lkml.org 
[lkml]   [2011]   [May]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH 2/7] Intel pci: Speed up processing of the identity_mapping function
    When there are a large count of PCI devices, and the pass
through option for iommu is set, much time is spent in the
identity_mapping function hunting though the iommu domains to
check if a specific device is "identity mapped".

Speed up the function by checking the cached info to see if
it's mapped to the static identity domain.

Signed-off-by: Mike Travis <travis@sgi.com>
---
drivers/pci/intel-iommu.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

--- linux.orig/drivers/pci/intel-iommu.c
+++ linux/drivers/pci/intel-iommu.c
@@ -2106,10 +2106,10 @@ static int identity_mapping(struct pci_d
if (likely(!iommu_identity_mapping))
return 0;

+ info = pdev->dev.archdata.iommu;
+ if (info && info != DUMMY_DEVICE_DOMAIN_INFO)
+ return (info->domain == si_domain);

- list_for_each_entry(info, &si_domain->devices, link)
- if (info->dev == pdev)
- return 1;
return 0;
}

--


\
 
 \ /
  Last update: 2011-05-27 03:35    [W:0.068 / U:0.164 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site