Messages in this thread | | | From | Lai Jiangshan <> | Date | Wed, 3 Jun 2020 07:13:32 +0800 | Subject | Re: [PATCH] workqueue: ensure all flush_work() completed when being destoryed |
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On Wed, Jun 3, 2020 at 12:13 AM Tejun Heo <tj@kernel.org> wrote: > > Hello, Lai. > > On Tue, Jun 02, 2020 at 01:49:14PM +0000, Lai Jiangshan wrote: > > +static void dec_nr_in_flight_flush_work(struct workqueue_struct *wq) > > +{ > > + if (atomic_dec_and_test(&wq->nr_flush_work)) > > Do you think it'd make sense to put this in pwq so that it can be > synchronized with the pool lock instead of using a separate atomic counter? >
Hello, Tejun
When the counter is put in pwq, there will be a per-pwq counter, a per-pwq completion or pointer and a flush_workqueue_prep_pwqs()-like function (although simpler) to set up them before waiting for them.
It would sound like the V1 patch. per-pwq counter may have better performance over per-wq atomic, it seems too tiny to add code complicity. V1 has the simplest pwq_dec_nr_in_flight() except there is too much WARN_ON_ONCE() in flush_no_color().
Thanks Lai
> Makes sense to me otherwise. > > Thanks. > > -- > tejun
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