BAT mapping exported to user-space

Linh Dang linh at linhdang.home
Tue Jul 27 04:33:27 EST 2004

Dan Malek <dan at> wrote:

> On Jul 26, 2004, at 1:20 PM, Linh Dang wrote:
>> - has it been discussed/comptemplate/done before?
> Of course.  Use mmap(), either on /dev/mem directly, or more
> preferable through a simple device driver for your ASIC that
> could also do simple system protection.
> Please don't be making such memory mapping kernel
> modifications.  It will only cause future trouble.
> -- Dan

My understanding is:

- mmap(2) uses pages to map the device (my platform doesn't have large page.)
- mapping a large address range (hundreds-of-megabytes) is much more
  efficient with BATs than with pages.

So, do you mean:
        - mmap(2) can use BATs? or
        - the difference in performance is negligible between BATs and
          pages when mapping an address range of 200MBs?

Linh Dang

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