Re: [nf-next 0/2] netfilter: nf_tables: make set flush more resistant to memory pressure

[Pablo Neira Ayuso <pablo@netfilter.org>]

Hi Florian,

On Fri, Jul 04, 2025 at 02:30:16PM +0200, Florian Westphal wrote:
> Removal of many set elements, e.g. during set flush or ruleset
> deletion, can sometimes fail due to memory pressure.
> Reduce likelyhood of this happening and enable sleeping allocations
> for this.

I am exploring to skip the allocation of the transaction objects for
this case. This needs a closer look to deal with batches like:

 delelem + flush set + abort
 flush set + del set + abort

Special care need to be taken to avoid restoring the state of the
element twice on abort.

This would allow to save the memory allocation entirely, as well as
speeding up the transaction handling.

From userspace, the idea would be to print this event:

        flush set inet x y

to skip a large burst of events when a set is flushed.

Is this worth to be pursued?