/*
* pool_cache_invalidate:
*
* Invalidate a pool cache (destruct and release all of the
* cached objects). Does not reclaim objects from the pool.
*
* Note: For pool caches that provide constructed objects, there
* is an assumption that another level of synchronization is occurring
* between the input to the constructor and the cache invalidation.
*
* Invalidation is a costly process and should not be called from
* interrupt context.
*/