Re: [PATCH 05/11 V5] workqueue: Add @bind arguement back withoutchange any thing

From: Tejun Heo
Date: Thu Sep 06 2012 - 12:51:43 EST


Hello, Lai.

On Thu, Sep 06, 2012 at 09:04:06AM +0800, Lai Jiangshan wrote:
> > This doesn't change anything. You're just moving the test to the
> > caller with comments there explaining how it won't change even if
> > gcwq->lock is released. It seems more confusing to me. The flag is
> > still protected by manager_mutex. How is this an improvement?
> >
>
> Some other bit of gcwq->flags is accessed(modified) without manager_mutex.
> making gcwq->flags be accessed only form gcwq->lock C.S. will help the reviewer.
>
> I don't like adding special things/code when not-absolutely-required.

I really fail to see this. The flag has to stay stable while
manage_mutex is held no matter where you test it. It doesn't make any
it any more readable whether you test it inside gcwq->lock with the
comment saying "this won't change while manager_mutex is held" or just
test it while manager_mutex is held. It is a synchronization oddity
no matter what and as long as it's well documented, I don't really see
the point in the change.

Thanks.

--
tejun
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