[lttng-dev] [URCU PATCH 1/3] wfcqueue: implement concurrency-efficient queue

[Paolo Bonzini]

Il 02/10/2012 16:14, Mathieu Desnoyers ha scritto:
> +/*
> + * Concurrent queue with wait-free enqueue/blocking dequeue.
> + *
> + * Inspired from half-wait-free/half-blocking queue implementation done by
> + * Paul E. McKenney.
> + *
> + * Mutual exclusion of __cds_wfcq_* API
> + *
> + * Unless otherwise stated, the caller must ensure mutual exclusion of
> + * queue update operations "dequeue" and "splice" (for source queue).
> + * Queue read operations "first" and "next" need to be protected against
> + * concurrent "dequeue" and "splice" (for source queue) by the caller.
> + * "enqueue", "splice" (for destination queue), and "empty" are the only
> + * operations that can be used without any mutual exclusion.
> + * Mutual exclusion can be ensured by holding cds_wfcq_dequeue_lock().
> + *
> + * For convenience, cds_wfcq_dequeue_blocking() and
> + * cds_wfcq_splice_blocking() hold the dequeue lock.
> + */

Hi,

can you add a for-like macro for iteration?  Iteration does not require
holding the lock and assumes that you are the sole user of the data
structure, which is useful together with splice.

Paolo