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>

diff --git a/arch/s390/kernel/topology.c b/arch/s390/kernel/topology.c
index a947899dcba1d55f56f8e00af05ab738293df6a3..bf96f1b5c6ec20b2539c8c2a1cf4ce46ee1e54ec 100644 (file)
--- a/arch/s390/kernel/topology.c
+++ b/arch/s390/kernel/topology.c
@@ -212,7 +212,7 @@ static void update_cpu_core_map(void)
                cpu_core_map[cpu] = cpu_coregroup_map(cpu);
 }
 
-void arch_update_cpu_topology(void)
+int arch_update_cpu_topology(void)
 {
        struct tl_info *info = tl_info;
        struct sys_device *sysdev;
@@ -221,7 +221,7 @@ void arch_update_cpu_topology(void)
        if (!machine_has_topology) {
                update_cpu_core_map();
                topology_update_polarization_simple();
-               return;
+               return 0;
        }
        stsi(info, 15, 1, 2);
        tl_to_cores(info);
@@ -230,6 +230,7 @@ void arch_update_cpu_topology(void)
                sysdev = get_cpu_sysdev(cpu);
                kobject_uevent(&sysdev->kobj, KOBJ_CHANGE);
        }
+       return 1;
 }
 
 static void topology_work_fn(struct work_struct *work)

diff --git a/include/linux/topology.h b/include/linux/topology.h
index 117f1b7405cfc92ff1c342d2d92a9f35c2e9cbb5..0c5b5ac36d8edc06bb6eb68975f8223e50631c05 100644 (file)
--- a/include/linux/topology.h
+++ b/include/linux/topology.h
@@ -49,7 +49,7 @@
        for_each_online_node(node)                      \
                if (nr_cpus_node(node))
 
-void arch_update_cpu_topology(void);
+int arch_update_cpu_topology(void);
 
 /* Conform to ACPI 2.0 SLIT distance definitions */
 #define LOCAL_DISTANCE         10

diff --git a/kernel/sched.c b/kernel/sched.c
index ef212da928e8953eb262880daf32800647789367..fcfbbd9dbd6083f677facab260c2395dfe46485f 100644 (file)
--- 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;
 }
 
 /*