Re: dentry_cache using up all my zone normal memory -- also seen on 2.6.14-rc2

[Dipankar Sarma <dipankar@in.ibm.com>]

On Tue, Oct 04, 2005 at 02:02:39PM -0600, Christopher Friesen wrote:
> Dipankar Sarma wrote:
> 
> >Since then, I have done some testing myself, but I can't reproduce
> >this problem in two of my systems - x86 and x86_64. I ran rename14
> >in a loop too, but after exhausting a lot of free memory, dcache
> >does get shrunk and I don't see dentries stuck in RCU queues at all.
> >I tried UP kernel too.
> 
> I've only managed to reproduce it on a UP system with HIGHMEM.
> 
> >So, there must be something else in your system that I
> >am missing in my setup. Could you please mail me your .config ?
> 
> Sent privately.

Chris pointed out privately that the LTP rename14 test always
creates a directory in /tmp and runs from there (hidden
in an ltp library call tst_tmpdir()), not from the current
working directory. So, my tests weren't really running on
tmpfs. So, I commented out the tst_tmpdir() call in the test
forcing it to run on tmpfs and immediately I got the following
errors -

llm22:/test # ./rename14
Bad page state at prep_new_page (in process 'rename14', page ffff810008000000)
flags:0x4000000000000090 mapping:0000000000000000 mapcount:0 count:0
Backtrace:
Trying to fix it up, but a reboot is needed
Bad page state at prep_new_page (in process 'syslogd', page ffff8100080002a0)
flags:0x4000000000000000 mapping:0000000000000000 mapcount:0 count:-26471
Backtrace:
Trying to fix it up, but a reboot is needed

Bad page state at prep_new_page (in process 'rename14', page ffff810008001538)

llm22 kernel: Bflags:0x4000000000000000 mapping:0000005500005555 mapcount:0 count:0
ad page state atBacktrace:
 prep_new_page (Trying to fix it up, but a reboot is needed
in process 'renaBad page state at prep_new_page (in process 'rename14', page ffff810008002aa8)
me14', page ffffflags:0x4000000000000090 mapping:0000000000000000 mapcount:0 count:0
810008000000)
Backtrace:
Trying to fix it up, but a reboot is needed

Message from syslogd@llm22 at Tue Oct  4 19:41:42 2005 ...
llm22 kernel: fBad page state at prep_new_page (in process 'rename14', page ffff810008005550)
lags:0x400000000flags:0x4000005500009090 mapping:0000000000000000 mapcount:0 count:0
0000090 mapping:Backtrace:
0000000000000000Trying to fix it up, but a reboot is needed
 mapcount:0 count:0

Andi, does this look any familiar ? This is on a 2-CPU x86_64 system
running 2.6.14-rc3 (UP kernel though).

Thanks
Dipankar