Merge branch 'xen-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen

* 'xen-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen:
  xfs: eagerly remove vmap mappings to avoid upsetting Xen
  xen: add some debug output for failed multicalls
  xen: fix incorrect vcpu_register_vcpu_info hypercall argument
  xen: ask the hypervisor how much space it needs reserved
  xen: lock pte pages while pinning/unpinning
  xen: deal with stale cr3 values when unpinning pagetables
  xen: add batch completion callbacks
  xen: yield to IPI target if necessary
  Clean up duplicate includes in arch/i386/xen/
  remove dead code in pgtable_cache_init
  paravirt: clean up lazy mode handling
  paravirt: refactor struct paravirt_ops into smaller pv_*_ops

1 files changed, 10 insertions, 4 deletions

diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index 4fa33c27ccb6..d53bf9d8a72d 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -370,7 +370,8 @@ int xen_smp_call_function_mask(cpumask_t mask, void (*func)(void *),
                                void *info, int wait)
 {
         struct call_data_struct data;
-        int cpus;
+        int cpus, cpu;
+        bool yield;
 
         /* Holding any lock stops cpus from going down. */
         spin_lock(&call_lock);
@@ -399,9 +400,14 @@ int xen_smp_call_function_mask(cpumask_t mask, void (*func)(void *),
         /* Send a message to other CPUs and wait for them to respond */
         xen_send_IPI_mask(mask, XEN_CALL_FUNCTION_VECTOR);
 
-        /* Make sure other vcpus get a chance to run.
-           XXX too severe?  Maybe we should check the other CPU's states? */
-        HYPERVISOR_sched_op(SCHEDOP_yield, 0);
+        /* Make sure other vcpus get a chance to run if they need to. */
+        yield = false;
+        for_each_cpu_mask(cpu, mask)
+                if (xen_vcpu_stolen(cpu))
+                        yield = true;
+
+        if (yield)
+                HYPERVISOR_sched_op(SCHEDOP_yield, 0);
 
         /* Wait for response */
         while (atomic_read(&data.started) != cpus ||