Date: Mon, 9 Nov 1998 19:59:34 -0500 (EST) From: Brian Feldman <green@unixhelp.org> To: John Fieber <jfieber@indiana.edu> Cc: garman@earthling.net, current@FreeBSD.ORG, julian@whistle.com, wollman@khavrinen.lcs.mit.edu Subject: Re: The infamous dying daemons bug Message-ID: <Pine.BSF.4.05.9811091953110.26160-100000@janus.syracuse.net> In-Reply-To: <Pine.BSF.4.05.9811090932230.462-100000@fallout.campusview.indiana.edu>
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On Mon, 9 Nov 1998, John Fieber wrote:
> On Sun, 8 Nov 1998, Brian Feldman wrote:
>
> > Device 1K-blocks Used Avail Capacity Type
> > /dev/wd0s1b 102400 12300 89972 12% Interleaved
> > /dev/wd1s1b 102400 12408 89864 12% Interleaved
> > Total 204544 24708 179836 12%
> > This is normal usage after
> > swap_pager: suggest more swap space: 157 MB
> > swap_pager: out of swap space
> > pid 5795 (memory), uid 1000, was killed: out of swap space
>
> I don't think this illustrates bug we are trying to smoke out
> though. This is showing the "memory" process as being killed,
> presumably because it went overboard on memory consumption.
>
> The dying daemon bug seems to manifists itself in the death of
The point of "memory" is to eat up ram. Watch:
#include <stdio.h>
#define SIZE 1024
void
main(void) {
int count, yep = 0;
void *stfu[102400];
for (count = 0; count < 102400; count++) {
if((stfu[count] = malloc(SIZE)) != (void *) NULL) {
printf("%p (%i) malloc'd\n", stfu[count], count);
bzero(stfu[count], SIZE);
yep++;
}
else
break;
}
for (count = 0; count < yep; count++) {
free(stfu[count]);
printf("%i free'd\n", count);
}
if (yep != 102400) {
printf("mallocs failed at %i", yep);
exit (1);
}
else
exit (0);
}
> innocent bystander
> processes and usually by a signal 11, not by
> "out of swap space". Note these two observations:
The point of the memory starvation was to _bring_up_ things like this.
Indeed, after the memory starvation had occurred, no processes ata ll were
killed.
>
> Date: Sun, 8 Nov 1998 15:26:48 -0800 (PST)
> From: Julian Elischer <julian@whistle.com>
> Message-ID: <Pine.BSF.3.95.981108152353.12341D-100000@current1.whistle.com>
>
> It's been a while since we looked at it closely but it appeared
> that a page of useful memeory was suddenly unmapped from the
> process.
>
> Date: Sun, 8 Nov 1998 23:17:00 -0500 (EST)
> From: Garrett Wollman <wollman@khavrinen.lcs.mit.edu>
> Message-Id: <199811090417.XAA13563@khavrinen.lcs.mit.edu>
>
> It seems, so far as I was able to characterize, to happen to
> daemons which are *swapped out* at the time of the memory
> shortage. If it's active enough to still be in core, it doesn't
> get spammed.
>
> -john
According to these e-mails, I have been attempting the same scenarios,
but without the same effects.
Cheers,
Brian Feldman
>
>
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