[Devel] Re: [PATCH v3 2/2] decrement static keys on real destroy time

[Tejun Heo]

Hello,

On Thu, Apr 26, 2012 at 3:17 PM, Glauber Costa <glommer at parallels.com> wrote:
>
>> No, what I mean is that why can't you do about the same mutexed
>> activated inside static_key API function instead of requiring every
>> user to worry about the function returning asynchronously.
>> ie. synchronize inside static_key API instead of in the callers.
>>
>
> Like this?

Yeah, something like that.  If keeping the inc operation a single
atomic op is important for performance or whatever reasons, you can
play some trick with large negative bias value while activation is
going on and use atomic_add_return() to determine both whether it's
the first incrementer and someone else is in the process of
activating.

Thanks.

-- 
tejun