vfs.lookup_shared

[Kris Kennaway]

On Fri, May 23, 2008 at 05:16:16PM -1000, Jeff Roberson wrote:
> On Fri, 23 May 2008, Xin LI wrote:
> 
> >-----BEGIN PGP SIGNED MESSAGE-----
> >Hash: SHA1
> >
> >Hi,
> >
> >Is there any reason behind we don't have vfs.lookup_shared enabled by
> >default?
> 
> We have discussed enabling it by default once the ffs shared lookup 
> support is complete.  Unfortunately ffs is still not 100% reliable.  I 
> want to verify that it's an ffs problem and not a problem with the vfs 
> generic code which would effect all filesystems before we enable it by 
> default.

Also, until Attilio's recent lockmgr work, shared lockmgr locks were
starving exclusive lockmgr lock requests, leading to performance
problems on some workloads with the only filesystem that supported
shared locking (NFS).  This is now fixed though.

Kris

--
In God we Trust -- all others must submit an X.509 certificate.
    -- Charles Forsythe <forsythe at alum.mit.edu>