sched: reintroduce cache-hot affinity

reintroduce a simplified version of cache-hot/cold scheduling
affinity. This improves performance with certain SMP workloads,
such as sysbench.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index cea1fa3..a17b785 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -74,6 +74,8 @@
  */
 const_debug unsigned int sysctl_sched_wakeup_granularity = 10000000UL;
 
+const_debug unsigned int sysctl_sched_migration_cost = 500000UL;
+
 /**************************************************************
  * CFS operations on generic schedulable entities:
  */