Re: 2.5.42-mm2 hangs system

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

On Wed, Oct 16, 2002 at 08:59:08PM +0200, Henrik Storner wrote:
> well you hit the nail right on the head there.
> 
> I've just been running the 2.5.42-mm2 kernel except for the dcache_rcu
> patch for a full hour, and I was unable to reproduce the hangs that I
> saw with the full -mm2 patch installed. Did two full kernel builds
> while reading some mail and doing other stuff - no problems what so
> ever.
> 
> Just to be sure, I re-applied the dcache_rcu patch, rebuilt the
> kernel, booted with the kernel containing dcache_rcu patch,
> and the system died within a few minutes.
> 
> So it is definitely something in the dcache_rcu patch that does it.

Well, I am not quite sure of this yet. Maneesh pointed out this earlier -
In this machine with 2.5.42-mm2 and no dcache_rcu, (with your .config), 
we see  this -

[root@llm04 dbench]# df
Filesystem           1k-blocks      Used Available Use% Mounted on
/dev/sda6              1004024    461168    491852  49% /
/dev/sda1               505605     38348    441153   8% /boot
/dev/sda5              2514172   1791560    594900  76% /usr
none                    257532         0    257532   0% /dev/shm
/dev/sdb5              6324896     23996   5979604   1% /mnt/sdb5
llm04:/mnt/sdb5        6324896     23968   5979616   1% /mnt/sdc1
/dev/sda2              9068648   3993040   4614948  47% /home
[root@llm04 dbench]# pwd
/mnt/sdc1/dbench
root@llm04 dbench]# ./dbench 4
4 clients started
..........................................................................................................................................rmdir CLIENTS/CLIENT2/~DMTMP/WORDPRO failed (Directory not empty)
rmdir CLIENTS/CLIENT2/~DMTMP/PARADOX failed (Directory not empty)
rmdir CLIENTS/CLIENT2/~DMTMP failed (Directory not empty)
+.......rmdir CLIENTS/CLIENT0/~DMTMP/WORDPRO failed (Directory not empty)
rmdir CLIENTS/CLIENT0/~DMTMP/PARADOX failed (Directory not empty)
.rmdir CLIENTS/CLIENT0/~DMTMP failed (Directory not empty)
+.rmdir CLIENTS/CLIENT3/~DMTMP/WORDPRO failed (Directory not empty)
rmdir CLIENTS/CLIENT3/~DMTMP/PARADOX failed (Directory not empty)
rmdir CLIENTS/CLIENT3/~DMTMP failed (Directory not empty)
+.rmdir CLIENTS/CLIENT1/~DMTMP/WORDPRO failed (Directory not empty)
rmdir CLIENTS/CLIENT1/~DMTMP/PARADOX failed (Directory not empty)
rmdir CLIENTS/CLIENT1/~DMTMP failed (Directory not empty)
+****
Throughput 36.6733 MB/sec (NB=45.8417 MB/sec  366.733 MBit/sec)

This needs more investigation. I would be really supprised if dcache_rcu
has any effect on UP code.

Thanks
-- 
Dipankar Sarma  <dipankar@in.ibm.com> http://lse.sourceforge.net
Linux Technology Center, IBM Software Lab, Bangalore, India.
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