limitiation on memory allocation

Dima Sorkin dima.sorkin at
Sat Mar 10 16:59:30 UTC 2007

 I've read some pages about 'kern.maxusers', 'kern.maxdsize'.
I have questions:
 After I reduce 'maxusers' to some reasonable amount for that computer (say 10),
and enlarge 'maxdsize', will a user process be able to allocate
arrays that are considerably bigger than the physical memory size ?
This is what I really need. I run processes in which it can come to
1.5x-2x ratio.

2) Following the
 Should I put   maxdsize == phys mem size, or should I put it lower
(by how much) ?

3) On Intel pentium 4 machine with 2GB phys memory,
during installation where almost all options were taken as defaults,
should I worry that kernel is not configured to use PAE ?
Installation program by default allocated 4GB swap,
so totally it is 6GB. How do I check this ?


On 3/9/07, Derek Ragona  wrote:
>  Dima,
>  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.
>          -Derek
>   On FreeBSD 6.2 i386 with 2GB of physical memory I can't allocate
>   more than 500Mb for my program.

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