VFS: C99 sparse format for struct vfsops

[John Baldwin]

On 02-Jun-2003 Paul Richards wrote:
> On Mon, 2003-06-02 at 21:04, Paul Richards wrote:
> 
>> 
>> The tradeoff with using an index into an array is that there'd be a
>> heavy penalty for growing the array if an extra method didn't fit, but
>> that would be exceptionally rare and with our present usage we'd never
>> have that happen.
> 
> I'm not sure this is actually a problem after all since the Interface
> doesn't change and therefore we know a-priori how many methods there can
> be so we can pre-allocate an array. I wonder why Doug didn't do this,
> perhaps he thought that there'd be very large interfaces and 255 was a
> reasonable compromise for a cache. However, in practice we'd save a lot
> of space per kobj by preallocating the actual number of entries we
> needed for the Interface instead and then we could do away with the _ce
> problem. This would actually speed up the dispatch a lot too since we
> wouldn't have to traverse a list looking for a matching method entry and
> could call the function directly from the method table.
> 
> Doug, am I missing something?

Well, it's dfr@ rather than doug@ :)  (dfr@ cc'd)

-- 

John Baldwin <jhb at FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve!"  -  http://www.FreeBSD.org/