Question about 4.2 swap space and pstat -s

[Robert W. Scheifler]

We "fixed" this problem by adding another variable, dmlim, to go between
dmmin and dmmax, and do the swap chunk doubling only up to dmlim instead
of dmmax.  Of course, to get a reasonable size address space you may also
have to increase NDMAP, and this may in turn force you to increase UPAGES.
For example, in order to get reasonable use out of our tiny RK07 swap
partition, we defined DMMIN=32, DMMAX=256, NDMAP=65, and UPAGES=12.
By choosing DMLIM to be 64, 128, or 256, we get 2Mb, 4Mb, or 8Mb spaces,
with increasing fragmentation costs, but still less than vanilla 4.2.
My timings when we first did this showed that such changes made no
noticeable difference in performance, but allowed us to run many more
processes.

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