On 08/24/2012 10:33 PM, Tejun Heo wrote: > Hello, Sasha. > > On Fri, Aug 24, 2012 at 10:11:55PM +0200, Sasha Levin wrote: >>> If this implementation is about the common trivial case, why not just >>> have the usual DECLARE/DEFINE_HASHTABLE() combination? >> >> When we add the dynamic non-resizable support, how would DEFINE_HASHTABLE() look? > > Hmmm? DECLARE/DEFINE are usually for static ones. Yup, but we could be using the same API for dynamic non-resizable and static if we go with the DECLARE/hash_init. We could switch between them (and other implementations) without having to change the code. >>> I don't know. If we stick to the static (or even !resize dymaic) >>> straight-forward hash - and we need something like that - I don't see >>> what the full encapsulation buys us other than a lot of trivial >>> wrappers. >> >> Which macros do you consider as trivial within the current API? >> >> Basically this entire thing could be reduced to DEFINE/DECLARE_HASHTABLE and >> get_bucket(), but it would make the life of anyone who wants a slightly >> different hashtable a hell. > > Wouldn't the following be enough to get most of the benefits? > > * DECLARE/DEFINE > * hash_head() > * hash_for_each_head() > * hash_add*() > * hash_for_each_possible*() * hash_for_each*() ? Why do we need hash_head/hash_for_each_head()? I haven't stumbled on a place yet that needed direct access to the bucket itself. Consider the following list: - DECLARE - hash_init - hash_add - hash_del - hash_hashed - hash_for_each_[rcu, safe] - hash_for_each_possible[rcu, safe] This basically means 11 macros/functions that would let us have full encapsulation and will make it very easy for future implementations to work with this API instead of making up a new one. It's also not significantly (+~2-3) more than the ones you listed. >> I think that right now the only real trivial wrapper is hash_hashed(), and I >> think it's a price worth paying to have a single hashtable API instead of >> fragmenting it when more implementations come along. > > I'm not objecting strongly against full encapsulation but having this > many thin wrappers makes me scratch my head. > > Thanks. > -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
