Messages in this thread | | | Date | Tue, 18 Dec 2018 14:14:19 +0100 | From | Peter Zijlstra <> | Subject | Re: [RFC] locking/rwsem: Avoid issuing wakeup before setting the reader waiter to nil |
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On Tue, Dec 18, 2018 at 02:10:31PM +0100, Peter Zijlstra wrote: > On Mon, Dec 17, 2018 at 12:53:10PM -0800, Davidlohr Bueso wrote:
> > So how about the following to reduce some of the performance penalty (at > > the cost of more complexity)? > > I'd rather do it like so, except I'm still conflicted on the naming.
> +void wake_q_add(struct wake_q_head *head, struct task_struct *task) > +{ > + if (__wake_q_add(head, task)) > + get_task_struct(task); > +} > + > +void wake_q_add_safe(struct wake_q_head *head, struct task_struct *task) > +{ > + if (!__wake_a_add(head, task)) > + put_task_struct(task); > }
That is, in the one case it has internal reference counting, in the other case it consumes the reference counting.
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