Re: [linux-cifs-client] [PATCH] cifs: implement drop_inode superblock op

[Jeff Layton <jlayton@redhat.com>]

On Wed, 26 May 2010 19:19:11 -0400
Scott Lovenberg <scott.lovenberg@gmail.com> wrote:

> 
> >> Any rough idea of performance or memory savings (even in something
> >> artificial like dbench run)?
> >>
> >>      
> > It's more of a memory savings thing. When I mount with -o noserverino
> > and run fsstress on the mount, I'd regularly see the size of the
> > cifs_inode_cache hit 60M or more (on a client with 1G RAM). With this
> > patch in place, it rarely goes over 2M in size.
> >
> > Eventually, memory pressure will force the size to go down, but if we
> > know that they'll never be used again (which is the case with
> > noserverino), it's better to go ahead and just free them.
> >
> >    
> I take it this overrides the behavior of the vfs_cache_pressure before 
> the memory pressure makes reclaiming cache necessary?

Not exactly. vfs_cache_pressure just governs the way in which the VM
subsystem will attempt to free memory when it needs it by changing the
preference for flushing inode and dentry caches.

This patch just aims to delete inodes that we know will never be used
again as soon as their refcount drops to 0.

-- 
Jeff Layton <jlayton@redhat.com>