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

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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>
This commit is contained in:
David Woodhouse 2009-07-07 19:43:20 +01:00
parent 085ff82c9c
commit 147202aa77
1 changed files with 13 additions and 2 deletions
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15
drivers/pci/intel-iommu.c
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@ -2455,8 +2455,7 @@ static struct iova *intel_alloc_iova(struct device *dev,
return iova; return iova;
} }
static struct dmar_domain * static struct dmar_domain *__get_valid_domain_for_dev(struct pci_dev *pdev)
get_valid_domain_for_dev(struct pci_dev *pdev)
{ {
struct dmar_domain *domain; struct dmar_domain *domain;
int ret; int ret;
@ -2484,6 +2483,18 @@ get_valid_domain_for_dev(struct pci_dev *pdev)
return domain; 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) static int iommu_dummy(struct pci_dev *pdev)
{ {
return pdev->dev.archdata.iommu == DUMMY_DEVICE_DOMAIN_INFO; return pdev->dev.archdata.iommu == DUMMY_DEVICE_DOMAIN_INFO;