From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 12 Feb 2008 01:00:06 -0800 (PST) Message-Id: <20080212.010006.255202479.davem@davemloft.net> Subject: Re: [PATCH]intel-iommu batched iotlb flushes From: David Miller In-Reply-To: <20080212085256.GF5750@rhun.haifa.ibm.com> References: <20080211224105.GB24412@linux.intel.com> <20080212085256.GF5750@rhun.haifa.ibm.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org From: Muli Ben-Yehuda Date: Tue, 12 Feb 2008 10:52:56 +0200 Return-Path: To: muli@il.ibm.com Cc: mgross@linux.intel.com, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: > The streaming DMA-API was designed to conserve IOMMU mappings for > machines where IOMMU mappings are a scarce resource, and is a poor > fit for a modern IOMMU such as VT-d with a 64-bit IO address space > (or even an IOMMU with a 32-bit address space such as Calgary) where > there are plenty of IOMMU mappings available. For the 64-bit case what you are suggesting eventually amounts to mapping all available RAM in the IOMMU. Although an extreme version of your suggestion, it would be the most efficient as it would require zero IOMMU flush operations. But we'd lose things like protection and other benefits. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org