From 1ba6ab11d8fbd8d29afec4e39236e1255ae0339a Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Wed, 13 Feb 2008 15:06:38 -0800 Subject: PCI: remove initial bios sort of PCI devices on x86 We currently keep 2 lists of PCI devices in the system, one in the driver core, and one all on its own. This second list is sorted at boot time, in "BIOS" order, to try to remain compatible with older kernels (2.2 and earlier days). There was also a "nosort" option to turn this sorting off, to remain compatible with even older kernel versions, but that just ends up being what we have been doing from 2.5 days... Unfortunately, the second list of devices is not really ever used to determine the probing order of PCI devices or drivers[1]. That is done using the driver core list instead. This change happened back in the early 2.5 days. Relying on BIOS ording for the binding of drivers to specific device names is problematic for many reasons, and userspace tools like udev exist to properly name devices in a persistant manner if that is needed, no reliance on the BIOS is needed. Matt Domsch and others at Dell noticed this back in 2006, and added a boot option to sort the PCI device lists (both of them) in a breadth-first manner to help remain compatible with the 2.4 order, if needed for any reason. This option is not going away, as some systems rely on them. This patch removes the sorting of the internal PCI device list in "BIOS" mode, as it's not needed at all anymore, and hasn't for many years. I've also removed the PCI flags for this from some other arches that for some reason defined them, but never used them. This should not change the ordering of any drivers or device probing. [1] The old-style pci_get_device and pci_find_device() still used this sorting order, but there are very few drivers that use these functions, as they are deprecated for use in this manner. If for some reason, a driver rely on the order and uses these functions, the breadth-first boot option will resolve any problem. Cc: Matt Domsch Signed-off-by: Greg Kroah-Hartman --- Documentation/kernel-parameters.txt | 4 ---- 1 file changed, 4 deletions(-) (limited to 'Documentation/kernel-parameters.txt') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 4b0f1ae31a4c..e30d8fe4e4b1 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1461,10 +1461,6 @@ and is between 256 and 4096 characters. It is defined in the file nomsi [MSI] If the PCI_MSI kernel config parameter is enabled, this kernel boot option can be used to disable the use of MSI interrupts system-wide. - nosort [X86-32] Don't sort PCI devices according to - order given by the PCI BIOS. This sorting is - done to get a device order compatible with - older kernels. biosirq [X86-32] Use PCI BIOS calls to get the interrupt routing table. These calls are known to be buggy on several machines and they hang the machine -- cgit v1.2.2 From 5e0d2a6fc094a9b5047998deefeb1254c66856ee Mon Sep 17 00:00:00 2001 From: mark gross Date: Tue, 4 Mar 2008 15:22:08 -0800 Subject: PCI: iommu: iotlb flushing 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: Mark Gross Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- Documentation/kernel-parameters.txt | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'Documentation/kernel-parameters.txt') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index e30d8fe4e4b1..f7492cd10093 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -847,6 +847,10 @@ and is between 256 and 4096 characters. It is defined in the file than 32 bit addressing. The default is to look for translation below 32 bit and if not available then look in the higher range. + strict [Default Off] + With this option on every unmap_single operation will + result in a hardware IOTLB flush operation as opposed + to batching them for performance. io_delay= [X86-32,X86-64] I/O delay method 0x80 -- cgit v1.2.2