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Revision 6a0596583fadd15dca293736114abdea306d3d7c authored by Linus Torvalds on 24 October 2011, 05:08:24 UTC, committed by Linus Torvalds on 24 October 2011, 05:08:24 UTC 
Merge git://git.infradead.org/iommu-2.6
 
* git://git.infradead.org/iommu-2.6:
  intel-iommu: fix superpage support in pfn_to_dma_pte()
  intel-iommu: set iommu_superpage on VM domains to lowest common denominator
  intel-iommu: fix return value of iommu_unmap() API
  MAINTAINERS: Update VT-d entry for drivers/pci -> drivers/iommu move
  intel-iommu: Export a flag indicating that the IOMMU is used for iGFX.
  intel-iommu: Workaround IOTLB hang on Ironlake GPU
  intel-iommu: Fix AB-BA lockdep report
2 parent s 15cc910 + 4399c8b
Raw File
memory.txt 
There are several classic problems related to memory on Linux
systems.

	1) There are some motherboards that will not cache above
	   a certain quantity of memory.  If you have one of these
	   motherboards, your system will be SLOWER, not faster
	   as you add more memory.  Consider exchanging your 
           motherboard.

All of these problems can be addressed with the "mem=XXXM" boot option
(where XXX is the size of RAM to use in megabytes).  
It can also tell Linux to use less memory than is actually installed.
If you use "mem=" on a machine with PCI, consider using "memmap=" to avoid
physical address space collisions.

See the documentation of your boot loader (LILO, grub, loadlin, etc.) about
how to pass options to the kernel.

There are other memory problems which Linux cannot deal with.  Random
corruption of memory is usually a sign of serious hardware trouble.
Try:

	* Reducing memory settings in the BIOS to the most conservative 
          timings.

	* Adding a cooling fan.

	* Not overclocking your CPU.

	* Having the memory tested in a memory tester or exchanged
	  with the vendor. Consider testing it with memtest86 yourself.
	
	* Exchanging your CPU, cache, or motherboard for one that works.
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