system wide mutex

[Asaf Las]

Hi 

Which one is most recommended to use for mutex alike locking to 
achieve atomic access to single resource:

- fcntl.lockf
- os.open() with O_SHLOCK and O_EXLOCK 
- https://pypi.python.org/pypi/lockfile/0.9.1
- https://pypi.python.org/pypi/zc.lockfile/1.1.0
- any other ?

Thanks 

/Asaf