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由 mark gross 提交于
This patch is for batching up the flushing of the IOTLB for the DMAR implementation found in the Intel VT-d hardware. It works by building a list of to be flushed IOTLB entries and a bitmap list of which DMAR engine they are from. After either a high water mark (250 accessible via debugfs) or 10ms the list of iova's will be reclaimed and the DMAR engines associated are IOTLB-flushed. This approach recovers 15 to 20% of the performance lost when using the IOMMU for my netperf udp stream benchmark with small packets. It can be disabled with a kernel boot parameter "intel_iommu=strict". Its use does weaken the IOMMU protections a bit. Signed-off-by: NMark Gross <mgross@linux.intel.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
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