Re: INFO: rcu detected stall in xfrm_hash_rebuild

From: Florian Westphal
Date: Fri Dec 14 2018 - 11:23:44 EST

Christophe Gouault <christophe.gouault@xxxxxxxxx> wrote:
> The main use cases I have encountered and tried to address with the
> hash-based lookup were network operator use cases:
> - a lot of dynamic /32 <=> /32 policies (protecting GTP tunnels)
> - or a lot of dynamic policies with the same prefix lengths (e.g. /16 <=> /24)
> and a few non-hashed policies stored in the linked list.

Thanks for the detailed information.


> Could you verify how the configuration time would behave in such use
> cases if the hash-based lookup was replaced by a tree-based lookup?

I won't send a patch to remove your work, at least not at this time.

In case I'd do this removal (thresholds, hash table, or both)
i will make these tests to see how large the impact is.