Re: [PATCH v2 09/17] debugobjects: Make object hash locks nestable terminal locks

From: Peter Zijlstra
Date: Fri Dec 07 2018 - 04:47:55 EST


On Mon, Nov 19, 2018 at 01:55:18PM -0500, Waiman Long wrote:
> By making the object hash locks nestable terminal locks, we can avoid
> a bunch of unnecessary lockdep validations as well as saving space
> in the lockdep tables.

So the 'problem'; which you've again not explained; is that debugobjects
has the following lock order:

&db->lock
&pool_lock

And you seem to want to tag '&db->lock' as terminal, which is obviuosly
a big fat lie.

You've also not explained why it is safe to do this (I think it actually
is, but you really should've spelled it out).

Furthermore; you've not justified any of this 'insanity' with numbers.
What do we gain with this nestable madness that justifies the crazy?