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Commit 147202aa authored by David Woodhouse's avatar David Woodhouse
Browse files

intel-iommu: Speed up map routines by using cached domain ASAP 



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: default avatarDavid Woodhouse <David.Woodhouse@intel.com>
parent 085ff82c

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;