arla-related hangs/pauses

[Love]

Nickolai Zeldovich <kolya at MIT.EDU> writes:

> > How many fcache-nodes are you using ?

> fs getca says:
> 
>   Arla is using 65234 of the cache's available 307200 1K byte blocks
>   (and 15018 of the cache's available 20000 vnodes)
> 
> The fcache-used count always stays at 15000 or a little above, and
> always decays towards 15000:

Ah, that part of the problem, each time the cleaner want to gc a node its
sent down the kernel and the kernel does a linear search over the nodes to
find it. I have patches from currrent that changed the linked list to a
hash that gives you back part of the performance, I've to commit
them. There are other problems with current that we need to fix first.

The gc should really be done (at least parts of it) in kernel, and not in
arlad.

Love