[senderista]

Pretty much, given that any decent pthreads implementation will offer an adaptive mutex. Unless you really need a mutex the size of a single bit or byte (which likely implies false sharing), there's little reason to ever use a pure spinlock, since a mutex with adaptive spinning (up to context switch latency) gives you the same performance for short critical sections without the disastrous worst-case behavior.

[nly]

Some people don't want to block for a microsecond when their lock goes 1ns over your adaptive mutexes spin deadline. That kind of jitter is unacceptable.

[senderista]

I assume those people are already running 1 pinned thread/core and have no issues with unbounded spinning in the first place. In which case, go nuts.