On Wed, Aug 09, 2006 at 07:18:35PM -0700, Bill Huey wrote:
> On Thu, Aug 10, 2006 at 12:05:57AM +0200, Esben Nielsen wrote:
> > I had a long discussion with Paul McKenney about this. I opposed the patch 
> > from a latency point of view: Suddenly a high-priority RT task could be 
> > made into releasing a task_struct. It would be better for latencies to 
> > defer it to a low priority task.
> > 
> > The conclusion we ended up with was that it is not a job for the RCU 
> > system, but it ought to be deferred to some other low priority task to 
> > free the task_struct.
> 
> I agree. It's just hack to get it not to crash at this time. It really
> should be done in another facility or utilizing another threading context.

Esben and company,

This is the second round of getting rid of the locking problems with free_task()

This extends the mmdrop logic with desched_thread() to also handle free_task()
requests as well. I believe this address your concerns and I'm open to review
of this patch.

Patch included:

bill