From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261970AbTFOHCe (ORCPT ); Sun, 15 Jun 2003 03:02:34 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261985AbTFOHCe (ORCPT ); Sun, 15 Jun 2003 03:02:34 -0400 Received: from pizda.ninka.net ([216.101.162.242]:1988 "EHLO pizda.ninka.net") by vger.kernel.org with ESMTP id S261970AbTFOHC0 (ORCPT ); Sun, 15 Jun 2003 03:02:26 -0400 Date: Sun, 15 Jun 2003 00:11:07 -0700 (PDT) Message-Id: <20030615.001107.88478922.davem@redhat.com> To: anton@samba.org Cc: davidm@hpl.hp.com, davidm@napali.hpl.hp.com, manfred@colorfullife.com, axboe@suse.de, linux-kernel@vger.kernel.org Subject: Re: problem with blk_queue_bounce_limit() From: "David S. Miller" In-Reply-To: <20030615070611.GE31148@krispykreme> References: <16097.36514.763047.738847@napali.hpl.hp.com> <20030607.001140.08328499.davem@redhat.com> <20030615070611.GE31148@krispykreme> X-FalunGong: Information control. X-Mailer: Mew version 2.1 on Emacs 21.1 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org From: Anton Blanchard Date: Sun, 15 Jun 2003 17:06:11 +1000 Dave, we talked about this ages ago as a possible alternative to skb recycling and persistent IOMMU mappings for those skbs. Unfortunately you need a hash to map from all of memory to a pci bus address for each host bridge (well IOMMU), and so far I cant think of anything that wouldnt chew gobs of RAM. The hash table need not be sized wrt. ram, but rather to the expected amount of "DMA in flight" you can expect for the system. You have to make these tables per-IOMMU anyways, which breaks down the problem much further. ROFL, whose workstation name is krispykreme? :-) I just noticed that.