" To: "Juergen Gross" Cc: "Borislav Petkov" , "Stefano Stabellini" , "the arch/x86 maintainers" ,, , "xen-devel" , "Boris Ostrovsky" , , , Subject: Re: [Xen-devel] [PATCH 2/2] x86/xen: dont add memory above max allowed allocation References: <20190122080628.7238-1-jgross@suse.com> <20190122080628.7238-3-jgross@suse.com> In-Reply-To: <20190122080628.7238-3-jgross@suse.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline 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: Message-ID: <20190122085232.3EbMoT2d_s-8RR8mXewYIu5TmMdUTdb7D9T3Rd7dW4Q@z> >>> On 22.01.19 at 09:06, wrote: > Don't allow memory to be added above the allowed maximum allocation > limit set by Xen. This reads as if the hypervisor was imposing a limit here, but looking at xen_get_max_pages(), xen_foreach_remap_area(), and xen_count_remap_pages() I take it that it's a restriction enforced by the Xen subsystem in Linux. Furthermore from the cover letter I imply that the observed issue was on a Dom0, yet xen_get_max_pages()'s use of XENMEM_maximum_reservation wouldn't impose any limit there at all (without use of the hypervisor option "dom0_mem=3Dmax:..."), would it? Jan