[PATCH 2 of 2] lock: include Linux pid namespace identifier in prefix

[Siddharth Agarwal]

On 2/13/17 13:03, Jun Wu wrote:
> I think it could be an extension outside core.


I'd say make it a clone-time option, turned off by default, with caveats 
documented. At FB we ban the situations where flock wouldn't work for 
scalability reasons anyway.

Note that flock requires the file be permanently on disk. We shouldn't 
use .hg/lock and .hg/wlock -- instead, we'll probably have to 
create/assume new files .hg/flock and .hg/fwlock.]