On Wed, Aug 5, 2020 at 4:14 PM David Howells <dhowells@xxxxxxxxxx> wrote: > However, looking up that identifier requires some sort of structure for doing > this and it's kind of worst case for the IDR tree as the keys are gradually > going to spread out, causing it to eat more memory. It may be a tradeoff > worth making, and the memory consumption might not be that bad - or we could > use some other data structure such as an rbtree. idr_alloc_cyclic() seems to be a good template for doing the lower 32bit allocation, and we can add code to increment the high 32bit on wraparound. Lots of code uses idr_alloc_cyclic() so I guess it shouldn't be too bad in terms of memory use or performance. Thanks, Miklos
