Re: Modules loading modules?

[Paul Goyette <paul%whooppee.com@localhost>]

On Tue, 3 Aug 2010, haad wrote:

> > Well, still no hurry, but it would be nice if some additional eyes were 
> > pointed this way.  I've got the recursive-module-load test case added
> > to the existing tests/modules/ stuff (and it works)!
> >
> > BTW, since this is changing the kernel ABI, I guess it will need a 
> > version bump.  Do we have any other bumps coming soon that we can 
> > "share"?
>
> I talked with Andrew today and he said that basicaly we can use
> mutex_owned for this particular case. That should make your code much
> simpler :) sorry for any additional work :)

Well, we've come full circle!  :)

It seems to me that, even if it is "OK to use mutex_owned() for this 
particular case", perhaps we should not.  Most everyone seemed to agree 
that your condvar solution was "technically correct", and if we did use 
the mutex_owned() solution it would only serve as a temptation for 
someone else in the future!

We now have two solutions, both of which actually work (tested on my 
home machine).  One solution (mutex_owned) might be slightly simpler and 
slightly more efficient than the other (condvar), but this section of 
code is certainly not performance-critical.  Therefore, is there any 
reason for preferring the mutex_owned solution?

I'm happy to go either way based on concensus here, but I'm leaning 
towards the condvar solution.  It doesn't require any "exemptions" or 
long explanations of why it is "OK to use mutex_owned" in ways that 
would appear to violate our own documentation.  And it also addresses 
eeh's (and mrg's) concerns of keeping the lock across potentially 
long-duration  operations.


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