Messages in this thread Patch in this message | | | Date | Thu, 26 May 2011 20:32:23 -0500 | From | Mike Travis <> | Subject | [PATCH 2/7] Intel pci: Speed up processing of the identity_mapping function |
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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 <travis@sgi.com> --- 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; } --
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