Re: [PATCH v2] tools/memory-model: Add extra ordering for locks and remove it for ordinary release/acquire

Linus Torvalds
2018-07-14T02:58:54Z

On Fri, Jul 13, 2018 at 6:51 PM Alan Stern <stern@rowland.harvard.edu> wrote:
>
> The point being that the scenarios under discussion in this thread all
> fall most definitely into the "Non-standard usage; you'd better know
> exactly what you're doing" category.

Well, yes and no.

The thing is, people expected unlock+lock to give a memory ordering.
It happened in RCU, and it's happened before elsewhere.

So it *is* the "pure locking" thing that ends up confusing people.
Yes, you have some other access that then cares about the memory
ordering, but this is a fairly natural expectation to have
(considering that we've had the same issue before).

Linus