[RFC PATCH 02/21] Add a prelocked wake-up

[David Howells]

Linus Torvalds <torvalds at linux-foundation.org> wrote:

> > Add a wakeup call for a case whereby the caller already has the waitqueue
> > spinlock held.
> 
> That naming is crazy.

Sorry, yeah.  This is a bit hacked together at the moment and needs some more
tidying up.  I've had a lot of problems with performance regressions of up to
40% from seemingly simple changes involving moving locks around - it turns out
that the problem was that I was running with kasan enabled.

David