On 04/17/2014 03:51 AM, Tejun Heo wrote:
> Hello,
>
> On Tue, Mar 25, 2014 at 05:56:04PM +0800, Lai Jiangshan wrote:
>> freezing is nothing related to pools, but POOL_FREEZING adds a connection,
>> and causes freeze_workqueues_begin() and thaw_workqueues() complicated.
>>
>> Since freezing is workqueue instance attribute, so we introduce __WQ_FREEZING
>> to wq->flags instead and remove POOL_FREEZING.
>>
>> we set __WQ_FREEZING only when freezable(to simplify
>> pwq_adjust_max_active()),
>> make freeze_workqueues_begin() and thaw_workqueues() fast skip non-freezable
>> wq.
>
> Please wrap the description to 80 columns.
>
>> @@ -3730,18 +3726,13 @@ static void pwq_unbound_release_workfn(struct
>> work_struct *work)
>> static void pwq_adjust_max_active(struct pool_workqueue *pwq)
>> {
>> struct workqueue_struct *wq = pwq->wq;
>> - bool freezable = wq->flags & WQ_FREEZABLE;
>>
>> - /* for @wq->saved_max_active */
>> + /* for @wq->saved_max_active and @wq->flags */
>> lockdep_assert_held(&wq->mutex);
>>
>> - /* fast exit for non-freezable wqs */
>> - if (!freezable && pwq->max_active == wq->saved_max_active)
>> - return;
>> -
>
> Why are we removing the above? Can't we still test __WQ_FREEZING as
> we're holding wq->mutex? I don't really mind removing the
> optimization but the patch description at least has to explain what's
> going on.
This part was in other old patch: https://lkml.org/lkml/2013/4/3/756
I admit the changelogs(old patch&this) are bad.
But I still consider it would be better if we split it to two patches:
(https://lkml.org/lkml/2013/4/3/748 & https://lkml.org/lkml/2013/4/3/756)
There are different aims in the patches.
Any thinks? And sorry for I didn't keep to push the patches at that time.
Thanks
Lai
>
> ...
>> list_for_each_entry(wq, &workqueues, list) {
>> + if (!(wq->flags & WQ_FREEZABLE))
>> + continue;
>
> Ah, okay, you're not calling the function at all if WQ_FREEZABLE is
> not set. I couldn't really understand what you were trying to say in
> the patch description. Can you please try to refine the description
> more? It's better to be verbose and clear than short and difficult to
> understand.
>
> Thanks.
>
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