Re: [PATCH 4/7 V6] workqueue: fix idle worker depletion

[Lai Jiangshan]

On Sun, Sep 9, 2012 at 2:11 AM, Tejun Heo <tj@xxxxxxxxxx> wrote:
> On Sun, Sep 09, 2012 at 02:07:50AM +0800, Lai Jiangshan wrote:
>> when we release gcwq->lock and then grab it, we leave a hole that things
>> can be changed.
>>
>> I don't want to open a hole. if the hole has bug we have to fix it.
>> if the hole has no bug, we have to add lot of comments to explain it.
>>
>> When I write this reply. I am thinking: is the hole  has bug if
>> I release gcwq->lock here? result: no. But I don't want to add all things
>> what I have thought as comments to explain there is no bug even when we
>> open a hole. don't leave reviewers too much burden.
>
> We're already releasing gcwq->lock in maybe_create_worker().  That's
> the reason why @ret is set to true.  In addition, we already released
> the lock to grab manager_mutex.  So, you're not adding any burden.
> Please reuse the busy rebinding mechanism.
>

in 3.6 busy_worker_rebind() handle WORKER_REBIND bit,
not WORKER_UNBOUND bit.

busy_worker_rebind() takes struct work_struct *work argument, we have to
add new patch to add a helper and restruct it at first.

worker_maybe_bind_and_lock() 's mean is very clear here. busy_worker_rebind()
seems for busy workers, manager is not busy workers.

>
> --
> tejun
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