yield() in kernel CAN'T yield control for MOD_LOAD thread

[John Baldwin]

On Wednesday 25 August 2004 03:06 am, yangshazhou at hotmail.com wrote:
> Hi all,
>     This problem delay me for quite a long time.
>     I've built two klds, I'd like to see the result one's running to the
> other's. In one kld's MOD_LOAD subroutine, I make a long 'for' loop, in
> which it DELAY(1000) and then call yield(curthread,NULL). When the module
> was loaded by kldload, the system failed to response until the loop quit.
> The loop seems like that:
>  for(i=0;i<8000;i++){
>     ......
>   DELAY(1000);
>   yield(curthread,NULL);
>  }
>
>     My system is 5.2.1-release. Thanks.

You could try having the first one wait on a condition variable that the 
second module's MOD_LOAD does a wakeup on.

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