Re: [PATCH -v2 1/5] sched: Fix ttwu() race
From: Paul E. McKenney
Date: Fri Jul 24 2020 - 13:55:44 EST
On Thu, Jul 23, 2020 at 10:11:28PM +0200, Peter Zijlstra wrote:
> On Thu, Jul 23, 2020 at 08:41:03PM +0100, Chris Wilson wrote:
> > I am very sorry for the wild goose chase.
> *phew*... all good then. I was starting to go a little ga-ga trying to
> make sense of things.
> Arguably we should probably do something like:
> @@ -4555,7 +4572,7 @@ asmlinkage __visible void __sched preempt_schedule_irq(void)
> int default_wake_function(wait_queue_entry_t *curr, unsigned mode, int wake_flags,
> void *key)
> - return try_to_wake_up(curr->private, mode, wake_flags);
> + return try_to_wake_up(curr->private, mode, wake_flags & WF_SYNC);
If you do:
Tested-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
This was about nine hours of each of the default rcutorture scenarios.
> Since I don't think anybody uses anything other than WF_SYNC, ever. And
> the rest of the WF_flags are used internally.
> Thanks Chris!