Re: Proposal: B_ARRIER (addresses wapbl performance?)

[Jason Thorpe <thorpej%shagadelic.org@localhost>]

On Dec 9, 2008, at 3:27 PM, Manuel Bouyer wrote:

> Because the ordering constraint bewteen journal and other writes are
> both way, the way I understand it: some "other writes" have to happen
> before some journal writes, and some "other writes" have to happen
> after some journal writes.  I guess this doens't leave much writes  
> with
> no ordered contraints.

Journal writes really only need to be constrained with respect to the  
metadata they're journaling, and themselves (i.e. entry hits oxide  
before the header update that makes it valid does).  Doesn't matter  
for data writes (assuming you're not journaling data, which we don't).

> --
> Manuel Bouyer <bouyer%antioche.eu.org@localhost>
>     NetBSD: 26 ans d'experience feront toujours la difference
> --

-- thorpej