[ECOS] Re: Problems with ppp and Windows

[Kelvin Lawson <klawson@ad-holdings.co.uk>]

Hi Øyvind,

> Ah! progress!

Excellent!

> - eCos could be a bit more friendly with the developer when running out of memory. Perhaps
> there are suitable facilities for detecting these situations. 
> In addition to the suggestions you made, perhaps it would be a good idea to add a fn that
> is invoked by the memory allocator when running out of memory? By default this could be
> an empty fn(handy breakpoint site), and the application could override it with something
> else(e.g. reset the board, invoke debugger, etc.).

Yes, sounds fine. In my case I'd be happy with just a debug message or 
assert in cyg_net_malloc() when not enough memory is available. I would 
think this should be a build option, rather than a default operation.

I think the proper place to add some debug notification is at the usage 
points of network mallocs. In the case of PPP, after the MALLOC() 
failed, it ought to have done something about it or printed some debug, 
rather than just carrying on broken.

> - reduce memory requirements for PPP and freebsd networking stack. 

For PPP there are a bunch of configuration options that aren't covered 
by the cyg_ppp_options_t structure. I've added a few options here to 
handle authorisation for dialin connections. Similarly you could extend 
it to disable things like VJ compression to reduce the memory requirements.

> - It is a bit hard to *know* how much memory is required. It would be nice to have a simple
> way of figuring this out at compile time.

Difficult to gauge in advance I would think. Perhaps someone could 
comment on where the default calculation comes from 
(256*1024)+(MAXSOCKETS*1024) ? On my system this was enough for one 
Ethernet device and plenty of connections. But it wasn't enough when 
adding PPP to the mix (unless I disabled eth0).

Cheers,
Kelvin.


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