Messages in this thread | | | From | Lai Jiangshan <> | Date | Thu, 28 May 2020 16:35:56 +0800 | Subject | Re: [PATCH 1/2] workqueue: pin the pool while it is managing |
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On Thu, May 28, 2020 at 4:08 PM Sebastian Andrzej Siewior <bigeasy@linutronix.de> wrote: > > On 2020-05-28 03:06:55 [+0000], Lai Jiangshan wrote: > > So that put_unbound_pool() can ensure all workers in idle, > > no unfinished manager. And it doens't need to wait any manager > > and can go to delete all the idle workers straight away. > > > > Also removes manager waitqueue, because it is unneeded and as > > Sebastian Andrzej Siewior said: > > > > The workqueue code has it's internal spinlock (pool::lock) and also > > implicit spinlock usage in the wq_manager waitqueue. These spinlocks > > are converted to 'sleeping' spinlocks on a RT-kernel. > > > > Workqueue functions can be invoked from contexts which are truly atomic > > even on a PREEMPT_RT enabled kernel. Taking sleeping locks from such > > contexts is forbidden. > > > > pool::lock can be converted to a raw spinlock as the lock held times > > are short. But the workqueue manager waitqueue is handled inside of > > pool::lock held regions which again violates the lock nesting rules > > of raw and regular spinlocks. > > This seems to work for my test case I had test my chance. And lockdep > didn't complain so… > > If you prefer this over my 1/2 what do we do about 2/2? Do you want me > to repost it?
I think we can just wait until Tejun reviews them.
If there is something wrong that I missed in my patch, your patches are the best choice.
If I need to update my patch, I will repost the 3 patches (2 of mine, the 2/2 of yours). At least I forgot to add "Reported-by Sebastian Andrzej Siewior <bigeasy@linutronix.de>" in the patch.
If Tejun queues my patches right away, you can rebase the 2/2 of yours and repost it.
Lai
> > Sebastian
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