Date: Mon, 5 Jun 1995 14:30:41 -0500 (CDT) From: Joe Greco <jgreco@brasil.moneng.mei.com> To: davidg@root.com Cc: hackers@freebsd.org Subject: Re: 2.0.5-A: Very disheartening? Message-ID: <199506051930.OAA07820@brasil.moneng.mei.com> In-Reply-To: <199506051743.KAA07302@corbin.Root.COM> from "David Greenman" at Jun 5, 95 10:43:40 am
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> Considering the kind of extensive testing that I and others have been doing
> over the last 2 months, and the relative few changes that have been made to
> the kernel (especially in areas that might make a difference in the kind of
> problems that you're seeing), I must conclude that the problem is specific to
> both your configuration and the way that the installation works. I think there
> is some kind of quirk in the kernel gziping and/or compressed MFS that is
> being used in the install process that is causing the problem.
> I am interested in working with you and others to diagnose and fix the
> problem, but I have very little to go by at the moment. Any information that
> you can provide about your hardware and the steps you took (such as disabling
> or not disabling devices in userconfig, etc.), is escential.
Going back to the message I just sent a few minutes ago:
Well it turns out the test program I hurriedly grabbed was actually meant to
test something somewhat different under Solaris. But it seems to me that a
compile should not crash a box? Even if the program is sadistic. :-)
I dropped a hard disk in and proceeded to get:
wye /kernel: vnode_pager_output: attempt to write meta-data!!! -- 0xfffe9000(ff)
and an understandably long period of thrashing while it compiled the
attached 1500 bytes of code :-)
Next I mounted the NFS /root and did the compile.. no prob
/tmp and /var/tmp.. no prob
/usr... no prob
and it looks like just about the only thing it's doing locally is... swap.
HMMMM!
Well, that is fascinating. It suggests an experiment that I will try in a
bit...
... Joe
-------------------------------------------------------------------------------
Joe Greco - Systems Software Engineer, UNIX/Network Hacker, Etc. 414/362-3617
Marquette Electronics, Inc. - R&D - Milwaukee, WI jgreco@mei.com
#include <stdio.h>
#include <unistd.h>
#include <malloc.h>
#include <sys/types.h>
#define MEGABYTES 16
#define BYTES MEGABYTES * 1024 * 1024 / sizeof(int)
static int array[MEGABYTES * 1024 * 1024 / sizeof(int) + 8192] = {
0
};
int tweak = 0;
void flipThroughPages(char *addr, unsigned long bytes)
{
register int pagesize = 4096;
register int pages = bytes / pagesize;
register char x;
if (tweak & 1) {
pagesize = 256;
}
while (pages--) {
*addr = 0x01;
addr += pagesize;
}
}
int inCorePages(char *addr, unsigned long bytes, char *tag)
{
int i, incore = 0;
register int pagesize = 4096;
register int pages = bytes / pagesize;
char *x;
if (! (x = (char *)malloc(pages + 1))) {
fprintf(stderr, "out of memory in inCorePages?\n");
return(-1);
}
if (mincore((caddr_t) addr, (size_t) bytes, x) < 0) {
perror("mincore");
free((char *)x);
return(-1);
}
for (i = 0; i < pages; i++) {
incore += *(x + i) & 0x01;
}
free((char *)x);
printf("%s: inCorePages: %d of %d\n", tag, incore, pages);
return(0);
}
int main(int argc, char *argv[])
{
char *ptr;
int pagesize = 4096;
if (argc == 2) {
tweak = atoi(argv[1]);
}
/* page align the array */
ptr = (char *)((((int)array / pagesize) + 1) * pagesize);
inCorePages((char *)ptr, BYTES, "before running");
flipThroughPages((char *)ptr, BYTES);
inCorePages((char *)ptr, BYTES, "after flip");
while (1) {
sleep(60);
inCorePages((char *)ptr, BYTES, "after flip and sleep");
}
}
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