diff --git a/xen/arch/x86/acpi/power.c b/xen/arch/x86/acpi/power.c
index e3d6eefe65..3ad7dfc9a3 100644
--- a/xen/arch/x86/acpi/power.c
+++ b/xen/arch/x86/acpi/power.c
@@ -306,7 +306,6 @@ static int enter_state(u32 state)
     cpufreq_add_cpu(0);
 
  enable_cpu:
-    rcu_barrier();
     mtrr_aps_sync_begin();
     enable_nonboot_cpus();
     mtrr_aps_sync_end();
diff --git a/xen/arch/x86/sysctl.c b/xen/arch/x86/sysctl.c
index a95923e591..b0cb1b57e7 100644
--- a/xen/arch/x86/sysctl.c
+++ b/xen/arch/x86/sysctl.c
@@ -84,12 +84,9 @@ long cpu_up_helper(void *data)
     unsigned int cpu = (unsigned long)data;
     int ret = cpu_up(cpu);
 
+    /* Have one more go on EBUSY. */
     if ( ret == -EBUSY )
-    {
-        /* On EBUSY, flush RCU work and have one more go. */
-        rcu_barrier();
         ret = cpu_up(cpu);
-    }
 
     if ( !ret && !opt_smt &&
          cpu_data[cpu].compute_unit_id == INVALID_CUID &&
@@ -109,12 +106,9 @@ long cpu_down_helper(void *data)
 {
     int cpu = (unsigned long)data;
     int ret = cpu_down(cpu);
+    /* Have one more go on EBUSY. */
     if ( ret == -EBUSY )
-    {
-        /* On EBUSY, flush RCU work and have one more go. */
-        rcu_barrier();
         ret = cpu_down(cpu);
-    }
     return ret;
 }
 
diff --git a/xen/common/cpu.c b/xen/common/cpu.c
index 31953f32e4..1f976db0a5 100644
--- a/xen/common/cpu.c
+++ b/xen/common/cpu.c
@@ -4,6 +4,7 @@
 #include <xen/init.h>
 #include <xen/sched.h>
 #include <xen/stop_machine.h>
+#include <xen/rcupdate.h>
 
 unsigned int __read_mostly nr_cpu_ids = NR_CPUS;
 #ifndef nr_cpumask_bits
@@ -53,6 +54,7 @@ void put_cpu_maps(void)
 
 void cpu_hotplug_begin(void)
 {
+    rcu_barrier();
     write_lock(&cpu_add_remove_lock);
 }