limitiation on memory allocation

Dima Sorkin dima.sorkin at
Mon Mar 12 18:20:57 UTC 2007

 I experimented with the values:

 1) On my machine 'maxusers' doesn't influence the maximum memory
     allowable for allocation for single process.

 2) 'maxdsiz' -  Yes, as long as I keep 'maxdsiz + maxssiz' below physical
     memory size - everything is fine. Single process allocates successfully
     up to 'maxdsiz'.
                When tried to put 'maxdsiz' > phys mem size,
      indeed the system failed to boot, in all modes:
      multiuser, singleuser, safe.

So I derive from here that there is no way to cause a _single process_
on FreeBSD to allocate more than physical memory size (?)

Thank you and regards,

On 3/9/07, Derek Ragona <derek at> wrote:
>  Not all the settings there are tuneable.  In 6.X the allowable memory is
> somewhat automatic based on the max users.  Your kernel is set to 384.  You
> can try changing that.
>  You can also make some kernel settings in:
>  /boot/loader.conf
>  You can see the possible variables to set in:
>  /boot/defaults/loader.conf
>  I think the one variable you may want to change is:
>  kern.maxdsiz="to your actual real memory size"
>  Don't make this larger than the real memory, in my experience that will
> cause the system to not boot properly into multi-user.

>  At 11:06 AM 3/9/2007, Dima Sorkin wrote:
>   On FreeBSD 6.2 i386 with 2GB of physical memory I can't allocate
>   more than 500Mb for my program.

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