Driver memory allocation

[Julian Elischer]

On 12/15/10 4:33 AM, Dr. Baud wrote:
>      Is there a cap on the amount of memory a driver (via bus_dmamem_alloc) can
> allocate, other than the obvious physical memory limit minus the memory already
> allocated?
>
well it has to fit into the kernel virtual space too.
this is quite limited on x86 though  for amd64 it is a lot bigger.

I have seen drivers on amd64 setting asside a couple of GB (but you need
a new kernel that has the kernel virtual space expanded). The kernel can
make use of the direct-map space for driver allocation too.

>      Dr.
>
>
>
>
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