[lustre-devel] [PATCH 27/37] lustre: discard lu_ref

[Andreas Dilger]

> On Feb 26, 2019, at 18:17, NeilBrown <neilb at suse.com> wrote:
> 
> On Sun, Feb 24 2019, James Simmons wrote:
> 
>>> struct lu_ref is always an empty structure, and the functions
>>> which manipulate it do nothing.
>>> So this is not being tested and so cannot be trusted.
>>> So remove all these calls and field declarations.
>> 
>> Or we can make lu_ref really work and always test with it :-)
> 
> We could ... though a lot of the code has been removed already, I was
> just finishing the job.
> 
> How useful is this stuff?
> Has it actually helped to find any bugs?
> Does it do any run-time checks, or it is just
> there to help you pull apart a crash-dump?
> 
> I think there is a real cost in having these extra linkages.  I'd like
> to be clear what the benefit is.

I've never used it myself, though I know a few developers that did in the
past.  That said, most of the time they needed to use it to debug some
issue they had to push a patch to fix it first...

Mike, Alex, you are most likely to use this code - do you think it is
still useful?

Cheers, Andreas
---
Andreas Dilger
Principal Lustre Architect
Whamcloud