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=-7.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,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 B5D66C4338F for ; Tue, 10 Aug 2021 16:29:34 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 7282260F94 for ; Tue, 10 Aug 2021 16:29:34 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 7282260F94 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=xen.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.165436.302307 (Exim 4.92) (envelope-from ) id 1mDUcw-0002Go-3V; Tue, 10 Aug 2021 16:29:18 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 165436.302307; Tue, 10 Aug 2021 16:29:18 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1mDUcw-0002Gh-0f; Tue, 10 Aug 2021 16:29:18 +0000 Received: by outflank-mailman (input) for mailman id 165436; Tue, 10 Aug 2021 16:29:17 +0000 Received: from mail.xenproject.org ([104.130.215.37]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1mDUcv-0002Gb-4D for xen-devel@lists.xenproject.org; Tue, 10 Aug 2021 16:29:17 +0000 Received: from xenbits.xenproject.org ([104.239.192.120]) by mail.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1mDUcd-0001XZ-Fr; Tue, 10 Aug 2021 16:28:59 +0000 Received: from [54.239.6.180] (helo=a483e7b01a66.ant.amazon.com) by xenbits.xenproject.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.92) (envelope-from ) id 1mDUcd-0003pj-8A; Tue, 10 Aug 2021 16:28:59 +0000 X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=xen.org; s=20200302mail; h=Content-Transfer-Encoding:Content-Type:In-Reply-To: MIME-Version:Date:Message-ID:From:References:Cc:To:Subject; bh=ufEN2YPI7vQWWPQFNTZWby3Jz+fRhfxgoGnLI5FMfxQ=; b=WWJ1wi4cH8yN1S3sFv9ahIDmYa JnrKutxqcT4gtwAi9XknHnDQihZ6SZ2xrJjFB2l4acNUaaFGPE49uE7tVETwzqoyEw8XuDW6m3jVm +Waz5JhxwDQ2US86HNhZCLQfyQScobZorK97PpYBXZmTaQ5/wDwWx7xWOd4P1YsTU2+A=; Subject: Re: [RFC PATCH] xen/memory: Introduce a hypercall to provide unallocated space To: Oleksandr Cc: Stefano Stabellini , Andrew Cooper , xen-devel@lists.xenproject.org, Oleksandr Tyshchenko , Daniel De Graaf , "Daniel P. Smith" , Ian Jackson , Wei Liu , George Dunlap , Jan Beulich , Volodymyr Babchuk , =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= , Bertrand Marquis , Wei Chen References: <1627489110-25633-1-git-send-email-olekstysh@gmail.com> <80fafc01-f063-d6e5-1c08-7ad64550310c@citrix.com> <4de5ed21-379e-b618-44c8-924d88b1a519@citrix.com> <6a633f4e-13e0-4a2b-cf6e-35ef90ae977c@gmail.com> <5643d414-0b76-74a4-2c37-c7a99338d547@gmail.com> <6596ad08-8398-64dd-ef62-cd7bc6f7333e@gmail.com> <1d0ea55d-2e5a-daa7-9c60-c7a1c4b48fa1@gmail.com> <6947db7a-44d3-eb5f-c93e-1c1b88c62f29@xen.org> <736c38b3-0dfa-ccbf-6a6a-6da871f8aca0@gmail.com> From: Julien Grall Message-ID: <4f5be55d-062b-06d2-1e41-bac3ade0cc3a@xen.org> Date: Tue, 10 Aug 2021 17:28:55 +0100 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.12.0 MIME-Version: 1.0 In-Reply-To: <736c38b3-0dfa-ccbf-6a6a-6da871f8aca0@gmail.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit On 09/08/2021 22:18, Oleksandr wrote: > > On 09.08.21 23:45, Julien Grall wrote: > > > Hi Julien Hi Oleksandr, >> On 09/08/2021 19:24, Oleksandr wrote: >>> >>> On 09.08.21 18:42, Julien Grall wrote: >>> 1. If IOMMU is enabled for Dom0 -> provide holes found in Host DT as >>> safe ranges >>> >>> I would take into the account holes >= 1MB. >> >> May I ask why 1MB? > > Nothing special, just thinking to not bother with small regions which > would not be too useful overall, but could bloat resulting reg property. > > Anyway, I would be ok with any sizes. I was more interesting with the reasoning behind your choice rather than saying we want more. I agree that we may want to skip smaller region. I am guess that an high number of small regions will also increase the bookeeping in Linux. But I would probably suggest to align the safe region to a 2MB (superpage for 4KB page granularity) just because the backend (or even Xen) may be able to do some optimization there. Cheers, -- Julien Grall