Maximum ioremap size for ppc arch?

Scott Wood scottwood at
Thu Dec 6 04:50:40 EST 2007

Scott Wood wrote:
> michael.firth at wrote:
>> This seems to leave only 1GB of addressing space for all the
>> physically addressable memory (RAM + ioremapped + registers), while
>> reserving 3GB of space for user processes. The 3GB is presumably
>> mostly unusable on a system without a large amount of swap, as the
>> 1GB limit on memory will prevent much more than that being available
>> for user space.
> Well, it's also useful for sparse mappings, but I agree that the 3/1 
> split is probably suboptimal for most workloads.

Oh, and the 3G user is also useful for accessing highmem, of course.


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