:One of our developers tested with snapshots; it looks like the DMA
:reserve commit is the one that made DF no longer run w/ 48MB. That
:makes sense, as 16MB of physical memory is locked up by that commit.
:You should be able to boot with a loader variable set to reserve less
:physical memory.
:
:We someday need a better physmem allocator; the 16MB reserve is a good
:step, but a low-fragmentation allocator would be better.
:
:-- vs;
It should be reserving less space on low-memory machines.
if (vm_dma_reserved == 0) {
vm_dma_reserved = 16 * 1024 * 1024; /* 16MB */
if (vm_dma_reserved > total / 16)
vm_dma_reserved = total / 16;
}
We could try zeroing it. Or perhaps the calculation is wrong...
maybe it should be basing the test on 'npages' instead of 'total'.
e.g. ((vm_paddr_t)npages * PAGE_SIZE / 16) instead of (total / 16).
However, we really don't support machines with so little memory,
even if the thing manages to boot. If a simple change makes it work
then fine, but otherwise I'm skeptical of the value.
This variable is a tunable. Try setting 'vm.dma_reserved=0' in the
boot loader.
-Matt
Matthew Dillon
<dil...@backplane.com>
