Re: [PATCH RFC bpf-next v2 00/18] bpf: Introduce resizable hash map

Mykyta Yatsenko
2026-04-20T11:46:02Z

On 4/18/26 1:43 AM, Herbert Xu wrote:
> On Fri, Apr 17, 2026 at 04:16:34PM +0100, Mykyta Yatsenko wrote:
>>
>> Changing interface is practically not possible - this comes from the bpf
>> syscall.
>> Linked list solution: we probably can't afford it performance-wise, it's not
>> worth it to pay for the linked list maintenance in insert/delete operations,
>> to make traversals work well.
>
> What performance penalty? The linked list is just a pair of pointers.
>
> Memory-wise it'll be two extra pointers per node.
>
> Cheers,

I'm concerned about pointer chasing, when we inserting a new element to
the list or removing existing, we'll need to update pointers of the
neighboring elements. It'll be nice to measure it, of course, let me try
to prototype it.