lkml.org 
[lkml]   [2023]   [Aug]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] iommu/vt-d: Introduce a rb_tree for looking up device
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@intel.com>
> ---
> 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

\
 
 \ /
  Last update: 2023-08-21 18:53    [W:0.130 / U:0.100 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site