From owner-freebsd-emulation@FreeBSD.ORG Mon Dec 5 22:23:12 2011 Return-Path: Delivered-To: freebsd-emulation@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id A447A1065670; Mon, 5 Dec 2011 22:23:12 +0000 (UTC) (envelope-from alc@rice.edu) Received: from mh5.mail.rice.edu (mh5.mail.rice.edu [128.42.199.32]) by mx1.freebsd.org (Postfix) with ESMTP id 6775C8FC0A; Mon, 5 Dec 2011 22:23:12 +0000 (UTC) Received: from mh5.mail.rice.edu (localhost.localdomain [127.0.0.1]) by mh5.mail.rice.edu (Postfix) with ESMTP id F0952290FC5; Mon, 5 Dec 2011 16:23:10 -0600 (CST) Received: from mh5.mail.rice.edu (localhost.localdomain [127.0.0.1]) by mh5.mail.rice.edu (Postfix) with ESMTP id 14C15290F40; Mon, 5 Dec 2011 16:23:10 -0600 (CST) X-Virus-Scanned: by amavis-2.6.4 at mh5.mail.rice.edu, auth channel Received: from mh5.mail.rice.edu ([127.0.0.1]) by mh5.mail.rice.edu (mh5.mail.rice.edu [127.0.0.1]) (amavis, port 10026) with ESMTP id j8MDXWYX3H-u; Mon, 5 Dec 2011 16:23:09 -0600 (CST) Received: from [10.74.20.46] (staff-74-dun20-046.rice.edu [10.74.20.46]) (using TLSv1 with cipher RC4-MD5 (128/128 bits)) (No client certificate requested) (Authenticated sender: alc) by mh5.mail.rice.edu (Postfix) with ESMTPSA id C0D88290FE3; Mon, 5 Dec 2011 16:23:04 -0600 (CST) Message-ID: <4EDD442C.9030406@rice.edu> Date: Mon, 05 Dec 2011 16:22:36 -0600 From: Alan Cox User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:8.0) Gecko/20111105 Thunderbird/8.0 MIME-Version: 1.0 To: Andriy Gapon References: <4ECF7440.4070300@entel.upc.edu> <20111126163343.GA9150@reks> "<4ED6AEFE.4010106@FreeBSD.org>" <201111301807.21351.jkim@FreeBSD.org> <60ea779052f025798cf65e18c24b7b31@bluelife.at> <47eb9f9b139dd8c59b050f1670a5f18d@bluelife.at> <7c3c9505867f4528af276a571077b9ce@bluelife.at> <4EDCC1C6.3040109@FreeBSD.org> <4EDCCDA2.5070006@FreeBSD.org> <4EDD0644.5030902@rice.edu> <4EDD3F60.8050601@FreeBSD.org> In-Reply-To: <4EDD3F60.8050601@FreeBSD.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Alan Cox , freebsd-emulation@FreeBSD.org, FreeBSD current Subject: Re: Freeze with 10.0 and VirtualBox {4.1.4|4.1.6|4.1.51r38464} X-BeenThere: freebsd-emulation@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Development of Emulators of other operating systems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 05 Dec 2011 22:23:12 -0000 On 12/5/2011 4:02 PM, Andriy Gapon wrote: > on 05/12/2011 19:58 Alan Cox said the following: >> On 12/05/2011 07:56, Andriy Gapon wrote: >>> Pages should be marked busy only for some special occasions, wired pages are not >>> normally busy; the correct explanation is quite a bit longer than this, the >>> comment in the code explains VPO_BUSY as "page is in transit". Right now this >>> flag doesn't seem tom affect vboxdrv code but it may lead to surprises when some >>> parts of code that are incorrect now are re-implemented properly: >>> http://article.gmane.org/gmane.os.freebsd.devel.emulation/9297 >> VM_ALLOC_NOOBJ implies that the returned page does not have VPO_BUSY set. From >> the comment at the head of both vm_page_alloc() and vm_page_alloc_contig(): >> >> * VM_ALLOC_NOOBJ page is not associated with an object and >> * should not have the flag VPO_BUSY set > Ah, oops, forgot about this. > >> With regard to the message that the above link points to, I suspect that the >> introduction of vm_page_alloc_contig() can be used to address the first problem >> that you point out. Specifically, one or more OBJT_PHYS vm objects could be >> created and passed to vm_map_find() and then vm_page_alloc_contig() could be >> used to fill these vm objects with memory. > That's exactly what I was trying to do when I encountered a need for > VM_ALLOC_NOOBJ - my object was not NULL. > Alan, BTW, is it safe to map an OBJT_PHYS object into the kernel_map and into a > user map (or a few of them) at the same time? > Yes, it is. Alan