sched: Fix task_hot() test order

Make sure not to access sched_fair fields before verifying it is
indeed a sched_fair task.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
CC: stable@kernel.org
LKML-Reference: <20091216170517.577998058@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 3 insertions, 3 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index 9c30858b6463..1d8ca25dd6fb 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2046,6 +2046,9 @@ task_hot(struct task_struct *p, u64 now, struct sched_domain *sd)
 {
         s64 delta;
 
+        if (p->sched_class != &fair_sched_class)
+                return 0;
+
         /*
          * Buddy candidates are cache hot:
          */
@@ -2054,9 +2057,6 @@ task_hot(struct task_struct *p, u64 now, struct sched_domain *sd)
                          &p->se == cfs_rq_of(&p->se)->last))
                 return 1;
 
-        if (p->sched_class != &fair_sched_class)
-                return 0;
-
         if (sysctl_sched_migration_cost == -1)
                 return 1;
         if (sysctl_sched_migration_cost == 0)