---

yaml
---
r: 121346
b: refs/heads/master
c: 720f549
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 34f28ecd0f4bdc733c681294d02d9fab5880591b
+refs/heads/master: 720f54988e17b33f3f477010b3a68ee872d20d5a

trunk/kernel/sched.c

@@ -9275,24 +9275,50 @@ cpuacct_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
 	kfree(ca);
 }
 
+static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu)
+{
+	u64 *cpuusage = percpu_ptr(ca->cpuusage, cpu);
+	u64 data;
+
+#ifndef CONFIG_64BIT
+	/*
+	 * Take rq->lock to make 64-bit read safe on 32-bit platforms.
+	 */
+	spin_lock_irq(&cpu_rq(cpu)->lock);
+	data = *cpuusage;
+	spin_unlock_irq(&cpu_rq(cpu)->lock);
+#else
+	data = *cpuusage;
+#endif
+
+	return data;
+}
+
+static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu, u64 val)
+{
+	u64 *cpuusage = percpu_ptr(ca->cpuusage, cpu);
+
+#ifndef CONFIG_64BIT
+	/*
+	 * Take rq->lock to make 64-bit write safe on 32-bit platforms.
+	 */
+	spin_lock_irq(&cpu_rq(cpu)->lock);
+	*cpuusage = val;
+	spin_unlock_irq(&cpu_rq(cpu)->lock);
+#else
+	*cpuusage = val;
+#endif
+}
+
 /* return total cpu usage (in nanoseconds) of a group */
 static u64 cpuusage_read(struct cgroup *cgrp, struct cftype *cft)
 {
 	struct cpuacct *ca = cgroup_ca(cgrp);
 	u64 totalcpuusage = 0;
 	int i;
 
-	for_each_possible_cpu(i) {
-		u64 *cpuusage = percpu_ptr(ca->cpuusage, i);
-
-		/*
-		 * Take rq->lock to make 64-bit addition safe on 32-bit
-		 * platforms.
-		 */
-		spin_lock_irq(&cpu_rq(i)->lock);
-		totalcpuusage += *cpuusage;
-		spin_unlock_irq(&cpu_rq(i)->lock);
-	}
+	for_each_present_cpu(i)
+		totalcpuusage += cpuacct_cpuusage_read(ca, i);
 
 	return totalcpuusage;
 }
@@ -9309,13 +9335,9 @@ static int cpuusage_write(struct cgroup *cgrp, struct cftype *cftype,
 		goto out;
 	}
 
-	for_each_possible_cpu(i) {
-		u64 *cpuusage = percpu_ptr(ca->cpuusage, i);
+	for_each_present_cpu(i)
+		cpuacct_cpuusage_write(ca, i, 0);
 
-		spin_lock_irq(&cpu_rq(i)->lock);
-		*cpuusage = 0;
-		spin_unlock_irq(&cpu_rq(i)->lock);
-	}
 out:
 	return err;
 }