Subject: Re: ifnet specific data
To: None <wrstuden@netbsd.org>
From: YAMAMOTO Takashi <yamt@mwd.biglobe.ne.jp>
List: tech-net
Date: 09/19/2006 12:49:31
> On Tue, Sep 19, 2006 at 07:34:32AM +0900, YAMAMOTO Takashi wrote:
> > > Yes & no. What we could do is have the dictionary and have shadow
> > > variables. Change the dict, and the shadow variables change too. Think of
> > > these variables as caching the result of key lookups. While we can't look
> > > in the dictionary in interrupt context, if we do it right, we _can_ look
> > > at the shadow variables. Put another way, as long as we don't do it wrong,
> > > we can read the shadow variables.
> > >
> > > This does mean we need to know when the dictionary changes (as long as the
> > > driver gets called, not hard). Also, it means that the dictionary can't
> > > contain state that needs gathering at interrupt context. Though I doubt
> > > anyone would use a properties dictionary for that. :-)
> >
> > what's the point to have a dictionary at all in addition to the
> > "shadow variables"?
>
> I'm assuming that not everything in the dictionary needs a shadow
> variable. If that's wrong (i.e. everything needs a shadow variable),
> there's no point.
>
> I also expect that we will be adding more-general device driver uses for
> a dictionary. So we will have both "non-shadow-variable" uses for a dict,
> and we will need to figure out how to handle this eventually.
>
> Take care,
>
> Bill
can you explain why you think an item should be in both of
"shadow variables" and a dictionary?
i don't see any benefit to use proplib dictionary here...
YAMAMOTO Takashi