- Re-implement lock profiling in such a way that it no longer breaks

   the ABI when enabled.  There is no longer an embedded lock_profile_object
   in each lock.  Instead a list of lock_profile_objects is kept per-thread
   for each lock it may own.  The cnt_hold statistic is now always 0 to
   facilitate this.
 - Support shared locking by tracking individual lock instances and
   statistics in the per-thread per-instance lock_profile_object.
 - Make the lock profiling hash table a per-cpu singly linked list with a
   per-cpu static lock_prof allocator.  This removes the need for an array
   of spinlocks and reduces cache contention between cores.
 - Use a seperate hash for spinlocks and other locks so that only a
   critical_enter() is required and not a spinlock_enter() to modify the
   per-cpu tables.
 - Count time spent spinning in the lock statistics.
 - Remove the LOCK_PROFILE_SHARED option as it is always supported now.
 - Specifically drop and release the scheduler locks in both schedulers
   since we track owners now.

In collaboration with:	Kip Macy
Sponsored by:	Nokia

1 files changed, 2 insertions, 0 deletions

diff --git a/sys/kern/kern_thread.c b/sys/kern/kern_thread.c
index e176b87..93ff5a7 100644
--- a/sys/kern/kern_thread.c
+++ b/sys/kern/kern_thread.c
@@ -555,6 +555,8 @@ thread_link(struct thread *td, struct proc *p)
 	td->td_flags    = TDF_INMEM;
 
 	LIST_INIT(&td->td_contested);
+	LIST_INIT(&td->td_lprof[0]);
+	LIST_INIT(&td->td_lprof[1]);
 	sigqueue_init(&td->td_sigqueue, p);
 	callout_init(&td->td_slpcallout, CALLOUT_MPSAFE);
 	TAILQ_INSERT_HEAD(&p->p_threads, td, td_plist);