Re: [Xen-devel] [PATCH] introduce and used relaxed cpumask operations

[George Dunlap <george.dunlap@xxxxxxxxxxxxx>]

On 01/21/2015 03:06 PM, Jan Beulich wrote:
>>>> On 21.01.15 at 15:42, <george.dunlap@xxxxxxxxxxxxx> wrote:
>> On 01/21/2015 02:35 PM, Jan Beulich wrote:
>>>>>> On 21.01.15 at 15:28, <george.dunlap@xxxxxxxxxxxxx> wrote:
>>>> On 01/19/2015 03:58 PM, Jan Beulich wrote:
>>>>> @@ -780,10 +780,7 @@ rt_schedule(const struct scheduler *ops,
>>>>>      }
>>>>>      else
>>>>>      {
>>>>> -        cpumask_t cur_cpu;
>>>>> -        cpumask_clear(&cur_cpu);
>>>>> -        cpumask_set_cpu(cpu, &cur_cpu);
>>>>> -        snext = __runq_pick(ops, &cur_cpu);
>>>>> +        snext = __runq_pick(ops, cpumask_of(cpu));
>>>>>          if ( snext == NULL )
>>>>>              snext = rt_vcpu(idle_vcpu[cpu]);
>>>>>  
>>>>
>>>> This bit really needs explicit mention in the changelog.
>>>
>>> Already done in response to Andrew's similar request.
>>
>> Ah, sorry -- I saw that but for some reason thought he was talking about
>> a different hunk.
> 
> It was indeed, be the wording I added
> 
> Note that this
> - adds a volatile qualifier to cpumask_test_and_{clear,set}_cpu()
>   (should have been there from the beginning, like is the case for
>   cpumask_{clear,set}_cpu())
> - replaces several cpumask_clear()+cpumask_set_cpu(, n) pairs by the
>   simpler cpumask_copy(, cpumask_of(n)) (or just cpumask_of(n) if we
>   can do without copying)
> 
> isn't really specific to where these changes get done (as it's a
> common pattern).

Gotcha, thanks.

 -George

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