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

[linux-2.6.git] / arch / x86 / xen / smp.c

diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index 4fa33c27ccb6d4d4e6a7619f7bd8c46c25f36a2c..d53bf9d8a72d083ed0274860c042be3ec6ff3c2e 100644 (file)
--- 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 ||