More shared memory than physical memory.

Peter Ekberg (peda@pulkan.rydnet.lysator.liu.se)
Tue, 30 Apr 1996 10:25:14 +0200

Hello,
when I boot (1.3.9[67]), start X and the first thing I do in X
is to check the available memory, the amount of shared memory
reported by /proc/meminfo is greater than the amount of physical
memory I have. After a couple of minutes of operation there seems
to happen something that fixes this, and the reported amount is
more sensible. I'm not sure, but it could be that the amount of
reported shared memory isn't correct until the first a.out binary
is executed.

I also noted this behaviour when I first upgraded to libc 5.3.12
and killed and restarted all processes (except init, kflushd and
kswapd). This was with 1.3.75. I havn't tried any kernels between
75 and 96.

All of the mentioned kernels run/ran with kerneld. ELF compiled
in and a.out as an autoloading module.

(BTW, I had 1.3.75 up for little short of 4 weeks before I decided
to try 1.3.96. Great! And it would have been 6 weeks if some moron
hadn't turned off the power.)

__________________________________
Peter Ekberg
peda@lysator.liu.se
http://www.lysator.liu.se/~peda/

And the traces (1.3.97):

pulkan:~$ cat /proc/meminfo
total: used: free: shared: buffers: cached:
Mem: 15446016 15278080 167936 19824640 143360 4972544
Swap: 36638720 303104 36335616
MemTotal: 15084 kB
MemFree: 164 kB
MemShared: 19360 kB
Buffers: 140 kB
Cached: 4856 kB
SwapTotal: 35780 kB
SwapFree: 35484 kB

pulkan:~$ ps auxwww
USER PID %CPU %MEM SIZE RSS TTY STAT START TIME COMMAND
#65534 156 0.0 1.2 756 188 ? S 09:26 0:00 bin/spider_hostname
#65534 158 0.0 1.2 756 188 ? S 09:26 0:00 bin/spider_hostname
bin 70 0.0 2.1 792 320 ? S 09:26 0:00
/usr/sbin/rpc.portmap
peda 149 0.2 5.5 2872 836 ? S 09:26 0:00 xinit -- -auth
/home/peda/.Xauthority vt12
peda 150 0.0 1.5 828 240 ? S 09:26 0:00 ssh-agent xinit --
-auth /home/peda/.Xauthority vt12
peda 157 1.5 6.0 2216 908 ? S 09:26 0:01 fvwm
peda 164 0.3 5.0 2084 756 ? S 09:26 0:00
/usr/lib/X11/fvwm/GoodStuff 7 4 /home/peda/.fvwmrc 0 8
peda 165 0.3 4.3 2012 660 ? S 09:26 0:00
/usr/lib/X11/fvwm/FvwmWinList 9 4 /home/peda/.fvwmrc 0 8
peda 171 0.5 9.1 3268 1376 ? S 09:26 0:00 xload -nolabel
-geometry +0+0
peda 172 0.4 8.7 2960 1320 ? S 09:26 0:00 oclock -geometry
+0+0 -fg red
peda 173 0.6 9.0 3252 1368 ? S 09:26 0:00 xbiff -geometry
+0+0 -file /home/peda/mail/LATEST -shape
peda 174 2.4 6.9 1892 1052 ? S 09:26 0:01 xosview -geometry
+0+0
peda 175 0.4 4.2 1124 636 p0 S 09:27 0:00 -bash
peda 183 0.7 4.3 1128 656 p1 S 09:27 0:00 -bash
peda 197 0.0 2.4 820 368 p1 R 09:28 0:00 ps auxwww
root 1 0.6 2.0 772 308 ? S 09:26 0:00 init [5]

root 2 0.0 0.0 0 0 ? SW 09:26 0:00 (kflushd)
root 3 0.0 0.0 0 0 ? SW< 09:26 0:00 (kswapd)
root 9 0.0 1.6 756 252 ? S 09:26 0:00 update (bdflush)
root 17 0.0 1.8 764 284 ? S 09:26 0:00 /sbin/kerneld
root 31 0.0 2.0 772 308 ? S 09:26 0:00 /usr/sbin/crond
-l10
root 61 0.0 0.0 0 0 ? SW 09:26 0:00 (nfsiod)
root 62 0.0 0.0 0 0 ? SW 09:26 0:00 (nfsiod)
root 63 0.0 0.0 0 0 ? SW 09:26 0:00 (nfsiod)
root 64 0.0 0.0 0 0 ? SW 09:26 0:00 (nfsiod)
root 66 0.3 2.3 784 352 ? S 09:26 0:00 /usr/sbin/syslogd
root 68 0.0 2.0 768 316 ? S 09:26 0:00 /usr/sbin/klogd
root 72 0.1 2.1 776 328 ? S 09:26 0:00 /usr/sbin/inetd
root 74 0.0 2.4 764 376 ? S 09:26 0:00 /usr/sbin/in.rwhod
-prwho -c-
root 76 0.0 2.1 792 320 ? S 09:26 0:00 /usr/sbin/lpd
root 80 0.0 2.6 804 400 ? S 09:26 0:00
/usr/sbin/rpc.mountd
root 82 0.0 2.7 820 412 ? S 09:26 0:00 /usr/sbin/rpc.nfsd
root 85 0.1 3.0 872 464 ? S 09:26 0:00 -d1
-l/var/adm/smblogs/nmbdlog
root 87 0.0 3.8 1004 588 ? S 09:26 0:00 sendmail: accepting
connections
root 96 0.0 2.3 844 352 ? S 09:26 0:00 gpm -t msc
root 97 18.2 2.9 968 444 ? S 09:26 0:19
/usr/local/sbin/sshd
root 99 0.1 3.4 1092 520 ? S 09:26 0:00 sh ./start
root 102 0.0 1.8 764 284 2 S 09:26 0:00 /sbin/agetty 38400
tty2 linux
root 103 0.0 1.8 764 284 3 S 09:26 0:00 /sbin/agetty 38400
tty3 linux
root 104 0.0 1.8 764 284 4 S 09:26 0:00 /sbin/agetty 38400
tty4 linux
root 151 0.0 1.8 764 284 1 S 09:26 0:00 /sbin/agetty 38400
tty1 linux
root 152 6.6 15.5 4448 2348 ? S 09:26 0:06 X :0 -auth
/home/peda/.Xauthority vt12
root 166 1.5 11.2 4028 1704 ? S 09:26 0:01 xterm -C -geometry
90x5+0-0 -ls -j -rw +aw -font fixed -sl 1500 -bg slateblue4 -fg honeydew3 -T
console -n console
root 180 1.1 11.9 3596 1804 ? S 09:27 0:00
/usr/bin/X11/color_xterm -sb -sl 500 -j -ls -fn fixed -T X-term -n X-term
www 148 14.3 8.9 2592 1352 ? S 09:26 0:13 bin/ulpc -m
etc/master.lpc -DSPINNER_VERSION=111 -DSPINNER_B11 -DSPINNER spider
--config-dir=configurations/

And after a couple of minutes:

pulkan:~$ cat /proc/meminfo
total: used: free: shared: buffers: cached:
Mem: 15446016 15065088 380928 12845056 434176 5615616
Swap: 36638720 2015232 34623488
MemTotal: 15084 kB
MemFree: 372 kB
MemShared: 12544 kB
Buffers: 424 kB
Cached: 5484 kB
SwapTotal: 35780 kB
SwapFree: 33812 kB

__________________________________
Peter Ekberg
peda@lysator.liu.se
http://www.lysator.liu.se/~peda/