sched: let arch_update_cpu_topology indicate if topology changed

Change arch_update_cpu_topology so it returns 1 if the cpu topology changed
and 0 if it didn't change. This will be useful for the next patch which adds
a call to this function in partition_sched_domains.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 7 insertions, 1 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index ef212da928e8..fcfbbd9dbd60 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -7675,8 +7675,14 @@ static struct sched_domain_attr *dattr_cur;
  */
 static cpumask_t fallback_doms;
 
-void __attribute__((weak)) arch_update_cpu_topology(void)
+/*
+ * arch_update_cpu_topology lets virtualized architectures update the
+ * cpu core maps. It is supposed to return 1 if the topology changed
+ * or 0 if it stayed the same.
+ */
+int __attribute__((weak)) arch_update_cpu_topology(void)
 {
+        return 0;
 }
 
 /*