Re: [PATCH v2 08/17] locking/lockdep: Add support for nestable terminal locks

From: Peter Zijlstra
Date: Fri Dec 07 2018 - 04:52:26 EST


On Fri, Dec 07, 2018 at 10:22:52AM +0100, Peter Zijlstra wrote:
> On Mon, Nov 19, 2018 at 01:55:17PM -0500, Waiman Long wrote:
> > There are use cases where we want to allow nesting of one terminal lock
> > underneath another terminal-like lock. That new lock type is called
> > nestable terminal lock which can optionally allow the acquisition of
> > no more than one regular (non-nestable) terminal lock underneath it.
>
> I think I asked for a more coherent changelog on this. The above is
> still self contradictory and doesn't explain why you'd ever want such a
> 'misfeature' :-)

So maybe call the thing penterminal (contraction of penultimate and
terminal) locks and explain why this annotation is safe -- in great
detail.