From owner-freebsd-hackers@FreeBSD.ORG Thu Nov 15 15:41:50 2007 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 9748F16A41B for ; Thu, 15 Nov 2007 15:41:50 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from elvis.mu.org (elvis.mu.org [192.203.228.196]) by mx1.freebsd.org (Postfix) with ESMTP id 7B9BD13C4C5 for ; Thu, 15 Nov 2007 15:41:50 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from zion.baldwin.cx (66-23-211-162.clients.speedfactory.net [66.23.211.162]) by elvis.mu.org (Postfix) with ESMTP id C35CD1A4D7E; Thu, 15 Nov 2007 07:23:31 -0800 (PST) From: John Baldwin To: freebsd-hackers@freebsd.org Date: Thu, 15 Nov 2007 07:42:15 -0500 User-Agent: KMail/1.9.7 References: <473B624D.5050904@charter.net> In-Reply-To: <473B624D.5050904@charter.net> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200711150742.16251.jhb@freebsd.org> Cc: icantthinkofone Subject: Re: FreeBSD cache 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: Thu, 15 Nov 2007 15:41:50 -0000 On Wednesday 14 November 2007 04:02:05 pm icantthinkofone wrote: > On Wednesday 14 November 2007 11:11:41 am Rob Belics wrote: > > > Someone I can't stand said this about FreeBSD. Though I know C, I > don't > > > know anything about this and would love to respond. My first > thought was > > > 'contigmalloc' but I'm not sure it's equivalent. > > > [QUOTE]The kernel is really lacking some features. They need a > method to > > > set precise type of memory cache but BSD doesn't provide way to > specify > > > memory cache. > > > > > > For that reason MS has the beautiful > > > MmAllocateContigousMemorySpecifyCache()[/QUOTE] > > For kernel memory on i386 and amd64 in 6.3 and later you can use > pmap_change_attr() to adjust the caching mode of memory after you have > allocated it. It is best used only with allocations that are a > multiple of > the page size. > > -- John Baldwin > > I posted using the wrong email address above. > > Apparently the person I was referring to was probably talking about he > nvidia issue and I see you, John, are working on that pmap function. > One question I have is whether nvidia got themselves into a bind (for > lack of a better word) because they wrote their drive using Windows > functions but now want FreeBSD to create kernel functions "just like > Windows" rather than rewriting their own code. Or is all this truly a > lacking feature in FreeBSD? It's a lacking feature in FreeBSD. -- John Baldwin