Messages in this thread | | | Date | Wed, 01 Aug 2012 21:06:50 +0200 | From | Sasha Levin <> | Subject | Re: [RFC 1/4] hashtable: introduce a small and naive hashtable |
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On 08/01/2012 08:27 PM, Tejun Heo wrote: > On Wed, Aug 01, 2012 at 08:24:32PM +0200, Sasha Levin wrote: >> On 08/01/2012 08:21 PM, Tejun Heo wrote: >>> On Wed, Aug 01, 2012 at 08:19:52PM +0200, Sasha Levin wrote: >>>> If we switch to using functions, we could no longer hide it anywhere >>>> (we'd need to either turn the buckets into a struct, or have the >>>> user pass it around to all functions). >>> >>> Create an outer struct hash_table which remembers the size? >> >> Possible. I just wanted to avoid creating new structs where they're not really required. >> >> Do you think it's worth it for eliminating those two macros? > > What if someone wants to allocate hashtable dynamically which isn't > too unlikely? I think it's best to stay away from macro tricks as > much as possible although I gotta admit I fall into the macro trap > more often than I would like.
Using a struct makes the dynamic case much easier, but it complicates the static case.
Previously we could create the buckets statically.
Consider this struct:
struct hash_table { u32 bits; struct hlist_head buckets[]; };
We can't make any code that wraps this to make it work properly statically allocated nice enough to be acceptable.
What if when creating the buckets, we actually allocate bits+1 buckets, and use the last bucket not as a bucket but as the bitcount? It looks like a hack but I think it's much nicer than the previous.
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