Re: [PATCH 3/3 V8] workqueue: Allow modifying low level unbound workqueue cpumask

[Lai Jiangshan <laijs@cn.fujitsu.com>]

On 04/28/2015 09:44 AM, Lai Jiangshan wrote:

>>>  
>>> +	/* save the user configured attrs */
>>> +	cpumask_and(new_attrs->cpumask, attrs->cpumask, cpu_possible_mask);
>>
>> Wouldn't this make a lot more sense above when copying @attrs into
>> @new_attrs?  The comment there even says "make a copy of @attrs and
>> sanitize it".  Copy to @new_attrs, mask with wq_unbound_cpumask and
>> fall back to wq_unbound_cpumask if empty.


We need to save the user original configured attrs.
When any time wq_unbound_cpumask is changed, we should use
the user original configured attrs (cpumask) to re-calculate
the pwqs and avoid losing any information.

> 
> It should be:
> 
> +	copy_workqueue_attrs(new_attrs, attrs);
> +	cpumask_and(new_attrs->cpumask, new_attrs->cpumask, cpu_possible_mask);
>