svn commit: r192604 - in user/kmacy/releng_7_2_fcs/sys: dev/hwpmc sys

[John Baldwin]

On Friday 22 May 2009 5:45:43 pm Kip Macy wrote:
> Author: kmacy
> Date: Fri May 22 21:45:43 2009
> New Revision: 192604
> URL: http://svn.freebsd.org/changeset/base/192604
> 
> Log:
>   - remove pmc_kthread_mtx
>   - replace sleep/wakeup on kthread with a condvar

If you do not sleep on the kthread/kproc when waiting for a kthread to 
exit, then you open up a race window.  Usually this matters more for
any kthreads that live in a module since the race allows the module to
be unmapped before the thread is finished executing code from the module
resulting in a fatal page fault in the kernel.

-- 
John Baldwin