On Fri, 22 Oct 2021, Mel Gorman wrote: > On Fri, Oct 22, 2021 at 12:15:10PM +1100, NeilBrown wrote: > > > In general, I still don't like the use of wake_up_all(), though it won't > > cause incorrect behaviour. > > > > Removing wake_up_all would be tricky. I think there is a misunderstanding. Removing wake_up_all() is as simple as s/wake_up_all/wake_up/ If you used prepare_to_wait_exclusive(), then wake_up() would only wake one waiter, while wake_up_all() would wake all of them. As you use prepare_to_wait(), wake_up() will wake all waiters - as will wake_up_all(). When I see "wake_up_all()" I assume it is an exclusive wait, and that for some reason this particular wake_up needs to wake up all waiters. That is not the case here. I suspect it would be clearer if "wake_up" always woke everything, and "wake_up_one" was the special case - but unfortunately that isn't what we have. There are other non-exclusive waiters which use wake_up_all(), but the vast majority of wakeups use wake_up(), and most of those are for non-exclusive waiters. Thanks, NeilBrown
