Re: [PATCHv2] attr: convert to new threadsafe API

Johannes Sixt [off-list ref] writes:

Sigh. DCLP, the Double Checked Locking Pattern. ...
I suggest you go without it, then measure, and only *then* optimize if
it is a bottleneck. 

That comes from me in earlier discussion before the patch, namely in
[ref], where I wondered if
a cheap check outside the lock may be a possible optimization
opportunity, as this is a classic singleton that will not be
deinitialized, and once the codepath gets exercised, we would be
taking the "nothing to do" route 100% of the time.