- Optimize wakeup() and its friends; if a thread waken up is being

  swapped in, we do not have to ask for the scheduler thread to do
  that.

- Assert that a process is not swapped out in runq functions and
  swapout().

- Introduce thread_safetoswapout() for readability.

- In swapout_procs(), perform a test that may block (check of a
  thread working on its vm map) first.  This lets us call swapout()
  with the sched_lock held, providing a better atomicity.

1 files changed, 4 insertions, 2 deletions

diff --git a/sys/kern/kern_condvar.c b/sys/kern/kern_condvar.c
index 822a4c9..55fba60 100644
--- a/sys/kern/kern_condvar.c
+++ b/sys/kern/kern_condvar.c
@@ -534,8 +534,10 @@ cv_wakeup(struct cv *cvp)
 			maybe_resched(td);
 		} else {
 			td->td_state = TDS_SWAPPED;
-			td->td_proc->p_sflag |= PS_SWAPINREQ;
-			wakeup(&proc0); /* XXXKSE */
+			if ((td->td_proc->p_sflag & PS_SWAPPINGIN) == 0) {
+				td->td_proc->p_sflag |= PS_SWAPINREQ;
+				wakeup(&proc0);
+			}
 		}
 		/* END INLINE EXPANSION */
 	}