On Thu, 12 Apr 2001 16:12:55 BST, Alan Cox said:
> > I've seen the same scenario about 2-3 times a week. kswapd and one or
> > more processes all CPU bound, totalling to 100%. I've had 'esdplay' hung
> > on several occasions, and 2-3 times it's been xscreensaver (3.29) hung.
> > The 'hung' processes are consistently immune to kill -9, even as root, which
> > indicates to me that they're hung inside a kernel call or something.
>
> Do you have > 800Mb of RAM ?
256M of RAM, 256M of swap.
Here's /proc/meminfo as I type:
[~]3 cat /proc/meminfo
total: used: free: shared: buffers: cached:
Mem: 260276224 246419456 13856768 0 8347648 75317248
Swap: 271392768 58589184 212803584
MemTotal: 254176 kB
MemFree: 13532 kB
MemShared: 0 kB
Buffers: 8152 kB
Cached: 73552 kB
Active: 49716 kB
Inact_dirty: 28800 kB
Inact_clean: 3188 kB
Inact_target: 212 kB
HighTotal: 0 kB
HighFree: 0 kB
LowTotal: 254176 kB
LowFree: 13532 kB
SwapTotal: 265032 kB
SwapFree: 207816 kB
[~]3
> > would explain the high context-switch rate. I'm not clear on how kswapd
> > can end up getting stuck and failing to free up something - unless it ends
> > up calling __alloc_pages itself indirectly and the PF_MEMALLOC bit isn't
> > enough to get it the memory it needs, causing a deadlock/loop between
> > kswapd and __alloc_pages/wakeup_kswapd().
>
> bounce buffers for one
It's a Dell Optiplex GX110, using IDE. Grepping for 'bounce buffer' in
the source shows most hits in the SCSI code, and nothing obviously jumping
out at me...
<just speculating> Is it possible that i810_audio.c is to blame? I'm looking
at alloc_dmabuf() in there, and it tries to grab a big chunk of memory
for a DMA buffer (starting at order-4), which probably explains my __alloc_pages
messages. In addition, I run Enlightenment with audio enabled - so it's
quite possible that xscreensaver will generate a 'click' sound when it
pops up its dialog window - again tossing us into i810_audio. (scenario
there - mouse event happens while screen locked, xscreensaver wakes up and
starts mapping a window - E plays the sound, hosing the i810_audio driver,
and then when xscreensaver gets the CPU back, its next call for a page
gets wedged up.
Would it be worth applying Ed Tomlinson's icache/dcache patches and seeing
if that helps?
--
Valdis Kletnieks
Operating Systems Analyst
Virginia Tech
PGP signature
