[openib-general] uverbs: pthread_mutex -> pthread_spinlock ?

[Michael S. Tsirkin]

I am able to shave about 200ns off the rdma post latency,
by using pthread_spinlock instead of pthread_mutex for protecting
the qp post op in libmthca.

I'm aware of course that a context switch when spinlock is held may
waste a whole timeslice , but maybe for short operations such as this
it's reasonable to use spinlocks?

-- 
MST - Michael S. Tsirkin