Hi, Currently, we have BPF kfuncs which allow BPF programs to add and remove elements from a BPF linked list. However, we're currently missing other simple capabilities, like being able to iterate over the elements within the BPF linked lists. What is our current appetite with regards to adding new BPF kfuncs that support this kind of capability to BPF linked lists? I know that we're now somewhat advocating for using BPF arenas whenever and wherever possible, especially when it comes to building out and supporting more complicated data structures in BPF. However, IMO BPF linked lists still have their place. Specifically, and as of now, I'd argue that the BPF linked list implementation could be considered more memory efficient when compared to a BPF arena backed linked list implementation. This is purely due to the fact that the BPF linked list implementation can perform more constrained memory allocations for elements via bpf_obj_new_impl() based on the demand, whereas for a BPF arena based implementation a BPF program needs to allocate memory upfront in terms of the number of pages (modulo the fact that not all pages for the BPF arena will necessarily be reserved upfront). The fact that allocations are performed in terms of multiples of PAGE_SIZE can lead to unnecessary memory wastage.
