On 09/19/16 at 07:00pm, Herbert Xu wrote: > The insecure_elasticity setting is an ugly wart brought out by > users who need to insert duplicate objects (that is, distinct > objects with identical keys) into the same table. > > In fact, those users have a much bigger problem. Once those > duplicate objects are inserted, they don't have an interface to > find them (unless you count the walker interface which walks > over the entire table). > > Some users have resorted to doing a manual walk over the hash > table which is of course broken because they don't handle the > potential existence of multiple hash tables. The result is that > they will break sporadically when they encounter a hash table > resize/rehash. > > This patch provides a way out for those users, at the expense > of an extra pointer per object. Essentially each object is now > a list of objects carrying the same key. The hash table will > only see the lists so nothing changes as far as rhashtable is > concerned. > > To use this new interface, you need to insert a struct rhlist_head > into your objects instead of struct rhash_head. While the hash > table is unchanged, for type-safety you'll need to use struct > rhltable instead of struct rhashtable. All the existing interfaces > have been duplicated for rhlist, including the hash table walker. > > One missing feature is nulls marking because AFAIK the only potential > user of it does not need duplicate objects. Should anyone need > this it shouldn't be too hard to add. > > Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> Nice, I like how this simplifies users! Is this suitable for ILA as well? Acked-by: Thomas Graf <tgraf@xxxxxxx>
