Re: vnlur_proc lockups under high disk I/O

[Gary Allan <dragonfly@xxxxxxxxxxxxxxx>]

Matthew Dillon wrote:
> :I've attached the dmesg output. I'm running memory and disk diagnostics 
> :as it's strange that its only just started. (I haven't run a buildworld 
> :in a week but only noticed the problem yesterday.)
> :
> :Extracting a large tar file while the CPU is under load nearly always 
> :triggers the problem. It's as if disk IO operations take longer and 
> :longer until they eventually time out locking the machine. You can watch 
> :the disk activity led go from constant to briefly flashing at increasing 
> :intervals.
> :
> :Buildworlds also gradually slow to a crawl but so far haven't resulted 
> :in the vnlru_proc errors.
> :
> :The first time it happened I was running "make -j 4 buildworld" on the 
> :console and extracting the pkgsrc tarball to /usr/pkgsrc via a SSH session.
> :
> :Regards
> :
> :Gary
>
>     What is likely happening is that the recycler is trying to flush out vnodes
>     related to things other then the hard drive, and one of those things is 
>     causing it to stall.
>
>     Observe your other mounts carefully.  What other mounts do you have?
>
> 							-Matt

I have a semi-production machine running stable from a few months ago. 
The vnode related sysctl values on this machine are;

kern.maxvnodes = 36053
kern.minvnodes = 9008

However on the machine I'm having problems with they are; (current stable)

kern.maxvnodes = 16754
kern.minvnodes = 4188

I've added the previous settings to /etc/sysctl.conf and the problems 
have not reoccurred. I can now run "cd /usr/pkgsrc && cvs -q update -dP" 
without problems, previously this would result in a lockup without failure.

I only have standard mounts and am only working within /usr.

df
Filesystem  1K-blocks   Used    Avail Capacity  Mounted on
/dev/ad2s1a    254063  47193   186545    20%    /
/dev/ad2s1d    254063    307   233431     0%    /var
/dev/ad2s1e    254063      8   233730     0%    /tmp
/dev/ad2s1f  36606155 346959 33330704     1%    /usr
procfs              4      4        0   100%    /proc

Do you still want a kernel core?

Regards

Gary