Re: [RFC PATCH 07/12] locking/lockdep: Add support for nested terminal locks

Waiman Long
2018-11-11T00:30:59Z

On 11/10/2018 09:20 AM, Peter Zijlstra wrote:
> On Thu, Nov 08, 2018 at 03:34:23PM -0500, Waiman Long wrote:
>> There are use cases where we want to allow 2-level nesting of one
>> terminal lock underneath another one. So the terminal lock type is now
>> extended to support a new nested terminal lock where it can allow the
>> acquisition of another regular terminal lock underneath it.
> You're stretching things here... If you're allowing things under it, it
> is no longer a terminal lock.
>
> Why would you want to do such a thing?

A majority of the gain in debugobjects is to make the hash lock a kind
of terminal lock. Yes, I may be stretching it a bit here. I will take
back the nesting patch and consider doing that in a future patch.

Cheers,
Longman