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From: wbrown@beva.bev.lbl.gov (Bill Brown)
Newsgroups: comp.realtime
Subject: Re: vxWorks memory partitions
Keywords: free forget debug_cycle
Message-ID: <2603@helios.ee.lbl.gov>
Date: 11 May 89 14:15:48 GMT
References: <3213@ncar.ucar.edu>
Sender: usenet@helios.ee.lbl.gov
Reply-To: wlbrown@lbl.gov (Bill Brown)
Organization: Lawrence Berkeley Laboratory, Berkeley
Lines: 56

In article <3213@ncar.ucar.edu> cmiller@hao.ucar.edu (Charlie Miller) writes:
>
>The apparent problem: In the debug cycle of modify, load, try, modify, reload,
>vxWorks eventually uses up all available memory by not deallocating partitions
>allocated to each program loaded even though the new program has the same
>name.  It just allocates new partitions until no more are available then
>refuses to allow loads.  The only way I have found to get around this is
>to manually do free(program_name) from the shell or to reset. There must be
>a way to automate this process.
>
>Any suggestions??
>
>Also, I would like to hear from other vxWorks users out there.  What are
>your applications, etc.
>
>Charlie Miller
>cmiller@hao.ucar.edu


An interesting idea, this.  I've wanted to do something like this (similar
to the 'forget' word in FORTH) but never thought of trying 'free'.

I usually have more than one file that needs to be loaded and I use a
script like this:
	ld <framis_1.o
	ld <framis_2.o
	ld <doohickey.o
    which resides in a file called "ld_this_stuff"

After doing ->cd "host:~me/vxworks/current_dir" in invoke the script by
	<ld_this_stuff
    
Now it seems that if having another script called 'forget' (oops - FORTH again)
with a call to 'free' for each function ought to do it.  It gets invoked
before the first "ld" call in the load script.

A more elegant way of doing this would be to write a "forget" function
that gets loaded before the first "real" function.  When invoked, it would
use the symbol table to "free" the memory occupied by every function
loaded after itself and then perhaps it deletes itself.  (I'm fairly sure
that stuff gets put in the symbol table in the order it is loaded.)

It would be nice if something like this was included in the kernel prom.

Hmmmm - It shouldn't be too hard to write such a beast, but I don't have the
time right now to do it (right, Steve???).  If anybody does it I hope they
will share it.

							-bill
							WLBrown@lbl.gov
							(415)486-6411


Disclaimer:  These opinions are my own and have nothing to do with the
    official policy or management of L.B.L, who probably couldn't care 
    less about employees who play with trains.