Subject: Re: ifnet specific data
To: None <>
From: YAMAMOTO Takashi <>
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...