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Commit 16a75bbe authored by Jacob Pan's avatar Jacob Pan Committed by Joerg Roedel
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iommu/vt-d: Avoid superfluous IOTLB tracking in lazy mode



Intel IOMMU driver implements IOTLB flush queue with domain selective
or PASID selective invalidations. In this case there's no need to track
IOVA page range and sync IOTLBs, which may cause significant performance
hit.

This patch adds a check to avoid IOVA gather page and IOTLB sync for
the lazy path.

The performance difference on Sapphire Rapids 100Gb NIC is improved by
the following (as measured by iperf send):

w/o this fix~48 Gbits/s. with this fix ~54 Gbits/s

Cc: <stable@vger.kernel.org>
Fixes: 2a2b8eaa ("iommu: Handle freelists when using deferred flushing in iommu drivers")
Reviewed-by: default avatarRobin Murphy <robin.murphy@arm.com>
Reviewed-by: default avatarKevin Tian <kevin.tian@intel.com>
Tested-by: default avatarSanjay Kumar <sanjay.k.kumar@intel.com>
Signed-off-by: default avatarSanjay Kumar <sanjay.k.kumar@intel.com>
Signed-off-by: default avatarJacob Pan <jacob.jun.pan@linux.intel.com>
Link: https://lore.kernel.org/r/20230209175330.1783556-1-jacob.jun.pan@linux.intel.com


Signed-off-by: default avatarLu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
parent 60b1daa3
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