From 6db5580cde5ade33099498218e507f216824360b Mon Sep 17 00:00:00 2001
From: Heiko Carstens <heiko.carstens@de.ibm.com>
Date: Tue, 27 Dec 2011 11:27:16 +0100
Subject: [PATCH] --- yaml --- r: 280624 b: refs/heads/master c:
 d68bddb7329a4d47d950d6b0745a7e274d230ed4 h: refs/heads/master v: v3

---
 [refs]                                 |  2 +-
 trunk/arch/s390/include/asm/topology.h |  2 ++
 trunk/arch/s390/kernel/smp.c           |  2 ++
 trunk/arch/s390/kernel/topology.c      | 34 ++++++++++++++++++++------
 4 files changed, 31 insertions(+), 9 deletions(-)

diff --git a/[refs] b/[refs]
index aa842f9850e1..ee12e50f08a5 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: c5328901aa1db134325607d65527742d8be07f7d
+refs/heads/master: d68bddb7329a4d47d950d6b0745a7e274d230ed4
diff --git a/trunk/arch/s390/include/asm/topology.h b/trunk/arch/s390/include/asm/topology.h
index 7016dd7b6bc4..0837de80c351 100644
--- a/trunk/arch/s390/include/asm/topology.h
+++ b/trunk/arch/s390/include/asm/topology.h
@@ -35,11 +35,13 @@ int topology_cpu_init(struct cpu *);
 int topology_set_cpu_management(int fc);
 void topology_schedule_update(void);
 void store_topology(struct sysinfo_15_1_x *info);
+void topology_expect_change(void);
 
 #else /* CONFIG_SCHED_BOOK */
 
 static inline void topology_schedule_update(void) { }
 static inline int topology_cpu_init(struct cpu *cpu) { return 0; }
+static inline void topology_expect_change(void) { }
 
 #endif /* CONFIG_SCHED_BOOK */
 
diff --git a/trunk/arch/s390/kernel/smp.c b/trunk/arch/s390/kernel/smp.c
index 109e7422bb20..8aba77df68a9 100644
--- a/trunk/arch/s390/kernel/smp.c
+++ b/trunk/arch/s390/kernel/smp.c
@@ -867,6 +867,7 @@ static ssize_t cpu_configure_store(struct sys_device *dev,
 			if (!rc) {
 				smp_cpu_state[cpu] = CPU_STATE_STANDBY;
 				cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
+				topology_expect_change();
 			}
 		}
 		break;
@@ -876,6 +877,7 @@ static ssize_t cpu_configure_store(struct sys_device *dev,
 			if (!rc) {
 				smp_cpu_state[cpu] = CPU_STATE_CONFIGURED;
 				cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
+				topology_expect_change();
 			}
 		}
 		break;
diff --git a/trunk/arch/s390/kernel/topology.c b/trunk/arch/s390/kernel/topology.c
index 2abad3014928..e06fb852d386 100644
--- a/trunk/arch/s390/kernel/topology.c
+++ b/trunk/arch/s390/kernel/topology.c
@@ -31,7 +31,6 @@ struct mask_info {
 static int topology_enabled = 1;
 static void topology_work_fn(struct work_struct *work);
 static struct sysinfo_15_1_x *tl_info;
-static struct timer_list topology_timer;
 static void set_topology_timer(void);
 static DECLARE_WORK(topology_work, topology_work_fn);
 /* topology_lock protects the core linked list */
@@ -297,12 +296,30 @@ static void topology_timer_fn(unsigned long ignored)
 	set_topology_timer();
 }
 
+static struct timer_list topology_timer =
+	TIMER_DEFERRED_INITIALIZER(topology_timer_fn, 0, 0);
+
+static atomic_t topology_poll = ATOMIC_INIT(0);
+
 static void set_topology_timer(void)
 {
-	topology_timer.function = topology_timer_fn;
-	topology_timer.data = 0;
-	topology_timer.expires = jiffies + 60 * HZ;
-	add_timer(&topology_timer);
+	if (atomic_add_unless(&topology_poll, -1, 0))
+		mod_timer(&topology_timer, jiffies + HZ / 10);
+	else
+		mod_timer(&topology_timer, jiffies + HZ * 60);
+}
+
+void topology_expect_change(void)
+{
+	if (!MACHINE_HAS_TOPOLOGY)
+		return;
+	/* This is racy, but it doesn't matter since it is just a heuristic.
+	 * Worst case is that we poll in a higher frequency for a bit longer.
+	 */
+	if (atomic_read(&topology_poll) > 60)
+		return;
+	atomic_add(60, &topology_poll);
+	set_topology_timer();
 }
 
 static int __init early_parse_topology(char *p)
@@ -379,8 +396,10 @@ static ssize_t dispatching_store(struct sysdev_class *dev,
 	if (cpu_management == val)
 		goto out;
 	rc = topology_set_cpu_management(val);
-	if (!rc)
-		cpu_management = val;
+	if (rc)
+		goto out;
+	cpu_management = val;
+	topology_expect_change();
 out:
 	mutex_unlock(&smp_cpu_state_mutex);
 	put_online_cpus();
@@ -438,7 +457,6 @@ static int __init topology_init(void)
 		topology_update_polarization_simple();
 		goto out;
 	}
-	init_timer_deferrable(&topology_timer);
 	set_topology_timer();
 out:
 	update_cpu_core_map();