[En-Nut-Discussion] Killing Processes and malloc

[Moritz Struebe]

Ole Reinhardt schrieb:
> Hi,
>
>   
>> To solve this I was thinking of adding a allocated mem list for each 
>> process. This does bring a bit of overhead but I think is't a worth that 
>> price. The root of the list would be in NUTTHREADINFO. If a process gets 
>> kill you just have to work along this list and free the mem. On an atmel 
>> this will cost you 2 Bytes per process 2,5 Bytes per alloc. (I'd align 
>> the blocks to a word and then use 16bit pointers.) (BTW: It should be 
>> "long word" in heap.c:183)
>>     
>
> For me this sounds quite interesting. Especialy I'm interested in the
> way you start other applications at runtime. How do you solve the
> linking problem? Are thos "processes" always complete instances of a
> NutOS runtime?
>
>   
Basically I'm going the LegOS way. After compiling the kernel I create a 
linkerscript. When compiling an application I use that linkerscript. 
Therefore all the symbols which are in the kernel get resolved nicely 
and the library functions don't get included.
Then I "just" have to transmit the whole thing to the node and start it. 
(It's a little more complicated because you have to choose the right 
linkerscipt and also need some meta information as well as Flash 
allocalisation and you must not use the data-section, but that's the 
basic idea.) This part is already working. Therefore I'm now trying to 
get rid of all the pitfalls on the way.
APPLICATION("Thread2", 192, arg)
{
    /*
     * Endless loop in high priority thread.
     */
    NutThreadSetPriority(16);
    for (;;) {
        putchar('U');
        NutSleep(125);
    }
}
Ends up as 56 bytes. Including quite a bit of headerinformation.

>> Of course I'd implement this with ifdefs. Is there any interest in 
>> adding this to the trunk. Or has anyone got a better idea?
>>     
>
> Yes I think this could be quite interesting!
>   
Ok. I also already implemented realloc, because IMO this is a very handy 
function. But it all needs some more testing. I'll keep you tuned. :-)

Cheers
Morty


> Cheers,
>
> Ole
>
>