Re: [Xen-devel] [PATCH v2 5/6] virt, sched: add cpu pinning to smp_call_sync_on_phys_cpu()
From: Juergen Gross
Date: Mon Mar 21 2016 - 10:21:21 EST
On 21/03/16 14:42, Jan Beulich wrote:
>>>> On 21.03.16 at 13:24, <JGross@xxxxxxxx> wrote:
>> @@ -758,9 +759,14 @@ struct smp_sync_call_struct {
>> static void smp_call_sync_callback(struct work_struct *work)
>> {
>> struct smp_sync_call_struct *sscs;
>> + unsigned int cpu = smp_processor_id();
>
> So this obtains the vCPU number, yet ...
>
>> sscs = container_of(work, struct smp_sync_call_struct, work);
>> + preempt_disable();
>> + hypervisor_pin_vcpu(cpu);
>
> ... here you're supposed to pass a pCPU number.
>
> Also don't you need to call smp_processor_id() after preempt_disable()?
No, I'm running on the workqueue bound to the specific (v)cpu and I'm
expecting this vcpu to be pinned to the same numbered pcpu.
preempt_disable() is just called to avoid scheduling of another thread
while the override pinning is active.
Juergen