Re: [PATCH bpf-next v4 1/5] bpf: Add bitset map with bloom filter capabilities

[Alexei Starovoitov <ast@fb.com>]

On 10/12/21 5:11 PM, Martin KaFai Lau wrote:
> On Tue, Oct 12, 2021 at 03:46:47PM -0700, Joanne Koong wrote:
>> I'm also open to adding the bloom filter map and then in the
>> future, if/when there is a need for the bitset map, adding that as a
>> separate map. In that case, we could have the bitset map take in
>> both key and value where key = the bitset index and value = 0 or 1.
> v4 uses nr_hash_funcs is 0 (i.e. map_extra is 0) to mean bitset
> and non-zero to mean bloom filter.
> 
> Since the existing no-key API can be reused and work fine with bloom
> filter, my current thinking is it can start with bloom filter first
> and limit the nr_hash_funcs to be non-zero.
> 
> If in the future a bitset map is needed and the bloom filter API can
> be reused, the non-zero check can be relaxed.  If not, a separate
> API/map needs to be created for bitset anyway.
> 

sounds good to me.
let's drop bitset for now since there doesn't seem to be a consensus.