Re: [Xen-devel] [PATCH v3 3/3] VT-d PI: restrict the vcpu number on a given pcpu

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 23.06.17 at 10:33, <chao.gao@xxxxxxxxx> wrote:
> On Fri, Jun 23, 2017 at 01:58:52AM -0600, Jan Beulich wrote:
>>>>> On 23.06.17 at 06:22, <chao.gao@xxxxxxxxx> wrote:
>>> On Fri, Jun 16, 2017 at 09:09:13AM -0600, Jan Beulich wrote:
>>>>>>> On 24.05.17 at 08:56, <chao.gao@xxxxxxxxx> wrote:
>>>>> +    {
>>>>> +        pi_cpu = cpumask_cycle(pi_cpu, &cpu_online_map);
>>>>
>>>>With this, how could the CPU be offline by the time you make it
>>>>back to the check above.
>>> 
>>> Thanks to point it out. It would incur a bug.
>>
>>I don't understand what you're trying to tell me here.
> 
> I agree with you that we might use an offline CPU's structure.
> and I treat it as a bug.

Ah, but I didn't say so. Instead I questioned how you would see
the pCPU going offline between the code above and the use of
pi_cpu further down. Most or all of what you say later in your
reply seems inapplicable because of this apparent
misunderstanding, so I'm not going to further comment on that.

Jan


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