Hello,

On Tue, Nov 24, 2015 at 12:23:53PM -0800, Linus Torvalds wrote:

instead (possibly just "spin_unlock_wait()" - but the explicit loop

I see.  Wasn't thinking about cache traffic.  Yeah, spin_unlock_wait()
seems a lot better.

might be worth it if you then want to check the "canceling" flag
independently of the lock state too).

In general, it's very dangerous to try to cook up your own locking
rules. People *always* get it wrong.

It's either trylock on timer side or timer active spinning trick on
canceling side, so this seems the lesser of the two evils.

Thanks.

-- 
tejun