From owner-freebsd-arch Sun Oct 13 5: 9:26 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 8D36B37B401 for ; Sun, 13 Oct 2002 05:09:25 -0700 (PDT) Received: from harmony.village.org (rover.bsdimp.com [204.144.255.66]) by mx1.FreeBSD.org (Postfix) with ESMTP id DEA8D43E8A for ; Sun, 13 Oct 2002 05:09:24 -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 g9DC9Epk013099; Sun, 13 Oct 2002 06:09:15 -0600 (MDT) (envelope-from imp@bsdimp.com) Date: Sun, 13 Oct 2002 06:08:51 -0600 (MDT) Message-Id: <20021013.060851.113437955.imp@bsdimp.com> To: tlambert2@mindspring.com Cc: ticso@cicely.de, 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: <3DA954CF.98B0891A@mindspring.com> References: <20021012.150616.129769790.imp@bsdimp.com> <20021013103538.GG17920@cicely8.cicely.de> <3DA954CF.98B0891A@mindspring.com> 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: <3DA954CF.98B0891A@mindspring.com> Terry Lambert writes: : In most cases, the DMA gets put directly into memory mapped by the : VM of the kernel (the KVA). Actually, in most cases on i386 the memory gets DMAd to a phyiscal address, which is why there is a 4G limit in the hardware. Since it is a phyiscal address, knowing VM tricks I don't think is relevant. PAE is basically a vm trick. Warner To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message