Incorrect physical memory when hw.physmem is set

Mohd Fahadullah fahadullah at
Thu Sep 25 02:46:03 UTC 2008


There is a peculiar case when physical memory limit is set through
hw.physmem and Freebsd sets usable memory to much lesser value.
In cases with 8 GB of RAM where the physical memory address space is
remapped above 4 GB and if we set hw.physmem to 4 GB then Freebsd actually
skips the segments remapped above 4 GB. So we end up with much less memory
than 4 GB depending upon the memory hole in the top of 4 GB address space.

I would like to know if someone else came across the same issue.

Thank you,


More information about the freebsd-questions mailing list