On Mon, Aug 21, 2023 at 12:16:59AM -0700, Huang Jiaqing wrote: > The existing IO page fault handler locates the PCI device by calling > pci_get_domain_bus_and_slot(), which searches the list of all PCI > devices until the desired PCI device is found. This is inefficient > because the algorithm efficiency of searching a list is O(n). In the > critical path of handling an IO page fault, this can cause a significant > performance bottleneck. > > To improve the performance of the IO page fault handler, replace > pci_get_domain_bus_and_slot() with a local red-black tree. A red-black > tree is a self-balancing binary search tree, which means that the > average time complexity of searching a red-black tree is O(log(n)). This > is significantly faster than O(n), so it can significantly improve the > performance of the IO page fault handler. > > In addition, we can only insert the affected devices (those that have IO > page fault enabled) into the red-black tree. This can further improve > the performance of the IO page fault handler. > > Signed-off-by: Huang Jiaqing <jiaqing.huang@xxxxxxxxx> > --- > drivers/iommu/intel/iommu.c | 68 +++++++++++++++++++++++++++++++++++++ > drivers/iommu/intel/iommu.h | 8 +++++ > drivers/iommu/intel/svm.c | 13 +++---- > 3 files changed, 81 insertions(+), 8 deletions(-) I feel like this should be a helper library provided by the core code, doesn't every PRI driver basically need the same thing? Jason
