[PATCH] sched: add debugging

These conditions should now be impossible, and we need to fix them if they
happen.

Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 4 insertions, 10 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index 41e69b5ee652..8b035a8b3c30 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -1942,15 +1942,7 @@ static int load_balance(int this_cpu, runqueue_t *this_rq,
                 goto out_balanced;
         }
 
-        /*
-         * This should be "impossible", but since load
-         * balancing is inherently racy and statistical,
-         * it could happen in theory.
-         */
-        if (unlikely(busiest == this_rq)) {
-                WARN_ON(1);
-                goto out_balanced;
-        }
+        BUG_ON(busiest == this_rq);
 
         schedstat_add(sd, lb_imbalance[idle], imbalance);
 
@@ -2052,11 +2044,13 @@ static int load_balance_newidle(int this_cpu, runqueue_t *this_rq,
         }
 
         busiest = find_busiest_queue(group);
-        if (!busiest || busiest == this_rq) {
+        if (!busiest) {
                 schedstat_inc(sd, lb_nobusyq[NEWLY_IDLE]);
                 goto out_balanced;
         }
 
+        BUG_ON(busiest == this_rq);
+
         /* Attempt to move tasks */
         double_lock_balance(this_rq, busiest);