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| author | Jeremy Fitzhardinge <jeremy@xensource.com> | 2007-10-16 20:51:30 +0200 |
|---|---|---|
| committer | Jeremy Fitzhardinge <jeremy@goop.org> | 2007-10-16 20:51:30 +0200 |
| commit | f0d733942750c1ee6358c3a4a1a5d7ba73b7122f (patch) | |
| tree | 32d0802b60078b6a2f43ce19d9019033ada6485d /arch/x86/xen/smp.c | |
| parent | Clean up duplicate includes in arch/i386/xen/ (diff) | |
| download | linux-f0d733942750c1ee6358c3a4a1a5d7ba73b7122f.tar.xz linux-f0d733942750c1ee6358c3a4a1a5d7ba73b7122f.zip | |
xen: yield to IPI target if necessary
When sending a call-function IPI to a vcpu, yield if the vcpu isn't
running.
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Diffstat (limited to 'arch/x86/xen/smp.c')
| -rw-r--r-- | arch/x86/xen/smp.c | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c index 557b8e24706a..865953e6f341 100644 --- a/arch/x86/xen/smp.c +++ b/arch/x86/xen/smp.c @@ -360,7 +360,8 @@ 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); @@ -389,9 +390,14 @@ 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 || |