Setting MAXDSIZ, MAXSSIZ, DFLDSIZ via kernel OIDs?

Dan Nelson dnelson at
Thu Feb 24 20:07:08 GMT 2005

In the last episode (Feb 24), O. Hartmann said:
> Due to runtime problems of several F77 code based scientific software
> I increased possible data segment size and stack by the shown values.
> options         MAXDSIZ=(2048UL*1024*1024)
> options         MAXSSIZ=(1024UL*1024*1024)
> options         DFLDSIZ=(1024UL*1024*1024)
> These changes implies building a new kernel and I would like to know
> how I can set these parameters via kern.l OIDs (in
> loader.conf.local).

I'm sure it's documented somewhere but I find it easier to grep for the
word TUNABLE in the kernel source :) Found these in subr_param.c:

    TUNABLE_QUAD_FETCH("kern.maxdsiz", &maxdsiz);
    TUNABLE_QUAD_FETCH("kern.dfldsiz", &dfldsiz);
    TUNABLE_QUAD_FETCH("kern.maxssiz", &maxssiz);

	Dan Nelson
	dnelson at

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