From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758673Ab1E0Bc0 (ORCPT ); Thu, 26 May 2011 21:32:26 -0400 Received: from relay1.sgi.com ([192.48.179.29]:58593 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753013Ab1E0BcZ (ORCPT ); Thu, 26 May 2011 21:32:25 -0400 Message-Id: <20110527013221.551591112@gulag1.americas.sgi.com> References: <20110527013221.231071058@gulag1.americas.sgi.com> User-Agent: quilt/0.46-1 Date: Thu, 26 May 2011 20:32:23 -0500 From: Mike Travis To: David Woodhouse , Chris Wright , Andrew Morton , Ingo Molnar Cc: Mike Habeck , Jesse Barnes , stable@kernel.org, iommu@lists.linux-foundation.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 2/7] Intel pci: Speed up processing of the identity_mapping function Content-Disposition: inline; filename=speed-up-iommu_no_mapping.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When there are a large count of PCI devices, and the pass through option for iommu is set, much time is spent in the identity_mapping function hunting though the iommu domains to check if a specific device is "identity mapped". Speed up the function by checking the cached info to see if it's mapped to the static identity domain. Signed-off-by: Mike Travis --- drivers/pci/intel-iommu.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- linux.orig/drivers/pci/intel-iommu.c +++ linux/drivers/pci/intel-iommu.c @@ -2106,10 +2106,10 @@ static int identity_mapping(struct pci_d if (likely(!iommu_identity_mapping)) return 0; + info = pdev->dev.archdata.iommu; + if (info && info != DUMMY_DEVICE_DOMAIN_INFO) + return (info->domain == si_domain); - list_for_each_entry(info, &si_domain->devices, link) - if (info->dev == pdev) - return 1; return 0; } --