Re: [RFC] locking/rwsem: Avoid issuing wakeup before setting the reader waiter to nil

From: Davidlohr Bueso
Date: Thu Nov 29 2018 - 13:17:28 EST


On Thu, 29 Nov 2018, Peter Zijlstra wrote:

On Thu, Nov 29, 2018 at 12:58:26PM -0500, Waiman Long wrote:
OK, you convinced me. However, that can still lead to anonymous wakeups
that can be problematic if it happens in certain places. Should we try
to reduce anonymous wakeup as much as possible?

No, we should at all times accept and expect spurious wakeups.

Right, when this was merged, spurious wakeups were acknowledged as quite
possible.