From owner-freebsd-arch Sun Oct 13 5: 7:32 2002 Delivered-To: freebsd-arch@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 2DB5B37B404 for ; Sun, 13 Oct 2002 05:07:31 -0700 (PDT) Received: from harmony.village.org (rover.bsdimp.com [204.144.255.66]) by mx1.FreeBSD.org (Postfix) with ESMTP id 6095843E6A for ; Sun, 13 Oct 2002 05:07:30 -0700 (PDT) (envelope-from imp@bsdimp.com) Received: from localhost (warner@rover2.village.org [10.0.0.1]) by harmony.village.org (8.12.3/8.12.3) with ESMTP id g9DC7Bpk013086; Sun, 13 Oct 2002 06:07:11 -0600 (MDT) (envelope-from imp@bsdimp.com) Date: Sun, 13 Oct 2002 06:06:48 -0600 (MDT) Message-Id: <20021013.060648.93373269.imp@bsdimp.com> To: ticso@cicely.de, ticso@cicely8.cicely.de Cc: hch@infradead.org, wes@softweyr.com, dillon@apollo.backplane.com, vova@sw.ru, nate@root.org, arch@FreeBSD.org Subject: Re: Database indexes and ram From: "M. Warner Losh" In-Reply-To: <20021013103538.GG17920@cicely8.cicely.de> References: <20021012135245.A16453@infradead.org> <20021012.150616.129769790.imp@bsdimp.com> <20021013103538.GG17920@cicely8.cicely.de> X-Mailer: Mew version 2.1 on Emacs 21.2 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-freebsd-arch@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG In message: <20021013103538.GG17920@cicely8.cicely.de> Bernd Walter writes: : On Sat, Oct 12, 2002 at 03:06:16PM -0600, M. Warner Losh wrote: : > In message: <20021012135245.A16453@infradead.org> : > Christoph Hellwig writes: : > : On Wed, Oct 09, 2002 at 04:57:37PM -0700, Wes Peters wrote: : > : > Linux solved this problem by refusing to do it. The candidates for DMA : > : > transfers include skbufs and buffers from the disk buffer pool, both of : > : > which are allocated from the lowest 4GB of physical ram when using PAE : > : > mode. : > : : > : Umm, Linux _does_ DMA into any memory if the NIC/HBA/whatever supports : > : it. : > : > Unless the card is 64bit, it can't DMA past 4G. : : Shouldn't all modern pci chips support two 32bit word addresses. I don't think so. There's only 32-bits on the bus for the address on most pci cards (not the 64-bit pci cards, which are special), so I don't see how they can go above 4G. Unless I'm being unusually dense this morning. Warner To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message