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Newsgroups: comp.os.386bsd.questions
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From: root@wanderer.nsi.nasa.gov (Michael C. Newell)
Subject: Virtual memory problem
Message-ID: <1993Jun24.015842.21623@news.arc.nasa.gov>
Sender: usenet@news.arc.nasa.gov
Organization: NASA Ames Research Center, Moffett Field, CA
Date: Thu, 24 Jun 1993 01:58:42 GMT
Lines: 40
I've been trying to compile some of the Xview utility
programs (notably textedit), and they include LOTS of
header files. They bomb out with an error, "insufficient
virtual memory". This seemed odd to me because I have
16Mb of memory on the machine and a 20Mb swap partition
(I know it is recommended to have 2xRealMemory for swap,
but I don't have the space right now...) In fact, if I
add another 88Mb volume that is ENTIRELY swap, I still
get the error.
So I wrote a simple C program that went into an infinte
loop doing mallocs for 1K blocks of memory. It was able
to get 3072 [interesting number...] before it ran out
of VM. The drive with the 88Mb swap partition rattled
around during this process, so I assume space was being
allocated on it. The vmstat command showed about 1K
of "free" memory; and some amount (I don't remember now
how much) of "avl" memory.
In rooting around the malloc related code I came across
the constant "DFLDSIZ" in "/sys/i386/include/vmparam.h".
It is supposed to be the "initial data size limit", and
was set to "6*1024*1024", or 6Mb. I changed this to
"16*1024*1024" and rebuilt the kernel. The little C
program now was able to allocate 8192 1K blocks. This
was enough to get past the "insufficient virtual memory"
errors [unfortunately others followed... :{(]
So my question is, "Why is this happening?" Why can't
I allocate some reasonably close-to-16Mb amount of
virtual memory? Is "DFLDSIZ" really the MAXIMUM amount
(there is another constant "MAXDSIZ" set to 32Mb which
would seem to perform that function.)
??
Thanks,
Mike Newell
NASA Advanced Network Applications Group