intel-iommu: Speed up map routines by using cached domain ASAP (147202aa) · Commits · 戴 / test

We did before, in the end -- but it was at the bottom of a long stack of functions. Add an inline wrapper get_valid_domain_for_dev() which will use the cached one _first_ and only make the out-of-line call if it's not already set. This takes the average time taken for a 1-page intel_map_sg() from 5961 cycles to 4812 cycles on my Lenovo x200s test box -- a modest 20%. Signed-off-by:

David Woodhouse <David.Woodhouse@intel.com>

drivers/pci/intel-iommu.c

+13 −2

Original line number	Diff line number	Diff line
		@@ -2455,8 +2455,7 @@ static struct iova intel_alloc_iova(struct device dev,
		return iova;
		}

		static struct dmar_domain *
		get_valid_domain_for_dev(struct pci_dev *pdev)
		static struct dmar_domain __get_valid_domain_for_dev(struct pci_dev pdev)
		{
		struct dmar_domain *domain;
		int ret;
		@@ -2484,6 +2483,18 @@ get_valid_domain_for_dev(struct pci_dev *pdev)
		return domain;
		}

		static inline struct dmar_domain get_valid_domain_for_dev(struct pci_dev dev)
		{
		struct device_domain_info *info;

		/* No lock here, assumes no domain exit in normal case */
		info = dev->dev.archdata.iommu;
		if (likely(info))
		return info->domain;

		return __get_valid_domain_for_dev(dev);
		}

		static int iommu_dummy(struct pci_dev *pdev)
		{
		return pdev->dev.archdata.iommu == DUMMY_DEVICE_DOMAIN_INFO;

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