Guy Helmer wrote:
Gergely CZUCZY wrote:
Hello,
I'm trying to set up a qemu with 4G memory to the host system
on a 7-BETA2, and I've hit some kind of limit in freebsd.
When i give more then ~2000MB of memory to qemu, it returns
an after trying to mmap() it, saying "Could not map physical memory".
At the end of mmap(2) there's a note saying:
" The len argument is limited to the maximum file size or
available user-
land address space. Files may not be able to be made more than
1TB large
on 32 bit systems due to file systems restrictions and bugs, but
address
space is far more restrictive. Larger files may be possible on
64 bit
systems."
I guess I've found this limit. I've tried to check a few sysctls but
I wasn't
able to find the one effecting this limit.
Could someone point me into the right direction in increasing the
maximum
mmap-able size?
If you are using the 32-bit i386 system, then you could be limited by
a couple of things, the kern.maxdsiz loader tunable or the datasize
limit are likely. On i386, I believe 1073741824 (1G) is the default
maxdsiz. With 4GB of RAM, I think you ought to be able to double
kern.maxdsiz in /boot/loader.conf.
Sorry to respond to my own posting: I just realized that the length
value for mmap(), a size_t value, will become negative on i386 for
values 2GB and over. That might be the source of your trouble.
Guy
--
Guy Helmer, Ph.D.
Chief System Architect
Palisade Systems, Inc.
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