Freeing vnodes.

[Stephan Uphoff]

On Mon, 2005-03-14 at 21:38, Jeff Roberson wrote:
> I have a patch at http://www.chesapeake.net/~jroberson/freevnodes.diff
> that allows us to start reclaiming vnodes from the free list and release
> their memory.  It also changes the semantics of wantfreevnodes, and makes
> getnewvnode() much prettier.
> 
> The changes attempt to keep some number of vnodes, currently 2.5% of
> desiredvnodes, that are free in memory.  Free vnodes are vnodes which
> have no references or pages in memory.  For example, if an application
> simply stat's a vnode, it will end up on the free list at the end of the
> operation.  The algorithm that is currently in place will immediately
> recycle these vnodes once there is enough pressure, which will cause us to
> do a full lookup and reread the inode, etc. as soon as it is stat'd again.
> 
> This also removes the recycling from the getnewvnode() path.  Instead, it
> is done by a new helper function that is called from vnlru_proc().  This
> function just frees vnodes from the head of the list until we reach our
> wantfreevnodes target.
> 
> I haven't perf tested this yet, but I have a box that is doing a
> buildworld with a fairly constant freevnodes count which shows that vnodes
> are actually being uma_zfree'd.
> 
> Comments?  Anyone willing to do some perf tests for me?
> 
> Thanks,
> Jeff

Just looked at the raw diff and might have missed it -  how are the
parent directory "name" cache entries ( vnode fields v_dd, v_ddid)
handled?

Thanks,
Stephan