Hello,
Some time ago, during the discussion about module efficiency,
Dan Malek wrote the following:
> The other thing people probably don't realize is the added overhead
> of using modules. They are placed in dynamically allocated memory,
> wasting memory space and causing addtional MMU overhead on processors
> where you really want to minimize such things. When compiled into the
> kernel and covered with a large page mapping, you are likely to see
> lower interrupt latencies and less jitter, along with a more compact
> memory footprint.
I was looking at TLB entries on my 405GP-based system running 2.4.17-based
kernel by executing "tlb 0 63" command in BDI-2000 and could not see any
big page mappings. All page entries were 4K in size (and I could see many
that were clearly covering portions of kernel code)
My questions are:
a) Does the abovementioned quote apply to 4xx CPUs
b) If yes, where can I get the patches
c) If no, how difficult might it be to do the modification
d) Are there provisions in Linux VM to use variable-sized pages to cover
big contiguous memory regions in order to reduce TLB reloading.
Thanks,
Vladimir
** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
