is vfs.lookup_shared unsafe in 7.3?

[Ivan Voras]

On 09/13/10 22:57, cronfy wrote:
> Hello,
>
> Trying to overtake high server load (sudden peaks of 15%us/85%sy, LA>
> 40, very slow lstat() at these moments, looks like some kind of lock
> contention) I enabled vfs.lookup_shared=1 on two servers today. One is
> FreeBSD-7.3 kernel csup'ed and built Sep  9 2010 and other is
> FreeBSD-7.3 csup'ed and built Jul 16 2010.

The important think you missed is *where* is the supposed lock 
contention. If you have lots of processes in "ufs" state, there are 
other things that can help you, such as increasing vfs.ufs.dirhash_maxmem.