Re: [PATCH 7/9] PM: Add suspend blocking work.

[Arve Hjønnevåg]

2010/4/23 Arve Hjønnevåg <arve@xxxxxxxxxxx>:
> On Fri, Apr 23, 2010 at 5:20 AM, Oleg Nesterov <oleg@xxxxxxxxxx> wrote:
>> On 04/23, Tejun Heo wrote:
>>>
>>> On 04/23/2010 03:08 AM, Arve Hjønnevåg wrote:
>>> > Allow work to be queued that will block suspend while it is pending
>>> > or executing. To get the same functionality in the calling code often
>>> > requires a separate suspend_blocker for pending and executing work, or
>>> > additional state and locking.
>>>
>>> Hmm... I think this can be implemented as pure wrapper around
>>> workqueue instead of injecting a flag and code into workqueue core.
>>> Adding @fn field to suspend_blocking_work struct and using a custom
>>> work function to call it and then invoke suspend_unblock() should be
>>> enough, right?  Oh, dedicated queue functions will be needed too.  I
>>> don't think it's wise to meddle with workqueue core code for this.
>>
>> Completely agreed. The patch adds very "strange" hacks into workqueue
>> code to solve the very specific problems.
>>
>
> I want the suspend blocker active when the work is pending or running.
> I did not see a way to do this on top of the workqueue api without
> adding additional locking.
>

I can remove the WORK_STRUCT_SUSPEND_BLOCKING flag and instead add an
argument to __queue_work and __cancel_work_timer (or use separate
copies) if you think that would be better. It would avoid increasing
the alignment requirement of cpu_workqueue_struct, but it will
probably add more code than the current patch.

-- 
Arve Hjønnevåg
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