I dunno, it seems to me that the standard mutex performs very well on all scenarios, and doesn't have any significant downsides, except for the hogging case, which could be fixed by assigning the non-hogging threads a higher priority.
Whereas parking_lot has a ton of problematic scenarios, where after the spinlock times out, and it yields the thread to the OS, which has no idea to wake up the thread after the resource is unblocked.
It could be even argued that preventing starvation is outside the design scope of the Mutex as a construct, as it only guarantees mutual exclusion and that the highest priority waiting thread should get access to it.
Whereas parking_lot has a ton of problematic scenarios, where after the spinlock times out, and it yields the thread to the OS, which has no idea to wake up the thread after the resource is unblocked.
It could be even argued that preventing starvation is outside the design scope of the Mutex as a construct, as it only guarantees mutual exclusion and that the highest priority waiting thread should get access to it.