2.0.31-pre7 swap-used wrap-around

Westley Weimer (weimer@merentha.resnet.cornell.edu)
Tue, 26 Aug 1997 18:21:12 -0400 (EDT)


Under 2.0.31-pre7 with the CONFIG_FREE_PAGE_CACHE, QNX 2.0.31-pre6-1 and
raid145-0.36.3-2.0.30 patches, out of the blue while running top I noticed
that I seemed to be using a *lot* of swap space. This is a pentium-100 with
no history of hardware or memory problems.

$ cat /proc/meminfo
total: used: free: shared: buffers: cached:
Mem: 31707136 30621696 1085440 8925184 5865472 10928128
Swap: 111017984 4292739072 113246208
MemTotal: 30964 kB
MemFree: 1060 kB
MemShared: 8716 kB
Buffers: 5728 kB
Cached: 10672 kB
SwapTotal: 108416 kB
SwapFree: 110592 kB

** Note "swap-used" = 4,292,739,072 = 2^32 - 2172k (exactly).

$ cat /etc/fstab
# <file system> <mount point> <type> <options> <dump> <pass>
/dev/sdc1 / ext2 defaults 0 1
/dev/sdc2 none swap sw,pri=1 0 0
/dev/sda2 none swap sw,pri=1 0 0
/dev/md0 /raid ext2 defaults 0 1
...
Where sdc2 and sda2 are both working fine and add up to the 111017984 total
figure seen above.

The system still runs fine (go Linus!) and apparently even continues to
swap. I believe I know how I triggered the problem: while playing with fonts
in the GIMP (gnu image manipulation tool) selecting a new font would
occasionally cause the system to almost grind to a halt. X interactive
performance dropped to nothing (the mouse stopped moving) and the disk drive
access light flashed intermittently, but after ~90 seconds everything
returned to normal. Nothing crashed, so I ignored it. Nothing in the logs.

Everything is (and was) at nice 0 (aside from kswapd's -20 default and a
nice 18 rc5 client).

If this is the symptom of a well understood problem that has been previously
discussed to death, my apologies. :-) If anyone is interested in looking into
this I'd be happy to try to repeat it with, say, a stock 2.0.31-pre7. If
anyone would like more information (like the whole kernel configuration
or something) I'd be happy to provide it.

Thanks and good luck!

-Wes Weimer
wrw3@cornell.edu