From owner-freebsd-hackers@FreeBSD.ORG Wed Dec 15 18:26:41 2010 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 993EA106566C for ; Wed, 15 Dec 2010 18:26:41 +0000 (UTC) (envelope-from julian@freebsd.org) Received: from out-0.mx.aerioconnect.net (out-0-7.mx.aerioconnect.net [216.240.47.67]) by mx1.freebsd.org (Postfix) with ESMTP id 7BE668FC13 for ; Wed, 15 Dec 2010 18:26:41 +0000 (UTC) Received: from idiom.com (postfix@mx0.idiom.com [216.240.32.160]) by out-0.mx.aerioconnect.net (8.13.8/8.13.8) with ESMTP id oBFIQeXc024693; Wed, 15 Dec 2010 10:26:40 -0800 X-Client-Authorized: MaGic Cook1e X-Client-Authorized: MaGic Cook1e Received: from julian-mac.elischer.org (h-67-100-89-137.snfccasy.static.covad.net [67.100.89.137]) by idiom.com (Postfix) with ESMTP id 9ABFD2D6013; Wed, 15 Dec 2010 10:26:39 -0800 (PST) Message-ID: <4D09085D.7050006@freebsd.org> Date: Wed, 15 Dec 2010 10:26:37 -0800 From: Julian Elischer User-Agent: Mozilla/5.0 (Macintosh; U; PPC Mac OS X 10.4; en-US; rv:1.9.2.12) Gecko/20101027 Thunderbird/3.1.6 MIME-Version: 1.0 To: "Dr. Baud" References: <66322.83509.qm@web120712.mail.ne1.yahoo.com> In-Reply-To: <66322.83509.qm@web120712.mail.ne1.yahoo.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.67 on 216.240.47.51 Cc: freebsd-hackers@freebsd.org Subject: Re: Driver memory allocation X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 15 Dec 2010 18:26:41 -0000 On 12/15/10 4:33 AM, Dr. Baud wrote: > Is there a cap on the amount of memory a driver (via bus_dmamem_alloc) can > allocate, other than the obvious physical memory limit minus the memory already > allocated? > well it has to fit into the kernel virtual space too. this is quite limited on x86 though for amd64 it is a lot bigger. I have seen drivers on amd64 setting asside a couple of GB (but you need a new kernel that has the kernel virtual space expanded). The kernel can make use of the direct-map space for driver allocation too. > Dr. > > > > > _______________________________________________ > freebsd-hackers@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-hackers > To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.org" >