[bind10-dev] Resolver - address database requirements

[Stephen Morris]

On 4 Oct 2010, at 10:48, Robert Edmonds wrote:
> 
> i think i may not have been clear on the lock-less LRU variant.  the
> entries in the per-thread expiration lists (at least in my
> implementation) form completely disjoint sets -- i.e., the thread that
> allocates the entry and appends it to the expiration list must be the
> same thread that expires it.  the same entry is never present in more
> than one of the expiration queues at the same time.

OK, I understand.  That's quite neat.

This relies on a frequently-accessed entry being periodically accessed by the creating thread to prevent it from expiring.  I guess that it will be fairly unlikely for a frequently accessed name not to be accessed more or less evenly by all the threads, so that approach does avoid an additional mutex (and associated contention), albeit at the expense of having thread-specific storage.

Stephen