Re: [6/6]: jenkins hash for neigh

["David S. Miller" <davem@xxxxxxxxxxxxx>]

On Sat, 2 Oct 2004 17:50:51 +1000
Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> wrote:

> On Mon, Sep 27, 2004 at 11:15:20AM -0700, David S. Miller wrote:
> > On Mon, 27 Sep 2004 21:48:33 +1000
> > Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> wrote:
> > 
> > > > -       if (tbl->entries > (tbl->hash_mask + 1))
> > > > +       if (tbl->entries > (tbl->hash_mask + 1)) {
> > > > +               write_lock_bh(&tbl->lock);
> > > >                 neigh_hash_grow(tbl, (tbl->hash_mask + 1) << 1);
> > > > +               write_unlock_bh(&tbl->lock);
> > > > +       }
> > > 
> > > The locking should be outside the if block as otherwise you may grow
> > > unnecessarily or grow into the same size :)
> > 
> > I'm not going to do that, because then we're grabbing that lock
> > twice on every neigh create operation and I was trying hard
> > to avoid that overhead.
> 
> Actually, why don't we just move the expansion into the locked section?
> 
> Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>

Works for me, patch applied.

Thanks Herbert.