svn commit: r189787 - head/sys/kern

[Jeff Roberson]

Author: jeff
Date: Sat Mar 14 11:41:36 2009
New Revision: 189787
URL: http://svn.freebsd.org/changeset/base/189787

Log:
   - Fix an error that occurs when mp_ncpu is an odd number.  steal_thresh
     is calculated as 0 which causes errors elsewhere.
  
  Submitted by:	KOIE Hidetaka <koie at suri.co.jp>
  
   - When sched_affinity() is called with a thread that is not curthread we
     need to handle the ON_RUNQ() case by adding the thread to the correct
     run queue.
  
  Submitted by:	Justin Teller <justin.teller at gmail.com>
  
  MFC after:	1 Week

Modified:
  head/sys/kern/sched_ule.c

Modified: head/sys/kern/sched_ule.c
==============================================================================
--- head/sys/kern/sched_ule.c	Sat Mar 14 08:34:45 2009	(r189786)
+++ head/sys/kern/sched_ule.c	Sat Mar 14 11:41:36 2009	(r189787)
@@ -1337,11 +1337,11 @@ sched_initticks(void *dummy)
 	 */
 	balance_interval = realstathz;
 	/*
-	 * Set steal thresh to log2(mp_ncpu) but no greater than 4.  This
-	 * prevents excess thrashing on large machines and excess idle on
-	 * smaller machines.
+	 * Set steal thresh to roughly log2(mp_ncpu) but no greater than 4. 
+	 * This prevents excess thrashing on large machines and excess idle 
+	 * on smaller machines.
 	 */
-	steal_thresh = min(ffs(mp_ncpus) - 1, 3);
+	steal_thresh = min(fls(mp_ncpus) - 1, 3);
 	affinity = SCHED_AFFINITY_DEFAULT;
 #endif
 }
@@ -2417,6 +2417,11 @@ sched_affinity(struct thread *td)
 	ts = td->td_sched;
 	if (THREAD_CAN_SCHED(td, ts->ts_cpu))
 		return;
+	if (TD_ON_RUNQ(td)) {
+		sched_rem(td);
+		sched_add(td, SRQ_BORING);
+		return;
+	}
 	if (!TD_IS_RUNNING(td))
 		return;
 	td->td_flags |= TDF_NEEDRESCHED;