Re: [PATCH] io_uring: consider cgroup setting when binding sqpoll cpu

[Hao Xu <haoxu@linux.alibaba.com>]

在 2021/8/17 上午12:58, Jens Axboe 写道:
> On 8/16/21 12:04 AM, Hao Xu wrote:
>> 在 2021/8/15 下午11:19, Jens Axboe 写道:
>>> On 8/15/21 9:10 AM, Hao Xu wrote:
>>>> Since sqthread is userspace like thread now, it should respect cgroup
>>>> setting, thus we should consider current allowed cpuset when doing
>>>> cpu binding for sqthread.
>>>
>>> This seems a bit convoluted for what it needs to do. Surely we can just
>>> test sqd->sq_cpu directly in the task_cs()?
>> I didn't know task_cs() before, it seems to be a static function, which
>> is called by cpuset_cpus_allowed(), and this one is exposed.
> 
> But it'd be a much saner to add a helper for this rather than add all
> of that boiler plate code to io_uring just to check for whether or not
> a CPU is set in a mask.
I looked into cpuset_cpus_allowed(), it seems the code logic
guarantee_online_cpus() is neccessary? It guarantees the cpumask
returned are all online cpus.


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