On Mon, 8 Jul 2024 13:58:31 +0200 Florian Westphal <fw@xxxxxxxxx> > Hillf Danton <hdanton@xxxxxxxx> wrote: > > On Sun, 7 Jul 2024 10:08:24 +0200 Florian Westphal <fw@xxxxxxxxx> > > > Hillf Danton <hdanton@xxxxxxxx> wrote: > > > > > I think this change might be useful as it also documents > > > > > this requirement. > > > > > > > > Yes it is boy and the current reproducer triggered another warning [1,2]. > > > > > > > > [1] https://lore.kernel.org/lkml/20240706231332.3261-1-hdanton@xxxxxxxx/ > > > > > > The WARN is incorrect. The destroy list can be non-empty; i already > > > tried to explain why. > > > > > That warning as-is could be false positive but it could be triggered with a > > single netns. > > How? > You saw the below cpu diagram, no? > > cpu1 cpu2 cpu3 > > --- --- --- > > nf_tables_trans_destroy_work() > > spin_lock(&nf_tables_destroy_list_lock); > > > > // 1) clear the destroy list > > list_splice_init(&nf_tables_destroy_list, &head); > > spin_unlock(&nf_tables_destroy_list_lock); > > > > nf_tables_commit_release() > > spin_lock(&nf_tables_destroy_list_lock); > > > > // 2) refill the destroy list > > list_splice_tail_init(&nft_net->commit_list, &nf_tables_destroy_list); > > spin_unlock(&nf_tables_destroy_list_lock); > > schedule_work(&trans_destroy_work); > > mutex_unlock(&nft_net->commit_mutex); > > So you're saying work can be IDLE after schedule_work()? > I got your point but difficult to explain you. In simple words, like runqueue, workqueue has latency. > I'm not following at all. This does not matter but is why I added tj to the cc list.
