Re: Vnode API change: add global vnode cache

["J. Hannken-Illjes" <hannken%eis.cs.tu-bs.de@localhost>]

On 28 Apr 2014, at 13:24, Ilia Zykov <netbsd%izyk.ru@localhost> wrote:

> Sorry to disturb you.
> 
> But I have small comment about subject.
> I think it is unnecessary overload involve mount point in lookup for global 
> cache.
> You save few bytes for hashhead for every mount point, but loose effectively 
> lookup.
> Every lookup has one more compare for mp, and your hashtable will be more 
> bigger.
> In any case have hashhead and hashlock for every mount point is more flexible 
> way, IMHO.
> "struct mount" is a good place for this.

First, one of the goals here is to have one table for all vnodes.

Second, regarding space this even gets smaller.  A hash table allocates
next_power_of_two(desiredvnodes) list heads so every hash table accounts
for ~1.5 pointers per vnode.

--
J. Hannken-Illjes - hannken%eis.cs.tu-bs.de@localhost - TU Braunschweig 
(Germany)